diff --git a/src/applications/audit/editor/PhabricatorAuditEditor.php b/src/applications/audit/editor/PhabricatorAuditEditor.php
index c39be75366..d142bd60cd 100644
--- a/src/applications/audit/editor/PhabricatorAuditEditor.php
+++ b/src/applications/audit/editor/PhabricatorAuditEditor.php
@@ -1,848 +1,859 @@
 <?php
 
 final class PhabricatorAuditEditor
   extends PhabricatorApplicationTransactionEditor {
 
   const MAX_FILES_SHOWN_IN_EMAIL = 1000;
 
   private $affectedFiles;
   private $rawPatch;
   private $auditorPHIDs = array();
 
   private $didExpandInlineState = false;
   private $oldAuditStatus = null;
 
   public function setRawPatch($patch) {
     $this->rawPatch = $patch;
     return $this;
   }
 
   public function getRawPatch() {
     return $this->rawPatch;
   }
 
   public function getEditorApplicationClass() {
     return 'PhabricatorDiffusionApplication';
   }
 
   public function getEditorObjectsDescription() {
     return pht('Audits');
   }
 
   public function getTransactionTypes() {
     $types = parent::getTransactionTypes();
 
     $types[] = PhabricatorTransactions::TYPE_COMMENT;
     $types[] = PhabricatorTransactions::TYPE_EDGE;
     $types[] = PhabricatorTransactions::TYPE_INLINESTATE;
 
     $types[] = PhabricatorAuditTransaction::TYPE_COMMIT;
 
     // TODO: These will get modernized eventually, but that can happen one
     // at a time later on.
     $types[] = PhabricatorAuditActionConstants::INLINE;
 
     return $types;
   }
 
   protected function expandTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_INLINESTATE:
           $this->didExpandInlineState = true;
           break;
       }
     }
 
     $this->oldAuditStatus = $object->getAuditStatus();
 
     $object->loadAndAttachAuditAuthority(
       $this->getActor(),
       $this->getActingAsPHID());
 
     return parent::expandTransactions($object, $xactions);
   }
 
   protected function transactionHasEffect(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditActionConstants::INLINE:
         return $xaction->hasComment();
     }
 
     return parent::transactionHasEffect($object, $xaction);
   }
 
   protected function getCustomTransactionOldValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditActionConstants::INLINE:
       case PhabricatorAuditTransaction::TYPE_COMMIT:
         return null;
     }
 
     return parent::getCustomTransactionOldValue($object, $xaction);
   }
 
   protected function getCustomTransactionNewValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditActionConstants::INLINE:
       case PhabricatorAuditTransaction::TYPE_COMMIT:
         return $xaction->getNewValue();
     }
 
     return parent::getCustomTransactionNewValue($object, $xaction);
   }
 
   protected function applyCustomInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditActionConstants::INLINE:
       case PhabricatorAuditTransaction::TYPE_COMMIT:
         return;
     }
 
     return parent::applyCustomInternalTransaction($object, $xaction);
   }
 
   protected function applyCustomExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditTransaction::TYPE_COMMIT:
         return;
       case PhabricatorAuditActionConstants::INLINE:
         $reply = $xaction->getComment()->getReplyToComment();
         if ($reply && !$reply->getHasReplies()) {
           $reply->setHasReplies(1)->save();
         }
         return;
     }
 
     return parent::applyCustomExternalTransaction($object, $xaction);
   }
 
   protected function applyBuiltinExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_INLINESTATE:
         $table = new PhabricatorAuditTransactionComment();
         $conn_w = $table->establishConnection('w');
         foreach ($xaction->getNewValue() as $phid => $state) {
           queryfx(
             $conn_w,
             'UPDATE %T SET fixedState = %s WHERE phid = %s',
             $table->getTableName(),
             $state,
             $phid);
         }
         break;
     }
 
     return parent::applyBuiltinExternalTransaction($object, $xaction);
   }
 
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     // Load auditors explicitly; we may not have them if the caller was a
     // generic piece of infrastructure.
 
     $commit = id(new DiffusionCommitQuery())
       ->setViewer($this->requireActor())
       ->withIDs(array($object->getID()))
       ->needAuditRequests(true)
       ->executeOne();
     if (!$commit) {
       throw new Exception(
         pht('Failed to load commit during transaction finalization!'));
     }
     $object->attachAudits($commit->getAudits());
 
     $status_concerned = PhabricatorAuditStatusConstants::CONCERNED;
     $status_closed = PhabricatorAuditStatusConstants::CLOSED;
     $status_resigned = PhabricatorAuditStatusConstants::RESIGNED;
     $status_accepted = PhabricatorAuditStatusConstants::ACCEPTED;
     $status_concerned = PhabricatorAuditStatusConstants::CONCERNED;
 
     $actor_phid = $this->getActingAsPHID();
     $actor_is_author = ($object->getAuthorPHID()) &&
       ($actor_phid == $object->getAuthorPHID());
 
     $import_status_flag = null;
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorAuditTransaction::TYPE_COMMIT:
           $import_status_flag = PhabricatorRepositoryCommit::IMPORTED_HERALD;
           break;
       }
     }
 
     $old_status = $this->oldAuditStatus;
 
     $requests = $object->getAudits();
     $object->updateAuditStatus($requests);
 
     $new_status = $object->getAuditStatus();
 
     $object->save();
 
     if ($import_status_flag) {
       $object->writeImportStatusFlag($import_status_flag);
     }
 
     $partial_status = PhabricatorAuditCommitStatusConstants::PARTIALLY_AUDITED;
 
     // If the commit has changed state after this edit, add an informational
     // transaction about the state change.
     if ($old_status != $new_status) {
       if ($new_status == $partial_status) {
         // This state isn't interesting enough to get a transaction. The
         // best way we could lead the user forward is something like "This
         // commit still requires additional audits." but that's redundant and
         // probably not very useful.
       } else {
         $xaction = $object->getApplicationTransactionTemplate()
           ->setTransactionType(DiffusionCommitStateTransaction::TRANSACTIONTYPE)
           ->setOldValue($old_status)
           ->setNewValue($new_status);
 
         $xaction = $this->populateTransaction($object, $xaction);
 
         $xaction->save();
       }
     }
 
     // Collect auditor PHIDs for building mail.
     $this->auditorPHIDs = mpull($object->getAudits(), 'getAuditorPHID');
 
     return $xactions;
   }
 
   protected function expandTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $xactions = parent::expandTransaction($object, $xaction);
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditTransaction::TYPE_COMMIT:
         $request = $this->createAuditRequestTransactionFromCommitMessage(
           $object);
         if ($request) {
           $xactions[] = $request;
           $this->setUnmentionablePHIDMap($request->getNewValue());
         }
         break;
       default:
         break;
     }
 
     if (!$this->didExpandInlineState) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_COMMENT:
           $this->didExpandInlineState = true;
 
           $actor_phid = $this->getActingAsPHID();
           $actor_is_author = ($object->getAuthorPHID() == $actor_phid);
           if (!$actor_is_author) {
             break;
           }
 
           $state_map = PhabricatorTransactions::getInlineStateMap();
 
           $inlines = id(new DiffusionDiffInlineCommentQuery())
             ->setViewer($this->getActor())
             ->withCommitPHIDs(array($object->getPHID()))
             ->withFixedStates(array_keys($state_map))
             ->execute();
 
           if (!$inlines) {
             break;
           }
 
           $old_value = mpull($inlines, 'getFixedState', 'getPHID');
           $new_value = array();
           foreach ($old_value as $key => $state) {
             $new_value[$key] = $state_map[$state];
           }
 
           $xactions[] = id(new PhabricatorAuditTransaction())
             ->setTransactionType(PhabricatorTransactions::TYPE_INLINESTATE)
             ->setIgnoreOnNoEffect(true)
             ->setOldValue($old_value)
             ->setNewValue($new_value);
           break;
       }
     }
 
     return $xactions;
   }
 
   private function createAuditRequestTransactionFromCommitMessage(
     PhabricatorRepositoryCommit $commit) {
 
     $actor = $this->getActor();
     $data = $commit->getCommitData();
     $message = $data->getCommitMessage();
 
     $result = DifferentialCommitMessageParser::newStandardParser($actor)
       ->setRaiseMissingFieldErrors(false)
       ->parseFields($message);
 
     $field_key = DifferentialAuditorsCommitMessageField::FIELDKEY;
     $phids = idx($result, $field_key, null);
 
     if (!$phids) {
       return array();
     }
 
     // If a commit lists its author as an auditor, just pretend it does not.
     foreach ($phids as $key => $phid) {
       if ($phid == $commit->getAuthorPHID()) {
         unset($phids[$key]);
       }
     }
 
     if (!$phids) {
       return array();
     }
 
     return $commit->getApplicationTransactionTemplate()
       ->setTransactionType(DiffusionCommitAuditorsTransaction::TRANSACTIONTYPE)
       ->setNewValue(
         array(
           '+' => array_fuse($phids),
         ));
   }
 
   protected function sortTransactions(array $xactions) {
     $xactions = parent::sortTransactions($xactions);
 
     $head = array();
     $tail = array();
 
     foreach ($xactions as $xaction) {
       $type = $xaction->getTransactionType();
       if ($type == PhabricatorAuditActionConstants::INLINE) {
         $tail[] = $xaction;
       } else {
         $head[] = $xaction;
       }
     }
 
     return array_values(array_merge($head, $tail));
   }
 
   protected function supportsSearch() {
     return true;
   }
 
   protected function expandCustomRemarkupBlockTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $changes,
     PhutilMarkupEngine $engine) {
 
     $actor = $this->getActor();
     $result = array();
 
     // Some interactions (like "Fixes Txxx" interacting with Maniphest) have
     // already been processed, so we're only re-parsing them here to avoid
     // generating an extra redundant mention. Other interactions are being
     // processed for the first time.
 
     // We're only recognizing magic in the commit message itself, not in
     // audit comments.
 
     $is_commit = false;
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorAuditTransaction::TYPE_COMMIT:
           $is_commit = true;
           break;
       }
     }
 
     if (!$is_commit) {
       return $result;
     }
 
     $flat_blocks = mpull($changes, 'getNewValue');
     $huge_block = implode("\n\n", $flat_blocks);
     $phid_map = array();
     $phid_map[] = $this->getUnmentionablePHIDMap();
     $monograms = array();
 
     $task_refs = id(new ManiphestCustomFieldStatusParser())
       ->parseCorpus($huge_block);
     foreach ($task_refs as $match) {
       foreach ($match['monograms'] as $monogram) {
         $monograms[] = $monogram;
       }
     }
 
     $rev_refs = id(new DifferentialCustomFieldDependsOnParser())
       ->parseCorpus($huge_block);
     foreach ($rev_refs as $match) {
       foreach ($match['monograms'] as $monogram) {
         $monograms[] = $monogram;
       }
     }
 
     $objects = id(new PhabricatorObjectQuery())
       ->setViewer($this->getActor())
       ->withNames($monograms)
       ->execute();
     $phid_map[] = mpull($objects, 'getPHID', 'getPHID');
 
 
     $reverts_refs = id(new DifferentialCustomFieldRevertsParser())
       ->parseCorpus($huge_block);
     $reverts = array_mergev(ipull($reverts_refs, 'monograms'));
     if ($reverts) {
       // Only allow commits to revert other commits in the same repository.
       $reverted_commits = id(new DiffusionCommitQuery())
         ->setViewer($actor)
         ->withRepository($object->getRepository())
         ->withIdentifiers($reverts)
         ->execute();
 
       $reverted_revisions = id(new PhabricatorObjectQuery())
         ->setViewer($actor)
         ->withNames($reverts)
         ->withTypes(
           array(
             DifferentialRevisionPHIDType::TYPECONST,
           ))
         ->execute();
 
       $reverted_phids =
         mpull($reverted_commits, 'getPHID', 'getPHID') +
         mpull($reverted_revisions, 'getPHID', 'getPHID');
 
       // NOTE: Skip any write attempts if a user cleverly implies a commit
       // reverts itself, although this would be exceptionally clever in Git
       // or Mercurial.
       unset($reverted_phids[$object->getPHID()]);
 
       $reverts_edge = DiffusionCommitRevertsCommitEdgeType::EDGECONST;
       $result[] = id(new PhabricatorAuditTransaction())
         ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
         ->setMetadataValue('edge:type', $reverts_edge)
         ->setNewValue(array('+' => $reverted_phids));
 
       $phid_map[] = $reverted_phids;
     }
 
     $phid_map = array_mergev($phid_map);
     $this->setUnmentionablePHIDMap($phid_map);
 
     return $result;
   }
 
   protected function buildReplyHandler(PhabricatorLiskDAO $object) {
     $reply_handler = new PhabricatorAuditReplyHandler();
     $reply_handler->setMailReceiver($object);
     return $reply_handler;
   }
 
   protected function getMailSubjectPrefix() {
     return PhabricatorEnv::getEnvConfig('metamta.diffusion.subject-prefix');
   }
 
   protected function getMailThreadID(PhabricatorLiskDAO $object) {
     // For backward compatibility, use this legacy thread ID.
     return 'diffusion-audit-'.$object->getPHID();
   }
 
   protected function buildMailTemplate(PhabricatorLiskDAO $object) {
     $identifier = $object->getCommitIdentifier();
     $repository = $object->getRepository();
 
     $summary = $object->getSummary();
     $name = $repository->formatCommitName($identifier);
 
     $subject = "{$name}: {$summary}";
 
     $template = id(new PhabricatorMetaMTAMail())
       ->setSubject($subject);
 
     $this->attachPatch(
       $template,
       $object);
 
     return $template;
   }
 
   protected function getMailTo(PhabricatorLiskDAO $object) {
     $phids = array();
 
     if ($object->getAuthorPHID()) {
       $phids[] = $object->getAuthorPHID();
     }
 
-    $status_resigned = PhabricatorAuditStatusConstants::RESIGNED;
     foreach ($object->getAudits() as $audit) {
       if (!$audit->isInteresting()) {
         // Don't send mail to uninteresting auditors, like packages which
         // own this code but which audits have not triggered for.
         continue;
       }
 
-      if ($audit->getAuditStatus() != $status_resigned) {
+      if (!$audit->isResigned()) {
         $phids[] = $audit->getAuditorPHID();
       }
     }
 
     $phids[] = $this->getActingAsPHID();
 
     return $phids;
   }
 
+  protected function newMailUnexpandablePHIDs(PhabricatorLiskDAO $object) {
+    $phids = array();
+
+    foreach ($object->getAudits() as $auditor) {
+      if ($auditor->isResigned()) {
+        $phids[] = $auditor->getAuditorPHID();
+      }
+    }
+
+    return $phids;
+  }
+
   protected function buildMailBody(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $body = parent::buildMailBody($object, $xactions);
 
     $type_inline = PhabricatorAuditActionConstants::INLINE;
     $type_push = PhabricatorAuditTransaction::TYPE_COMMIT;
 
     $is_commit = false;
     $inlines = array();
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() == $type_inline) {
         $inlines[] = $xaction;
       }
       if ($xaction->getTransactionType() == $type_push) {
         $is_commit = true;
       }
     }
 
     if ($inlines) {
       $body->addTextSection(
         pht('INLINE COMMENTS'),
         $this->renderInlineCommentsForMail($object, $inlines));
     }
 
     if ($is_commit) {
       $data = $object->getCommitData();
       $body->addTextSection(pht('AFFECTED FILES'), $this->affectedFiles);
       $this->inlinePatch(
         $body,
         $object);
     }
 
     $data = $object->getCommitData();
 
     $user_phids = array();
 
     $author_phid = $object->getAuthorPHID();
     if ($author_phid) {
       $user_phids[$author_phid][] = pht('Author');
     }
 
     $committer_phid = $data->getCommitDetail('committerPHID');
     if ($committer_phid && ($committer_phid != $author_phid)) {
       $user_phids[$committer_phid][] = pht('Committer');
     }
 
     foreach ($this->auditorPHIDs as $auditor_phid) {
       $user_phids[$auditor_phid][] = pht('Auditor');
     }
 
     // TODO: It would be nice to show pusher here too, but that information
     // is a little tricky to get at right now.
 
     if ($user_phids) {
       $handle_phids = array_keys($user_phids);
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($this->requireActor())
         ->withPHIDs($handle_phids)
         ->execute();
 
       $user_info = array();
       foreach ($user_phids as $phid => $roles) {
         $user_info[] = pht(
           '%s (%s)',
           $handles[$phid]->getName(),
           implode(', ', $roles));
       }
 
       $body->addTextSection(
         pht('USERS'),
         implode("\n", $user_info));
     }
 
     $monogram = $object->getRepository()->formatCommitName(
       $object->getCommitIdentifier());
 
     $body->addLinkSection(
       pht('COMMIT'),
       PhabricatorEnv::getProductionURI('/'.$monogram));
 
     return $body;
   }
 
   private function attachPatch(
     PhabricatorMetaMTAMail $template,
     PhabricatorRepositoryCommit $commit) {
 
     if (!$this->getRawPatch()) {
       return;
     }
 
     $attach_key = 'metamta.diffusion.attach-patches';
     $attach_patches = PhabricatorEnv::getEnvConfig($attach_key);
     if (!$attach_patches) {
       return;
     }
 
     $repository = $commit->getRepository();
     $encoding = $repository->getDetail('encoding', 'UTF-8');
 
     $raw_patch = $this->getRawPatch();
     $commit_name = $repository->formatCommitName(
       $commit->getCommitIdentifier());
 
     $template->addAttachment(
       new PhabricatorMetaMTAAttachment(
         $raw_patch,
         $commit_name.'.patch',
         'text/x-patch; charset='.$encoding));
   }
 
   private function inlinePatch(
     PhabricatorMetaMTAMailBody $body,
     PhabricatorRepositoryCommit $commit) {
 
     if (!$this->getRawPatch()) {
         return;
     }
 
     $inline_key = 'metamta.diffusion.inline-patches';
     $inline_patches = PhabricatorEnv::getEnvConfig($inline_key);
     if (!$inline_patches) {
       return;
     }
 
     $repository = $commit->getRepository();
     $raw_patch = $this->getRawPatch();
     $result = null;
     $len = substr_count($raw_patch, "\n");
     if ($len <= $inline_patches) {
       // We send email as utf8, so we need to convert the text to utf8 if
       // we can.
       $encoding = $repository->getDetail('encoding', 'UTF-8');
       if ($encoding) {
         $raw_patch = phutil_utf8_convert($raw_patch, 'UTF-8', $encoding);
       }
       $result = phutil_utf8ize($raw_patch);
     }
 
     if ($result) {
       $result = "PATCH\n\n{$result}\n";
     }
     $body->addRawSection($result);
   }
 
   private function renderInlineCommentsForMail(
     PhabricatorLiskDAO $object,
     array $inline_xactions) {
 
     $inlines = mpull($inline_xactions, 'getComment');
 
     $block = array();
 
     $path_map = id(new DiffusionPathQuery())
       ->withPathIDs(mpull($inlines, 'getPathID'))
       ->execute();
     $path_map = ipull($path_map, 'path', 'id');
 
     foreach ($inlines as $inline) {
       $path = idx($path_map, $inline->getPathID());
       if ($path === null) {
         continue;
       }
 
       $start = $inline->getLineNumber();
       $len   = $inline->getLineLength();
       if ($len) {
         $range = $start.'-'.($start + $len);
       } else {
         $range = $start;
       }
 
       $content = $inline->getContent();
       $block[] = "{$path}:{$range} {$content}";
     }
 
     return implode("\n", $block);
   }
 
   public function getMailTagsMap() {
     return array(
       PhabricatorAuditTransaction::MAILTAG_COMMIT =>
         pht('A commit is created.'),
       PhabricatorAuditTransaction::MAILTAG_ACTION_CONCERN =>
         pht('A commit has a concerned raised against it.'),
       PhabricatorAuditTransaction::MAILTAG_ACTION_ACCEPT =>
         pht('A commit is accepted.'),
       PhabricatorAuditTransaction::MAILTAG_ACTION_RESIGN =>
         pht('A commit has an auditor resign.'),
       PhabricatorAuditTransaction::MAILTAG_ACTION_CLOSE =>
         pht('A commit is closed.'),
       PhabricatorAuditTransaction::MAILTAG_ADD_AUDITORS =>
         pht('A commit has auditors added.'),
       PhabricatorAuditTransaction::MAILTAG_ADD_CCS =>
         pht("A commit's subscribers change."),
       PhabricatorAuditTransaction::MAILTAG_PROJECTS =>
         pht("A commit's projects change."),
       PhabricatorAuditTransaction::MAILTAG_COMMENT =>
         pht('Someone comments on a commit.'),
       PhabricatorAuditTransaction::MAILTAG_OTHER =>
         pht('Other commit activity not listed above occurs.'),
     );
   }
 
   protected function shouldApplyHeraldRules(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorAuditTransaction::TYPE_COMMIT:
           $repository = $object->getRepository();
           if (!$repository->shouldPublish()) {
             return false;
           }
           return true;
         default:
           break;
       }
     }
     return parent::shouldApplyHeraldRules($object, $xactions);
   }
 
   protected function buildHeraldAdapter(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return id(new HeraldCommitAdapter())
       ->setObject($object);
   }
 
   protected function didApplyHeraldRules(
     PhabricatorLiskDAO $object,
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
 
     $limit = self::MAX_FILES_SHOWN_IN_EMAIL;
     $files = $adapter->loadAffectedPaths();
     sort($files);
     if (count($files) > $limit) {
       array_splice($files, $limit);
       $files[] = pht(
         '(This commit affected more than %d files. Only %d are shown here '.
         'and additional ones are truncated.)',
         $limit,
         $limit);
     }
     $this->affectedFiles = implode("\n", $files);
 
     return array();
   }
 
   private function isCommitMostlyImported(PhabricatorLiskDAO $object) {
     $has_message = PhabricatorRepositoryCommit::IMPORTED_MESSAGE;
     $has_changes = PhabricatorRepositoryCommit::IMPORTED_CHANGE;
 
     // Don't publish feed stories or email about events which occur during
     // import. In particular, this affects tasks being attached when they are
     // closed by "Fixes Txxxx" in a commit message. See T5851.
 
     $mask = ($has_message | $has_changes);
 
     return $object->isPartiallyImported($mask);
   }
 
 
   private function shouldPublishRepositoryActivity(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     // not every code path loads the repository so tread carefully
     // TODO: They should, and then we should simplify this.
     $repository = $object->getRepository($assert_attached = false);
     if ($repository != PhabricatorLiskDAO::ATTACHABLE) {
       if (!$repository->shouldPublish()) {
         return false;
       }
     }
 
     return $this->isCommitMostlyImported($object);
   }
 
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $this->shouldPublishRepositoryActivity($object, $xactions);
   }
 
   protected function shouldEnableMentions(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $this->shouldPublishRepositoryActivity($object, $xactions);
   }
 
   protected function shouldPublishFeedStory(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $this->shouldPublishRepositoryActivity($object, $xactions);
   }
 
   protected function getCustomWorkerState() {
     return array(
       'rawPatch' => $this->rawPatch,
       'affectedFiles' => $this->affectedFiles,
       'auditorPHIDs' => $this->auditorPHIDs,
     );
   }
 
   protected function getCustomWorkerStateEncoding() {
     return array(
       'rawPatch' => self::STORAGE_ENCODING_BINARY,
     );
   }
 
   protected function loadCustomWorkerState(array $state) {
     $this->rawPatch = idx($state, 'rawPatch');
     $this->affectedFiles = idx($state, 'affectedFiles');
     $this->auditorPHIDs = idx($state, 'auditorPHIDs');
     return $this;
   }
 
   protected function willPublish(PhabricatorLiskDAO $object, array $xactions) {
     return id(new DiffusionCommitQuery())
       ->setViewer($this->requireActor())
       ->withIDs(array($object->getID()))
       ->needAuditRequests(true)
       ->needCommitData(true)
       ->executeOne();
   }
 
 }
diff --git a/src/applications/differential/editor/DifferentialTransactionEditor.php b/src/applications/differential/editor/DifferentialTransactionEditor.php
index f3583438c8..cc29d69fe0 100644
--- a/src/applications/differential/editor/DifferentialTransactionEditor.php
+++ b/src/applications/differential/editor/DifferentialTransactionEditor.php
@@ -1,1728 +1,1740 @@
 <?php
 
 final class DifferentialTransactionEditor
   extends PhabricatorApplicationTransactionEditor {
 
   private $changedPriorToCommitURI;
   private $isCloseByCommit;
   private $repositoryPHIDOverride = false;
   private $didExpandInlineState = false;
   private $hasReviewTransaction = false;
   private $affectedPaths;
   private $firstBroadcast = false;
   private $wasDraft = false;
 
   public function getEditorApplicationClass() {
     return 'PhabricatorDifferentialApplication';
   }
 
   public function getEditorObjectsDescription() {
     return pht('Differential Revisions');
   }
 
   public function getCreateObjectTitle($author, $object) {
     return pht('%s created this revision.', $author);
   }
 
   public function getCreateObjectTitleForFeed($author, $object) {
     return pht('%s created %s.', $author, $object);
   }
 
   public function isFirstBroadcast() {
     return $this->firstBroadcast;
   }
 
   public function getDiffUpdateTransaction(array $xactions) {
     $type_update = DifferentialTransaction::TYPE_UPDATE;
 
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() == $type_update) {
         return $xaction;
       }
     }
 
     return null;
   }
 
   public function setIsCloseByCommit($is_close_by_commit) {
     $this->isCloseByCommit = $is_close_by_commit;
     return $this;
   }
 
   public function getIsCloseByCommit() {
     return $this->isCloseByCommit;
   }
 
   public function setChangedPriorToCommitURI($uri) {
     $this->changedPriorToCommitURI = $uri;
     return $this;
   }
 
   public function getChangedPriorToCommitURI() {
     return $this->changedPriorToCommitURI;
   }
 
   public function setRepositoryPHIDOverride($phid_or_null) {
     $this->repositoryPHIDOverride = $phid_or_null;
     return $this;
   }
 
   public function getTransactionTypes() {
     $types = parent::getTransactionTypes();
 
     $types[] = PhabricatorTransactions::TYPE_COMMENT;
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
     $types[] = PhabricatorTransactions::TYPE_INLINESTATE;
 
     $types[] = DifferentialTransaction::TYPE_INLINE;
     $types[] = DifferentialTransaction::TYPE_UPDATE;
 
     return $types;
   }
 
   protected function getCustomTransactionOldValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case DifferentialTransaction::TYPE_INLINE:
         return null;
       case DifferentialTransaction::TYPE_UPDATE:
         if ($this->getIsNewObject()) {
           return null;
         } else {
           return $object->getActiveDiff()->getPHID();
         }
     }
 
     return parent::getCustomTransactionOldValue($object, $xaction);
   }
 
   protected function getCustomTransactionNewValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case DifferentialTransaction::TYPE_UPDATE:
         return $xaction->getNewValue();
       case DifferentialTransaction::TYPE_INLINE:
         return null;
     }
 
     return parent::getCustomTransactionNewValue($object, $xaction);
   }
 
   protected function applyCustomInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case DifferentialTransaction::TYPE_INLINE:
         return;
       case DifferentialTransaction::TYPE_UPDATE:
         if (!$this->getIsCloseByCommit()) {
           if ($object->isNeedsRevision() ||
               $object->isChangePlanned() ||
               $object->isAbandoned()) {
             $object->setModernRevisionStatus(
               DifferentialRevisionStatus::NEEDS_REVIEW);
           }
         }
 
         $diff = $this->requireDiff($xaction->getNewValue());
 
         $this->updateRevisionLineCounts($object, $diff);
 
         if ($this->repositoryPHIDOverride !== false) {
           $object->setRepositoryPHID($this->repositoryPHIDOverride);
         } else {
           $object->setRepositoryPHID($diff->getRepositoryPHID());
         }
 
         $object->attachActiveDiff($diff);
         $object->setActiveDiffPHID($diff->getPHID());
         return;
     }
 
     return parent::applyCustomInternalTransaction($object, $xaction);
   }
 
   protected function expandTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_INLINESTATE:
           // If we have an "Inline State" transaction already, the caller
           // built it for us so we don't need to expand it again.
           $this->didExpandInlineState = true;
           break;
         case DifferentialRevisionAcceptTransaction::TRANSACTIONTYPE:
         case DifferentialRevisionRejectTransaction::TRANSACTIONTYPE:
         case DifferentialRevisionResignTransaction::TRANSACTIONTYPE:
           // If we have a review transaction, we'll skip marking the user
           // as "Commented" later. This should get cleaner after T10967.
           $this->hasReviewTransaction = true;
           break;
       }
     }
 
     $this->wasDraft = $object->isDraft();
 
     return parent::expandTransactions($object, $xactions);
   }
 
   protected function expandTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $results = parent::expandTransaction($object, $xaction);
 
     $actor = $this->getActor();
     $actor_phid = $this->getActingAsPHID();
     $type_edge = PhabricatorTransactions::TYPE_EDGE;
 
     $edge_ref_task = DifferentialRevisionHasTaskEdgeType::EDGECONST;
 
     $is_sticky_accept = PhabricatorEnv::getEnvConfig(
       'differential.sticky-accept');
 
     $downgrade_rejects = false;
     $downgrade_accepts = false;
     if ($this->getIsCloseByCommit()) {
       // Never downgrade reviewers when we're closing a revision after a
       // commit.
     } else {
       switch ($xaction->getTransactionType()) {
         case DifferentialTransaction::TYPE_UPDATE:
           $downgrade_rejects = true;
           if (!$is_sticky_accept) {
             // If "sticky accept" is disabled, also downgrade the accepts.
             $downgrade_accepts = true;
           }
           break;
         case DifferentialRevisionRequestReviewTransaction::TRANSACTIONTYPE:
           $downgrade_rejects = true;
           if ((!$is_sticky_accept) ||
               (!$object->isChangePlanned())) {
             // If the old state isn't "changes planned", downgrade the accepts.
             // This exception allows an accepted revision to go through
             // "Plan Changes" -> "Request Review" and return to "accepted" if
             // the author didn't update the revision, essentially undoing the
             // "Plan Changes".
             $downgrade_accepts = true;
           }
           break;
       }
     }
 
     $new_accept = DifferentialReviewerStatus::STATUS_ACCEPTED;
     $new_reject = DifferentialReviewerStatus::STATUS_REJECTED;
     $old_accept = DifferentialReviewerStatus::STATUS_ACCEPTED_OLDER;
     $old_reject = DifferentialReviewerStatus::STATUS_REJECTED_OLDER;
 
     $downgrade = array();
     if ($downgrade_accepts) {
       $downgrade[] = DifferentialReviewerStatus::STATUS_ACCEPTED;
     }
 
     if ($downgrade_rejects) {
       $downgrade[] = DifferentialReviewerStatus::STATUS_REJECTED;
     }
 
     if ($downgrade) {
       $void_type = DifferentialRevisionVoidTransaction::TRANSACTIONTYPE;
 
       $results[] = id(new DifferentialTransaction())
         ->setTransactionType($void_type)
         ->setIgnoreOnNoEffect(true)
         ->setNewValue($downgrade);
     }
 
     $is_commandeer = false;
     switch ($xaction->getTransactionType()) {
       case DifferentialTransaction::TYPE_UPDATE:
         if ($this->getIsCloseByCommit()) {
           // Don't bother with any of this if this update is a side effect of
           // commit detection.
           break;
         }
 
         // When a revision is updated and the diff comes from a branch named
         // "T123" or similar, automatically associate the commit with the
         // task that the branch names.
 
         $maniphest = 'PhabricatorManiphestApplication';
         if (PhabricatorApplication::isClassInstalled($maniphest)) {
           $diff = $this->requireDiff($xaction->getNewValue());
           $branch = $diff->getBranch();
 
           // No "$", to allow for branches like T123_demo.
           $match = null;
           if (preg_match('/^T(\d+)/i', $branch, $match)) {
             $task_id = $match[1];
             $tasks = id(new ManiphestTaskQuery())
               ->setViewer($this->getActor())
               ->withIDs(array($task_id))
               ->execute();
             if ($tasks) {
               $task = head($tasks);
               $task_phid = $task->getPHID();
 
               $results[] = id(new DifferentialTransaction())
                 ->setTransactionType($type_edge)
                 ->setMetadataValue('edge:type', $edge_ref_task)
                 ->setIgnoreOnNoEffect(true)
                 ->setNewValue(array('+' => array($task_phid => $task_phid)));
             }
           }
         }
         break;
 
       case DifferentialRevisionCommandeerTransaction::TRANSACTIONTYPE:
         $is_commandeer = true;
         break;
     }
 
     if ($is_commandeer) {
       $results[] = $this->newCommandeerReviewerTransaction($object);
     }
 
     if (!$this->didExpandInlineState) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_COMMENT:
         case DifferentialTransaction::TYPE_UPDATE:
         case DifferentialTransaction::TYPE_INLINE:
           $this->didExpandInlineState = true;
 
           $actor_phid = $this->getActingAsPHID();
           $actor_is_author = ($object->getAuthorPHID() == $actor_phid);
           if (!$actor_is_author) {
             break;
           }
 
           $state_map = PhabricatorTransactions::getInlineStateMap();
 
           $inlines = id(new DifferentialDiffInlineCommentQuery())
             ->setViewer($this->getActor())
             ->withRevisionPHIDs(array($object->getPHID()))
             ->withFixedStates(array_keys($state_map))
             ->execute();
 
           if (!$inlines) {
             break;
           }
 
           $old_value = mpull($inlines, 'getFixedState', 'getPHID');
           $new_value = array();
           foreach ($old_value as $key => $state) {
             $new_value[$key] = $state_map[$state];
           }
 
           $results[] = id(new DifferentialTransaction())
             ->setTransactionType(PhabricatorTransactions::TYPE_INLINESTATE)
             ->setIgnoreOnNoEffect(true)
             ->setOldValue($old_value)
             ->setNewValue($new_value);
           break;
       }
     }
 
     return $results;
   }
 
   protected function applyCustomExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case DifferentialTransaction::TYPE_INLINE:
         $reply = $xaction->getComment()->getReplyToComment();
         if ($reply && !$reply->getHasReplies()) {
           $reply->setHasReplies(1)->save();
         }
         return;
       case DifferentialTransaction::TYPE_UPDATE:
         // Now that we're inside the transaction, do a final check.
         $diff = $this->requireDiff($xaction->getNewValue());
 
         // TODO: It would be slightly cleaner to just revalidate this
         // transaction somehow using the same validation code, but that's
         // not easy to do at the moment.
 
         $revision_id = $diff->getRevisionID();
         if ($revision_id && ($revision_id != $object->getID())) {
           throw new Exception(
             pht(
               'Diff is already attached to another revision. You lost '.
               'a race?'));
         }
 
         // TODO: This can race with diff updates, particularly those from
         // Harbormaster. See discussion in T8650.
         $diff->setRevisionID($object->getID());
         $diff->save();
 
         // Update Harbormaster to set the containerPHID correctly for any
         // existing buildables. We may otherwise have buildables stuck with
         // the old (`null`) container.
 
         // TODO: This is a bit iffy, maybe we can find a cleaner approach?
         // In particular, this could (rarely) be overwritten by Harbormaster
         // workers.
         $table = new HarbormasterBuildable();
         $conn_w = $table->establishConnection('w');
         queryfx(
           $conn_w,
           'UPDATE %T SET containerPHID = %s WHERE buildablePHID = %s',
           $table->getTableName(),
           $object->getPHID(),
           $diff->getPHID());
 
         return;
     }
 
     return parent::applyCustomExternalTransaction($object, $xaction);
   }
 
   protected function applyBuiltinExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_INLINESTATE:
         $table = new DifferentialTransactionComment();
         $conn_w = $table->establishConnection('w');
         foreach ($xaction->getNewValue() as $phid => $state) {
           queryfx(
             $conn_w,
             'UPDATE %T SET fixedState = %s WHERE phid = %s',
             $table->getTableName(),
             $state,
             $phid);
         }
         break;
     }
 
     return parent::applyBuiltinExternalTransaction($object, $xaction);
   }
 
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     // Load the most up-to-date version of the revision and its reviewers,
     // so we don't need to try to deduce the state of reviewers by examining
     // all the changes made by the transactions. Then, update the reviewers
     // on the object to make sure we're acting on the current reviewer set
     // (and, for example, sending mail to the right people).
 
     $new_revision = id(new DifferentialRevisionQuery())
       ->setViewer($this->getActor())
       ->needReviewers(true)
       ->needActiveDiffs(true)
       ->withIDs(array($object->getID()))
       ->executeOne();
     if (!$new_revision) {
       throw new Exception(
         pht('Failed to load revision from transaction finalization.'));
     }
 
     $object->attachReviewers($new_revision->getReviewers());
     $object->attachActiveDiff($new_revision->getActiveDiff());
     $object->attachRepository($new_revision->getRepository());
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case DifferentialTransaction::TYPE_UPDATE:
           $diff = $this->requireDiff($xaction->getNewValue(), true);
 
           // Update these denormalized index tables when we attach a new
           // diff to a revision.
 
           $this->updateRevisionHashTable($object, $diff);
           $this->updateAffectedPathTable($object, $diff);
           break;
       }
     }
 
     $xactions = $this->updateReviewStatus($object, $xactions);
     $this->markReviewerComments($object, $xactions);
 
     return $xactions;
   }
 
   private function updateReviewStatus(
     DifferentialRevision $revision,
     array $xactions) {
 
     $was_accepted = $revision->isAccepted();
     $was_revision = $revision->isNeedsRevision();
     $was_review = $revision->isNeedsReview();
     if (!$was_accepted && !$was_revision && !$was_review) {
       // Revisions can't transition out of other statuses (like closed or
       // abandoned) as a side effect of reviewer status changes.
       return $xactions;
     }
 
     // Try to move a revision to "accepted". We look for:
     //
     //   - at least one accepting reviewer who is a user; and
     //   - no rejects; and
     //   - no rejects of older diffs; and
     //   - no blocking reviewers.
 
     $has_accepting_user = false;
     $has_rejecting_reviewer = false;
     $has_rejecting_older_reviewer = false;
     $has_blocking_reviewer = false;
 
     $active_diff = $revision->getActiveDiff();
     foreach ($revision->getReviewers() as $reviewer) {
       $reviewer_status = $reviewer->getReviewerStatus();
       switch ($reviewer_status) {
         case DifferentialReviewerStatus::STATUS_REJECTED:
           $active_phid = $active_diff->getPHID();
           if ($reviewer->isRejected($active_phid)) {
             $has_rejecting_reviewer = true;
           } else {
             $has_rejecting_older_reviewer = true;
           }
           break;
         case DifferentialReviewerStatus::STATUS_REJECTED_OLDER:
           $has_rejecting_older_reviewer = true;
           break;
         case DifferentialReviewerStatus::STATUS_BLOCKING:
           $has_blocking_reviewer = true;
           break;
         case DifferentialReviewerStatus::STATUS_ACCEPTED:
           if ($reviewer->isUser()) {
             $active_phid = $active_diff->getPHID();
             if ($reviewer->isAccepted($active_phid)) {
               $has_accepting_user = true;
             }
           }
           break;
       }
     }
 
     $new_status = null;
     if ($has_accepting_user &&
         !$has_rejecting_reviewer &&
         !$has_rejecting_older_reviewer &&
         !$has_blocking_reviewer) {
       $new_status = DifferentialRevisionStatus::ACCEPTED;
     } else if ($has_rejecting_reviewer) {
       // This isn't accepted, and there's at least one rejecting reviewer,
       // so the revision needs changes. This usually happens after a
       // "reject".
       $new_status = DifferentialRevisionStatus::NEEDS_REVISION;
     } else if ($was_accepted) {
       // This revision was accepted, but it no longer satisfies the
       // conditions for acceptance. This usually happens after an accepting
       // reviewer resigns or is removed.
       $new_status = DifferentialRevisionStatus::NEEDS_REVIEW;
     }
 
     if ($new_status === null) {
       return $xactions;
     }
 
     $old_status = $revision->getModernRevisionStatus();
     if ($new_status == $old_status) {
       return $xactions;
     }
 
     $xaction = id(new DifferentialTransaction())
       ->setTransactionType(
           DifferentialRevisionStatusTransaction::TRANSACTIONTYPE)
       ->setOldValue($old_status)
       ->setNewValue($new_status);
 
     $xaction = $this->populateTransaction($revision, $xaction)
       ->save();
     $xactions[] = $xaction;
 
     // Save the status adjustment we made earlier.
     $revision
       ->setModernRevisionStatus($new_status)
       ->save();
 
     return $xactions;
   }
 
 
   protected function validateTransaction(
     PhabricatorLiskDAO $object,
     $type,
     array $xactions) {
 
     $errors = parent::validateTransaction($object, $type, $xactions);
 
     $config_self_accept_key = 'differential.allow-self-accept';
     $allow_self_accept = PhabricatorEnv::getEnvConfig($config_self_accept_key);
 
     foreach ($xactions as $xaction) {
       switch ($type) {
         case DifferentialTransaction::TYPE_UPDATE:
           $diff = $this->loadDiff($xaction->getNewValue());
           if (!$diff) {
             $errors[] = new PhabricatorApplicationTransactionValidationError(
               $type,
               pht('Invalid'),
               pht('The specified diff does not exist.'),
               $xaction);
           } else if (($diff->getRevisionID()) &&
             ($diff->getRevisionID() != $object->getID())) {
             $errors[] = new PhabricatorApplicationTransactionValidationError(
               $type,
               pht('Invalid'),
               pht(
                 'You can not update this revision to the specified diff, '.
                 'because the diff is already attached to another revision.'),
               $xaction);
           }
           break;
       }
     }
 
     return $errors;
   }
 
   protected function sortTransactions(array $xactions) {
     $xactions = parent::sortTransactions($xactions);
 
     $head = array();
     $tail = array();
 
     foreach ($xactions as $xaction) {
       $type = $xaction->getTransactionType();
       if ($type == DifferentialTransaction::TYPE_INLINE) {
         $tail[] = $xaction;
       } else {
         $head[] = $xaction;
       }
     }
 
     return array_values(array_merge($head, $tail));
   }
 
   protected function shouldPublishFeedStory(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if (!$object->shouldBroadcast()) {
       return false;
     }
 
     return true;
   }
 
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if (!$object->shouldBroadcast()) {
       return false;
     }
 
     return true;
   }
 
   protected function getMailTo(PhabricatorLiskDAO $object) {
     $phids = array();
     $phids[] = $object->getAuthorPHID();
     foreach ($object->getReviewers() as $reviewer) {
       if ($reviewer->isResigned()) {
         continue;
       }
 
       $phids[] = $reviewer->getReviewerPHID();
     }
     return $phids;
   }
 
+  protected function newMailUnexpandablePHIDs(PhabricatorLiskDAO $object) {
+    $phids = array();
+
+    foreach ($object->getReviewers() as $reviewer) {
+      if ($reviewer->isResigned()) {
+        $phids[] = $reviewer->getReviewerPHID();
+      }
+    }
+
+    return $phids;
+  }
+
   protected function getMailAction(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $show_lines = false;
     if ($this->isFirstBroadcast()) {
       $action = pht('Request');
 
       $show_lines = true;
     } else {
       $action = parent::getMailAction($object, $xactions);
 
       $strongest = $this->getStrongestAction($object, $xactions);
       $type_update = DifferentialTransaction::TYPE_UPDATE;
       if ($strongest->getTransactionType() == $type_update) {
         $show_lines = true;
       }
     }
 
     if ($show_lines) {
       $count = new PhutilNumber($object->getLineCount());
       $action = pht('%s, %s line(s)', $action, $count);
     }
 
     return $action;
   }
 
   protected function getMailSubjectPrefix() {
     return PhabricatorEnv::getEnvConfig('metamta.differential.subject-prefix');
   }
 
   protected function getMailThreadID(PhabricatorLiskDAO $object) {
     // This is nonstandard, but retains threading with older messages.
     $phid = $object->getPHID();
     return "differential-rev-{$phid}-req";
   }
 
   protected function buildReplyHandler(PhabricatorLiskDAO $object) {
     return id(new DifferentialReplyHandler())
       ->setMailReceiver($object);
   }
 
   protected function buildMailTemplate(PhabricatorLiskDAO $object) {
     $id = $object->getID();
     $title = $object->getTitle();
     $subject = "D{$id}: {$title}";
 
     return id(new PhabricatorMetaMTAMail())
       ->setSubject($subject);
   }
 
   protected function getTransactionsForMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
     // If this is the first time we're sending mail about this revision, we
     // generate mail for all prior transactions, not just whatever is being
     // applied now. This gets the "added reviewers" lines and other relevant
     // information into the mail.
     if ($this->isFirstBroadcast()) {
       return $this->loadUnbroadcastTransactions($object);
     }
 
     return $xactions;
   }
 
   protected function buildMailBody(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $viewer = $this->requireActor();
 
     $body = new PhabricatorMetaMTAMailBody();
     $body->setViewer($this->requireActor());
 
     $revision_uri = PhabricatorEnv::getProductionURI('/D'.$object->getID());
 
     $this->addHeadersAndCommentsToMailBody(
       $body,
       $xactions,
       pht('View Revision'),
       $revision_uri);
 
     $type_inline = DifferentialTransaction::TYPE_INLINE;
 
     $inlines = array();
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() == $type_inline) {
         $inlines[] = $xaction;
       }
     }
 
     if ($inlines) {
       $this->appendInlineCommentsForMail($object, $inlines, $body);
     }
 
     $changed_uri = $this->getChangedPriorToCommitURI();
     if ($changed_uri) {
       $body->addLinkSection(
         pht('CHANGED PRIOR TO COMMIT'),
         $changed_uri);
     }
 
     $this->addCustomFieldsToMailBody($body, $object, $xactions);
 
     $body->addLinkSection(
       pht('REVISION DETAIL'),
       $revision_uri);
 
     $update_xaction = null;
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case DifferentialTransaction::TYPE_UPDATE:
           $update_xaction = $xaction;
           break;
       }
     }
 
     if ($update_xaction) {
       $diff = $this->requireDiff($update_xaction->getNewValue(), true);
 
       $body->addTextSection(
         pht('AFFECTED FILES'),
         $this->renderAffectedFilesForMail($diff));
 
       $config_key_inline = 'metamta.differential.inline-patches';
       $config_inline = PhabricatorEnv::getEnvConfig($config_key_inline);
 
       $config_key_attach = 'metamta.differential.attach-patches';
       $config_attach = PhabricatorEnv::getEnvConfig($config_key_attach);
 
       if ($config_inline || $config_attach) {
         $body_limit = PhabricatorEnv::getEnvConfig('metamta.email-body-limit');
 
         $patch = $this->buildPatchForMail($diff);
         if ($config_inline) {
           $lines = substr_count($patch, "\n");
           $bytes = strlen($patch);
 
           // Limit the patch size to the smaller of 256 bytes per line or
           // the mail body limit. This prevents degenerate behavior for patches
           // with one line that is 10MB long. See T11748.
           $byte_limits = array();
           $byte_limits[] = (256 * $config_inline);
           $byte_limits[] = $body_limit;
           $byte_limit = min($byte_limits);
 
           $lines_ok = ($lines <= $config_inline);
           $bytes_ok = ($bytes <= $byte_limit);
 
           if ($lines_ok && $bytes_ok) {
             $this->appendChangeDetailsForMail($object, $diff, $patch, $body);
           } else {
             // TODO: Provide a helpful message about the patch being too
             // large or lengthy here.
           }
         }
 
         if ($config_attach) {
           // See T12033, T11767, and PHI55. This is a crude fix to stop the
           // major concrete problems that lackluster email size limits cause.
           if (strlen($patch) < $body_limit) {
             $name = pht('D%s.%s.patch', $object->getID(), $diff->getID());
             $mime_type = 'text/x-patch; charset=utf-8';
             $body->addAttachment(
               new PhabricatorMetaMTAAttachment($patch, $name, $mime_type));
           }
         }
       }
     }
 
     return $body;
   }
 
   public function getMailTagsMap() {
     return array(
       DifferentialTransaction::MAILTAG_REVIEW_REQUEST =>
         pht('A revision is created.'),
       DifferentialTransaction::MAILTAG_UPDATED =>
         pht('A revision is updated.'),
       DifferentialTransaction::MAILTAG_COMMENT =>
         pht('Someone comments on a revision.'),
       DifferentialTransaction::MAILTAG_CLOSED =>
         pht('A revision is closed.'),
       DifferentialTransaction::MAILTAG_REVIEWERS =>
         pht("A revision's reviewers change."),
       DifferentialTransaction::MAILTAG_CC =>
         pht("A revision's CCs change."),
       DifferentialTransaction::MAILTAG_OTHER =>
         pht('Other revision activity not listed above occurs.'),
     );
   }
 
   protected function supportsSearch() {
     return true;
   }
 
   protected function expandCustomRemarkupBlockTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $changes,
     PhutilMarkupEngine $engine) {
 
     // For "Fixes ..." and "Depends on ...", we're only going to look at
     // content blocks which are part of the revision itself (like "Summary"
     // and  "Test Plan"), not comments.
     $content_parts = array();
     foreach ($changes as $change) {
       if ($change->getTransaction()->isCommentTransaction()) {
         continue;
       }
       $content_parts[] = $change->getNewValue();
     }
     if (!$content_parts) {
       return array();
     }
     $content_block = implode("\n\n", $content_parts);
     $task_map = array();
     $task_refs = id(new ManiphestCustomFieldStatusParser())
       ->parseCorpus($content_block);
     foreach ($task_refs as $match) {
       foreach ($match['monograms'] as $monogram) {
         $task_id = (int)trim($monogram, 'tT');
         $task_map[$task_id] = true;
       }
     }
 
     $rev_map = array();
     $rev_refs = id(new DifferentialCustomFieldDependsOnParser())
       ->parseCorpus($content_block);
     foreach ($rev_refs as $match) {
       foreach ($match['monograms'] as $monogram) {
         $rev_id = (int)trim($monogram, 'dD');
         $rev_map[$rev_id] = true;
       }
     }
 
     $edges = array();
     $task_phids = array();
     $rev_phids = array();
 
     if ($task_map) {
       $tasks = id(new ManiphestTaskQuery())
         ->setViewer($this->getActor())
         ->withIDs(array_keys($task_map))
         ->execute();
 
       if ($tasks) {
         $task_phids = mpull($tasks, 'getPHID', 'getPHID');
         $edge_related = DifferentialRevisionHasTaskEdgeType::EDGECONST;
         $edges[$edge_related] = $task_phids;
       }
     }
 
     if ($rev_map) {
       $revs = id(new DifferentialRevisionQuery())
         ->setViewer($this->getActor())
         ->withIDs(array_keys($rev_map))
         ->execute();
       $rev_phids = mpull($revs, 'getPHID', 'getPHID');
 
       // NOTE: Skip any write attempts if a user cleverly implies a revision
       // depends upon itself.
       unset($rev_phids[$object->getPHID()]);
 
       if ($revs) {
         $depends = DifferentialRevisionDependsOnRevisionEdgeType::EDGECONST;
         $edges[$depends] = $rev_phids;
       }
     }
 
     $revert_refs = id(new DifferentialCustomFieldRevertsParser())
       ->parseCorpus($content_block);
 
     $revert_monograms = array();
     foreach ($revert_refs as $match) {
       foreach ($match['monograms'] as $monogram) {
         $revert_monograms[] = $monogram;
       }
     }
 
     if ($revert_monograms) {
       $revert_objects = id(new PhabricatorObjectQuery())
         ->setViewer($this->getActor())
         ->withNames($revert_monograms)
         ->withTypes(
           array(
             DifferentialRevisionPHIDType::TYPECONST,
             PhabricatorRepositoryCommitPHIDType::TYPECONST,
           ))
         ->execute();
 
       $revert_phids = mpull($revert_objects, 'getPHID', 'getPHID');
 
       // Don't let an object revert itself, although other silly stuff like
       // cycles of objects reverting each other is not prevented.
       unset($revert_phids[$object->getPHID()]);
 
       $revert_type = DiffusionCommitRevertsCommitEdgeType::EDGECONST;
       $edges[$revert_type] = $revert_phids;
     } else {
       $revert_phids = array();
     }
 
     $this->setUnmentionablePHIDMap(
       array_merge(
         $task_phids,
         $rev_phids,
         $revert_phids));
 
     $result = array();
     foreach ($edges as $type => $specs) {
       $result[] = id(new DifferentialTransaction())
         ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
         ->setMetadataValue('edge:type', $type)
         ->setNewValue(array('+' => $specs));
     }
 
     return $result;
   }
 
   private function appendInlineCommentsForMail(
     PhabricatorLiskDAO $object,
     array $inlines,
     PhabricatorMetaMTAMailBody $body) {
 
     $section = id(new DifferentialInlineCommentMailView())
       ->setViewer($this->getActor())
       ->setInlines($inlines)
       ->buildMailSection();
 
     $header = pht('INLINE COMMENTS');
 
     $section_text = "\n".$section->getPlaintext();
 
     $style = array(
       'margin: 6px 0 12px 0;',
     );
 
     $section_html = phutil_tag(
       'div',
       array(
         'style' => implode(' ', $style),
       ),
       $section->getHTML());
 
     $body->addPlaintextSection($header, $section_text, false);
     $body->addHTMLSection($header, $section_html);
   }
 
   private function appendChangeDetailsForMail(
     PhabricatorLiskDAO $object,
     DifferentialDiff $diff,
     $patch,
     PhabricatorMetaMTAMailBody $body) {
 
     $section = id(new DifferentialChangeDetailMailView())
       ->setViewer($this->getActor())
       ->setDiff($diff)
       ->setPatch($patch)
       ->buildMailSection();
 
     $header = pht('CHANGE DETAILS');
 
     $section_text = "\n".$section->getPlaintext();
 
     $style = array(
       'margin: 6px 0 12px 0;',
     );
 
     $section_html = phutil_tag(
       'div',
       array(
         'style' => implode(' ', $style),
       ),
       $section->getHTML());
 
     $body->addPlaintextSection($header, $section_text, false);
     $body->addHTMLSection($header, $section_html);
   }
 
   private function loadDiff($phid, $need_changesets = false) {
     $query = id(new DifferentialDiffQuery())
       ->withPHIDs(array($phid))
       ->setViewer($this->getActor());
 
     if ($need_changesets) {
       $query->needChangesets(true);
     }
 
     return $query->executeOne();
   }
 
   private function requireDiff($phid, $need_changesets = false) {
     $diff = $this->loadDiff($phid, $need_changesets);
     if (!$diff) {
       throw new Exception(pht('Diff "%s" does not exist!', $phid));
     }
 
     return $diff;
   }
 
 /* -(  Herald Integration  )------------------------------------------------- */
 
   protected function shouldApplyHeraldRules(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return true;
   }
 
   protected function didApplyHeraldRules(
     PhabricatorLiskDAO $object,
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
 
     $repository = $object->getRepository();
     if (!$repository) {
       return array();
     }
 
     if (!$this->affectedPaths) {
       return array();
     }
 
     $packages = PhabricatorOwnersPackage::loadAffectedPackages(
       $repository,
       $this->affectedPaths);
     if (!$packages) {
       return array();
     }
 
     // Remove packages that the revision author is an owner of. If you own
     // code, you don't need another owner to review it.
     $authority = id(new PhabricatorOwnersPackageQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withPHIDs(mpull($packages, 'getPHID'))
       ->withAuthorityPHIDs(array($object->getAuthorPHID()))
       ->execute();
     $authority = mpull($authority, null, 'getPHID');
 
     foreach ($packages as $key => $package) {
       $package_phid = $package->getPHID();
       if (isset($authority[$package_phid])) {
         unset($packages[$key]);
         continue;
       }
     }
 
     if (!$packages) {
       return array();
     }
 
     $auto_subscribe = array();
     $auto_review = array();
     $auto_block = array();
 
     foreach ($packages as $package) {
       switch ($package->getAutoReview()) {
         case PhabricatorOwnersPackage::AUTOREVIEW_SUBSCRIBE:
           $auto_subscribe[] = $package;
           break;
         case PhabricatorOwnersPackage::AUTOREVIEW_REVIEW:
           $auto_review[] = $package;
           break;
         case PhabricatorOwnersPackage::AUTOREVIEW_BLOCK:
           $auto_block[] = $package;
           break;
         case PhabricatorOwnersPackage::AUTOREVIEW_NONE:
         default:
           break;
       }
     }
 
     $owners_phid = id(new PhabricatorOwnersApplication())
       ->getPHID();
 
     $xactions = array();
     if ($auto_subscribe) {
       $xactions[] = $object->getApplicationTransactionTemplate()
         ->setAuthorPHID($owners_phid)
         ->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS)
         ->setNewValue(
           array(
             '+' => mpull($auto_subscribe, 'getPHID'),
           ));
     }
 
     $specs = array(
       array($auto_review, false),
       array($auto_block, true),
     );
 
     foreach ($specs as $spec) {
       list($reviewers, $blocking) = $spec;
       if (!$reviewers) {
         continue;
       }
 
       $phids = mpull($reviewers, 'getPHID');
       $xaction = $this->newAutoReviewTransaction($object, $phids, $blocking);
       if ($xaction) {
         $xactions[] = $xaction;
       }
     }
 
     return $xactions;
   }
 
   private function newAutoReviewTransaction(
     PhabricatorLiskDAO $object,
     array $phids,
     $is_blocking) {
 
     // TODO: This is substantially similar to DifferentialReviewersHeraldAction
     // and both are needlessly complex. This logic should live in the normal
     // transaction application pipeline. See T10967.
 
     $reviewers = $object->getReviewers();
     $reviewers = mpull($reviewers, null, 'getReviewerPHID');
 
     if ($is_blocking) {
       $new_status = DifferentialReviewerStatus::STATUS_BLOCKING;
     } else {
       $new_status = DifferentialReviewerStatus::STATUS_ADDED;
     }
 
     $new_strength = DifferentialReviewerStatus::getStatusStrength(
       $new_status);
 
     $current = array();
     foreach ($phids as $phid) {
       if (!isset($reviewers[$phid])) {
         continue;
       }
 
       // If we're applying a stronger status (usually, upgrading a reviewer
       // into a blocking reviewer), skip this check so we apply the change.
       $old_strength = DifferentialReviewerStatus::getStatusStrength(
         $reviewers[$phid]->getReviewerStatus());
       if ($old_strength <= $new_strength) {
         continue;
       }
 
       $current[] = $phid;
     }
 
     $phids = array_diff($phids, $current);
 
     if (!$phids) {
       return null;
     }
 
     $phids = array_fuse($phids);
 
     $value = array();
     foreach ($phids as $phid) {
       if ($is_blocking) {
         $value[] = 'blocking('.$phid.')';
       } else {
         $value[] = $phid;
       }
     }
 
     $owners_phid = id(new PhabricatorOwnersApplication())
       ->getPHID();
 
     $reviewers_type = DifferentialRevisionReviewersTransaction::TRANSACTIONTYPE;
 
     return $object->getApplicationTransactionTemplate()
       ->setAuthorPHID($owners_phid)
       ->setTransactionType($reviewers_type)
       ->setNewValue(
         array(
           '+' => $value,
         ));
   }
 
   protected function buildHeraldAdapter(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $revision = id(new DifferentialRevisionQuery())
       ->setViewer($this->getActor())
       ->withPHIDs(array($object->getPHID()))
       ->needActiveDiffs(true)
       ->needReviewers(true)
       ->executeOne();
     if (!$revision) {
       throw new Exception(
         pht('Failed to load revision for Herald adapter construction!'));
     }
 
     $adapter = HeraldDifferentialRevisionAdapter::newLegacyAdapter(
       $revision,
       $revision->getActiveDiff());
 
     // If the object is still a draft, prevent "Send me an email" and other
     // similar rules from acting yet.
     if (!$object->shouldBroadcast()) {
       $adapter->setForbiddenAction(
         HeraldMailableState::STATECONST,
         DifferentialHeraldStateReasons::REASON_DRAFT);
     }
 
     // If this edit didn't actually change the diff (for example, a user
     // edited the title or changed subscribers), prevent "Run build plan"
     // and other similar rules from acting yet, since the build results will
     // not (or, at least, should not) change unless the actual source changes.
     // We also don't run Differential builds if the update was caused by
     // discovering a commit, as the expectation is that Diffusion builds take
     // over once things land.
     $has_update = false;
     $has_commit = false;
 
     $type_update = DifferentialTransaction::TYPE_UPDATE;
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() != $type_update) {
         continue;
       }
 
       if ($xaction->getMetadataValue('isCommitUpdate')) {
         $has_commit = true;
       } else {
         $has_update = true;
       }
 
       break;
     }
 
     if ($has_commit) {
       $adapter->setForbiddenAction(
         HeraldBuildableState::STATECONST,
         DifferentialHeraldStateReasons::REASON_LANDED);
     } else if (!$has_update) {
       $adapter->setForbiddenAction(
         HeraldBuildableState::STATECONST,
         DifferentialHeraldStateReasons::REASON_UNCHANGED);
     }
 
     return $adapter;
   }
 
   /**
    * Update the table which links Differential revisions to paths they affect,
    * so Diffusion can efficiently find pending revisions for a given file.
    */
   private function updateAffectedPathTable(
     DifferentialRevision $revision,
     DifferentialDiff $diff) {
 
     $repository = $revision->getRepository();
     if (!$repository) {
       // The repository where the code lives is untracked.
       return;
     }
 
     $path_prefix = null;
 
     $local_root = $diff->getSourceControlPath();
     if ($local_root) {
       // We're in a working copy which supports subdirectory checkouts (e.g.,
       // SVN) so we need to figure out what prefix we should add to each path
       // (e.g., trunk/projects/example/) to get the absolute path from the
       // root of the repository. DVCS systems like Git and Mercurial are not
       // affected.
 
       // Normalize both paths and check if the repository root is a prefix of
       // the local root. If so, throw it away. Note that this correctly handles
       // the case where the remote path is "/".
       $local_root = id(new PhutilURI($local_root))->getPath();
       $local_root = rtrim($local_root, '/');
 
       $repo_root = id(new PhutilURI($repository->getRemoteURI()))->getPath();
       $repo_root = rtrim($repo_root, '/');
 
       if (!strncmp($repo_root, $local_root, strlen($repo_root))) {
         $path_prefix = substr($local_root, strlen($repo_root));
       }
     }
 
     $changesets = $diff->getChangesets();
     $paths = array();
     foreach ($changesets as $changeset) {
       $paths[] = $path_prefix.'/'.$changeset->getFilename();
     }
 
     // Save the affected paths; we'll use them later to query Owners. This
     // uses the un-expanded paths.
     $this->affectedPaths = $paths;
 
     // Mark this as also touching all parent paths, so you can see all pending
     // changes to any file within a directory.
     $all_paths = array();
     foreach ($paths as $local) {
       foreach (DiffusionPathIDQuery::expandPathToRoot($local) as $path) {
         $all_paths[$path] = true;
       }
     }
     $all_paths = array_keys($all_paths);
 
     $path_ids =
       PhabricatorRepositoryCommitChangeParserWorker::lookupOrCreatePaths(
         $all_paths);
 
     $table = new DifferentialAffectedPath();
     $conn_w = $table->establishConnection('w');
 
     $sql = array();
     foreach ($path_ids as $path_id) {
       $sql[] = qsprintf(
         $conn_w,
         '(%d, %d, %d, %d)',
         $repository->getID(),
         $path_id,
         time(),
         $revision->getID());
     }
 
     queryfx(
       $conn_w,
       'DELETE FROM %T WHERE revisionID = %d',
       $table->getTableName(),
       $revision->getID());
     foreach (array_chunk($sql, 256) as $chunk) {
       queryfx(
         $conn_w,
         'INSERT INTO %T (repositoryID, pathID, epoch, revisionID) VALUES %Q',
         $table->getTableName(),
         implode(', ', $chunk));
     }
   }
 
   /**
    * Update the table connecting revisions to DVCS local hashes, so we can
    * identify revisions by commit/tree hashes.
    */
   private function updateRevisionHashTable(
     DifferentialRevision $revision,
     DifferentialDiff $diff) {
 
     $vcs = $diff->getSourceControlSystem();
     if ($vcs == DifferentialRevisionControlSystem::SVN) {
       // Subversion has no local commit or tree hash information, so we don't
       // have to do anything.
       return;
     }
 
     $property = id(new DifferentialDiffProperty())->loadOneWhere(
       'diffID = %d AND name = %s',
       $diff->getID(),
       'local:commits');
     if (!$property) {
       return;
     }
 
     $hashes = array();
 
     $data = $property->getData();
     switch ($vcs) {
       case DifferentialRevisionControlSystem::GIT:
         foreach ($data as $commit) {
           $hashes[] = array(
             ArcanistDifferentialRevisionHash::HASH_GIT_COMMIT,
             $commit['commit'],
           );
           $hashes[] = array(
             ArcanistDifferentialRevisionHash::HASH_GIT_TREE,
             $commit['tree'],
           );
         }
         break;
       case DifferentialRevisionControlSystem::MERCURIAL:
         foreach ($data as $commit) {
           $hashes[] = array(
             ArcanistDifferentialRevisionHash::HASH_MERCURIAL_COMMIT,
             $commit['rev'],
           );
         }
         break;
     }
 
     $conn_w = $revision->establishConnection('w');
 
     $sql = array();
     foreach ($hashes as $info) {
       list($type, $hash) = $info;
       $sql[] = qsprintf(
         $conn_w,
         '(%d, %s, %s)',
         $revision->getID(),
         $type,
         $hash);
     }
 
     queryfx(
       $conn_w,
       'DELETE FROM %T WHERE revisionID = %d',
       ArcanistDifferentialRevisionHash::TABLE_NAME,
       $revision->getID());
 
     if ($sql) {
       queryfx(
         $conn_w,
         'INSERT INTO %T (revisionID, type, hash) VALUES %Q',
         ArcanistDifferentialRevisionHash::TABLE_NAME,
         implode(', ', $sql));
     }
   }
 
   private function renderAffectedFilesForMail(DifferentialDiff $diff) {
     $changesets = $diff->getChangesets();
 
     $filenames = mpull($changesets, 'getDisplayFilename');
     sort($filenames);
 
     $count = count($filenames);
     $max = 250;
     if ($count > $max) {
       $filenames = array_slice($filenames, 0, $max);
       $filenames[] = pht('(%d more files...)', ($count - $max));
     }
 
     return implode("\n", $filenames);
   }
 
   private function renderPatchHTMLForMail($patch) {
     return phutil_tag('pre',
       array('style' => 'font-family: monospace;'), $patch);
   }
 
   private function buildPatchForMail(DifferentialDiff $diff) {
     $format = PhabricatorEnv::getEnvConfig('metamta.differential.patch-format');
 
     return id(new DifferentialRawDiffRenderer())
       ->setViewer($this->getActor())
       ->setFormat($format)
       ->setChangesets($diff->getChangesets())
       ->buildPatch();
   }
 
   protected function willPublish(PhabricatorLiskDAO $object, array $xactions) {
     // Reload to pick up the active diff and reviewer status.
     return id(new DifferentialRevisionQuery())
       ->setViewer($this->getActor())
       ->needReviewers(true)
       ->needActiveDiffs(true)
       ->withIDs(array($object->getID()))
       ->executeOne();
   }
 
   protected function getCustomWorkerState() {
     return array(
       'changedPriorToCommitURI' => $this->changedPriorToCommitURI,
       'firstBroadcast' => $this->firstBroadcast,
     );
   }
 
   protected function loadCustomWorkerState(array $state) {
     $this->changedPriorToCommitURI = idx($state, 'changedPriorToCommitURI');
     $this->firstBroadcast = idx($state, 'firstBroadcast');
     return $this;
   }
 
   private function newCommandeerReviewerTransaction(
     DifferentialRevision $revision) {
 
     $actor_phid = $this->getActingAsPHID();
     $owner_phid = $revision->getAuthorPHID();
 
     // If the user is commandeering, add the previous owner as a
     // reviewer and remove the actor.
 
     $edits = array(
       '-' => array(
         $actor_phid,
       ),
       '+' => array(
         $owner_phid,
       ),
     );
 
     // NOTE: We're setting setIsCommandeerSideEffect() on this because normally
     // you can't add a revision's author as a reviewer, but this action swaps
     // them after validation executes.
 
     $xaction_type = DifferentialRevisionReviewersTransaction::TRANSACTIONTYPE;
 
     return id(new DifferentialTransaction())
       ->setTransactionType($xaction_type)
       ->setIgnoreOnNoEffect(true)
       ->setIsCommandeerSideEffect(true)
       ->setNewValue($edits);
   }
 
   public function getActiveDiff($object) {
     if ($this->getIsNewObject()) {
       return null;
     } else {
       return $object->getActiveDiff();
     }
   }
 
   /**
    * When a reviewer makes a comment, mark the last revision they commented
    * on.
    *
    * This allows us to show a hint to help authors and other reviewers quickly
    * distinguish between reviewers who have participated in the discussion and
    * reviewers who haven't been part of it.
    */
   private function markReviewerComments($object, array $xactions) {
     $acting_phid = $this->getActingAsPHID();
     if (!$acting_phid) {
       return;
     }
 
     $diff = $this->getActiveDiff($object);
     if (!$diff) {
       return;
     }
 
     $has_comment = false;
     foreach ($xactions as $xaction) {
       if ($xaction->hasComment()) {
         $has_comment = true;
         break;
       }
     }
 
     if (!$has_comment) {
       return;
     }
 
     $reviewer_table = new DifferentialReviewer();
     $conn = $reviewer_table->establishConnection('w');
 
     queryfx(
       $conn,
       'UPDATE %T SET lastCommentDiffPHID = %s
         WHERE revisionPHID = %s
         AND reviewerPHID = %s',
       $reviewer_table->getTableName(),
       $diff->getPHID(),
       $object->getPHID(),
       $acting_phid);
   }
 
   private function loadUnbroadcastTransactions($object) {
     $viewer = $this->requireActor();
 
     $xactions = id(new DifferentialTransactionQuery())
       ->setViewer($viewer)
       ->withObjectPHIDs(array($object->getPHID()))
       ->execute();
 
     return array_reverse($xactions);
   }
 
 
   protected function didApplyTransactions($object, array $xactions) {
     // In a moment, we're going to try to publish draft revisions which have
     // completed all their builds. However, we only want to do that if the
     // actor is either the revision author or an omnipotent user (generally,
     // the Harbormaster application).
 
     // If we let any actor publish the revision as a side effect of other
     // changes then an unlucky third party who innocently comments on the draft
     // can end up racing Harbormaster and promoting the revision. At best, this
     // is confusing. It can also run into validation problems with the "Request
     // Review" transaction. See PHI309 for some discussion.
     $author_phid = $object->getAuthorPHID();
     $viewer = $this->requireActor();
     $can_undraft =
       ($this->getActingAsPHID() === $author_phid) ||
       ($viewer->isOmnipotent());
 
     // If a draft revision has no outstanding builds and we're automatically
     // making drafts public after builds finish, make the revision public.
     if ($can_undraft) {
       $auto_undraft = !$object->getHoldAsDraft();
     } else {
       $auto_undraft = false;
     }
 
     if ($object->isDraft() && $auto_undraft) {
       $active_builds = $this->hasActiveBuilds($object);
       if (!$active_builds) {
         // When Harbormaster moves a revision out of the draft state, we
         // attribute the action to the revision author since this is more
         // natural and more useful.
 
         // Additionally, we change the acting PHID for the transaction set
         // to the author if it isn't already a user so that mail comes from
         // the natural author.
         $acting_phid = $this->getActingAsPHID();
         $user_type = PhabricatorPeopleUserPHIDType::TYPECONST;
         if (phid_get_type($acting_phid) != $user_type) {
           $this->setActingAsPHID($author_phid);
         }
 
         $xaction = $object->getApplicationTransactionTemplate()
           ->setAuthorPHID($author_phid)
           ->setTransactionType(
             DifferentialRevisionRequestReviewTransaction::TRANSACTIONTYPE)
           ->setNewValue(true);
 
         // If we're creating this revision and immediately moving it out of
         // the draft state, mark this as a create transaction so it gets
         // hidden in the timeline and mail, since it isn't interesting: it
         // is as though the draft phase never happened.
         if ($this->getIsNewObject()) {
           $xaction->setIsCreateTransaction(true);
         }
 
         // Queue this transaction and apply it separately after the current
         // batch of transactions finishes so that Herald can fire on the new
         // revision state. See T13027 for discussion.
         $this->queueTransaction($xaction);
       }
     }
 
     // If the revision is new or was a draft, and is no longer a draft, we
     // might be sending the first email about it.
 
     // This might mean it was created directly into a non-draft state, or
     // it just automatically undrafted after builds finished, or a user
     // explicitly promoted it out of the draft state with an action like
     // "Request Review".
 
     // If we haven't sent any email about it yet, mark this email as the first
     // email so the mail gets enriched with "SUMMARY" and "TEST PLAN".
 
     $is_new = $this->getIsNewObject();
     $was_draft = $this->wasDraft;
 
     if (!$object->isDraft() && ($was_draft || $is_new)) {
       if (!$object->getHasBroadcast()) {
         // Mark this as the first broadcast we're sending about the revision
         // so mail can generate specially.
         $this->firstBroadcast = true;
 
         $object
           ->setHasBroadcast(true)
           ->save();
       }
     }
 
     return $xactions;
   }
 
   private function hasActiveBuilds($object) {
     $viewer = $this->requireActor();
 
     $builds = $object->loadActiveBuilds($viewer);
     if (!$builds) {
       return false;
     }
 
     return true;
   }
 
   private function updateRevisionLineCounts(
     DifferentialRevision $revision,
     DifferentialDiff $diff) {
 
     $revision->setLineCount($diff->getLineCount());
 
     $conn = $revision->establishConnection('r');
 
     $row = queryfx_one(
       $conn,
       'SELECT SUM(addLines) A, SUM(delLines) D FROM %T
         WHERE diffID = %d',
       id(new DifferentialChangeset())->getTableName(),
       $diff->getID());
 
     if ($row) {
       $revision->setAddedLineCount((int)$row['A']);
       $revision->setRemovedLineCount((int)$row['D']);
     }
   }
 
 }
diff --git a/src/applications/differential/storage/DifferentialRevision.php b/src/applications/differential/storage/DifferentialRevision.php
index 938c588857..4591315207 100644
--- a/src/applications/differential/storage/DifferentialRevision.php
+++ b/src/applications/differential/storage/DifferentialRevision.php
@@ -1,1055 +1,1061 @@
 <?php
 
 final class DifferentialRevision extends DifferentialDAO
   implements
     PhabricatorTokenReceiverInterface,
     PhabricatorPolicyInterface,
     PhabricatorExtendedPolicyInterface,
     PhabricatorFlaggableInterface,
     PhrequentTrackableInterface,
     HarbormasterBuildableInterface,
     PhabricatorSubscribableInterface,
     PhabricatorCustomFieldInterface,
     PhabricatorApplicationTransactionInterface,
     PhabricatorMentionableInterface,
     PhabricatorDestructibleInterface,
     PhabricatorProjectInterface,
     PhabricatorFulltextInterface,
     PhabricatorFerretInterface,
     PhabricatorConduitResultInterface,
     PhabricatorDraftInterface {
 
   protected $title = '';
   protected $status;
 
   protected $summary = '';
   protected $testPlan = '';
 
   protected $authorPHID;
   protected $lastReviewerPHID;
 
   protected $lineCount = 0;
   protected $attached = array();
 
   protected $mailKey;
   protected $branchName;
   protected $repositoryPHID;
   protected $activeDiffPHID;
 
   protected $viewPolicy = PhabricatorPolicies::POLICY_USER;
   protected $editPolicy = PhabricatorPolicies::POLICY_USER;
   protected $properties = array();
 
   private $commits = self::ATTACHABLE;
   private $activeDiff = self::ATTACHABLE;
   private $diffIDs = self::ATTACHABLE;
   private $hashes = self::ATTACHABLE;
   private $repository = self::ATTACHABLE;
 
   private $reviewerStatus = self::ATTACHABLE;
   private $customFields = self::ATTACHABLE;
   private $drafts = array();
   private $flags = array();
   private $forceMap = array();
 
   const TABLE_COMMIT          = 'differential_commit';
 
   const RELATION_REVIEWER     = 'revw';
   const RELATION_SUBSCRIBED   = 'subd';
 
   const PROPERTY_CLOSED_FROM_ACCEPTED = 'wasAcceptedBeforeClose';
   const PROPERTY_DRAFT_HOLD = 'draft.hold';
   const PROPERTY_HAS_BROADCAST = 'draft.broadcast';
   const PROPERTY_LINES_ADDED = 'lines.added';
   const PROPERTY_LINES_REMOVED = 'lines.removed';
 
   public static function initializeNewRevision(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
       ->withClasses(array('PhabricatorDifferentialApplication'))
       ->executeOne();
 
     $view_policy = $app->getPolicy(
       DifferentialDefaultViewCapability::CAPABILITY);
 
     if (PhabricatorEnv::getEnvConfig('phabricator.show-prototypes')) {
       $initial_state = DifferentialRevisionStatus::DRAFT;
     } else {
       $initial_state = DifferentialRevisionStatus::NEEDS_REVIEW;
     }
 
     return id(new DifferentialRevision())
       ->setViewPolicy($view_policy)
       ->setAuthorPHID($actor->getPHID())
       ->attachRepository(null)
       ->attachActiveDiff(null)
       ->attachReviewers(array())
       ->setModernRevisionStatus($initial_state);
   }
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_SERIALIZATION => array(
         'attached'      => self::SERIALIZATION_JSON,
         'unsubscribed'  => self::SERIALIZATION_JSON,
         'properties' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'title' => 'text255',
         'status' => 'text32',
         'summary' => 'text',
         'testPlan' => 'text',
         'authorPHID' => 'phid?',
         'lastReviewerPHID' => 'phid?',
         'lineCount' => 'uint32?',
         'mailKey' => 'bytes40',
         'branchName' => 'text255?',
         'repositoryPHID' => 'phid?',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_phid' => null,
         'phid' => array(
           'columns' => array('phid'),
           'unique' => true,
         ),
         'authorPHID' => array(
           'columns' => array('authorPHID', 'status'),
         ),
         'repositoryPHID' => array(
           'columns' => array('repositoryPHID'),
         ),
         // If you (or a project you are a member of) is reviewing a significant
         // fraction of the revisions on an install, the result set of open
         // revisions may be smaller than the result set of revisions where you
         // are a reviewer. In these cases, this key is better than keys on the
         // edge table.
         'key_status' => array(
           'columns' => array('status', 'phid'),
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function setProperty($key, $value) {
     $this->properties[$key] = $value;
     return $this;
   }
 
   public function getProperty($key, $default = null) {
     return idx($this->properties, $key, $default);
   }
 
   public function hasRevisionProperty($key) {
     return array_key_exists($key, $this->properties);
   }
 
   public function getMonogram() {
     $id = $this->getID();
     return "D{$id}";
   }
 
   public function getURI() {
     return '/'.$this->getMonogram();
   }
 
   public function loadIDsByCommitPHIDs($phids) {
     if (!$phids) {
       return array();
     }
     $revision_ids = queryfx_all(
       $this->establishConnection('r'),
       'SELECT * FROM %T WHERE commitPHID IN (%Ls)',
       self::TABLE_COMMIT,
       $phids);
     return ipull($revision_ids, 'revisionID', 'commitPHID');
   }
 
   public function loadCommitPHIDs() {
     if (!$this->getID()) {
       return ($this->commits = array());
     }
 
     $commits = queryfx_all(
       $this->establishConnection('r'),
       'SELECT commitPHID FROM %T WHERE revisionID = %d',
       self::TABLE_COMMIT,
       $this->getID());
     $commits = ipull($commits, 'commitPHID');
 
     return ($this->commits = $commits);
   }
 
   public function getCommitPHIDs() {
     return $this->assertAttached($this->commits);
   }
 
   public function getActiveDiff() {
     // TODO: Because it's currently technically possible to create a revision
     // without an associated diff, we allow an attached-but-null active diff.
     // It would be good to get rid of this once we make diff-attaching
     // transactional.
 
     return $this->assertAttached($this->activeDiff);
   }
 
   public function attachActiveDiff($diff) {
     $this->activeDiff = $diff;
     return $this;
   }
 
   public function getDiffIDs() {
     return $this->assertAttached($this->diffIDs);
   }
 
   public function attachDiffIDs(array $ids) {
     rsort($ids);
     $this->diffIDs = array_values($ids);
     return $this;
   }
 
   public function attachCommitPHIDs(array $phids) {
     $this->commits = array_values($phids);
     return $this;
   }
 
   public function getAttachedPHIDs($type) {
     return array_keys(idx($this->attached, $type, array()));
   }
 
   public function setAttachedPHIDs($type, array $phids) {
     $this->attached[$type] = array_fill_keys($phids, array());
     return $this;
   }
 
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(
       DifferentialRevisionPHIDType::TYPECONST);
   }
 
   public function loadActiveDiff() {
     return id(new DifferentialDiff())->loadOneWhere(
       'revisionID = %d ORDER BY id DESC LIMIT 1',
       $this->getID());
   }
 
   public function save() {
     if (!$this->getMailKey()) {
       $this->mailKey = Filesystem::readRandomCharacters(40);
     }
     return parent::save();
   }
 
   public function getHashes() {
     return $this->assertAttached($this->hashes);
   }
 
   public function attachHashes(array $hashes) {
     $this->hashes = $hashes;
     return $this;
   }
 
   public function canReviewerForceAccept(
     PhabricatorUser $viewer,
     DifferentialReviewer $reviewer) {
 
     if (!$reviewer->isPackage()) {
       return false;
     }
 
     $map = $this->getReviewerForceAcceptMap($viewer);
     if (!$map) {
       return false;
     }
 
     if (isset($map[$reviewer->getReviewerPHID()])) {
       return true;
     }
 
     return false;
   }
 
   private function getReviewerForceAcceptMap(PhabricatorUser $viewer) {
     $fragment = $viewer->getCacheFragment();
 
     if (!array_key_exists($fragment, $this->forceMap)) {
       $map = $this->newReviewerForceAcceptMap($viewer);
       $this->forceMap[$fragment] = $map;
     }
 
     return $this->forceMap[$fragment];
   }
 
   private function newReviewerForceAcceptMap(PhabricatorUser $viewer) {
     $diff = $this->getActiveDiff();
     if (!$diff) {
       return null;
     }
 
     $repository_phid = $diff->getRepositoryPHID();
     if (!$repository_phid) {
       return null;
     }
 
     $paths = array();
 
     try {
       $changesets = $diff->getChangesets();
     } catch (Exception $ex) {
       $changesets = id(new DifferentialChangesetQuery())
         ->setViewer($viewer)
         ->withDiffs(array($diff))
         ->execute();
     }
 
     foreach ($changesets as $changeset) {
       $paths[] = $changeset->getOwnersFilename();
     }
 
     if (!$paths) {
       return null;
     }
 
     $reviewer_phids = array();
     foreach ($this->getReviewers() as $reviewer) {
       if (!$reviewer->isPackage()) {
         continue;
       }
 
       $reviewer_phids[] = $reviewer->getReviewerPHID();
     }
 
     if (!$reviewer_phids) {
       return null;
     }
 
     // Load all the reviewing packages which have control over some of the
     // paths in the change. These are packages which the actor may be able
     // to force-accept on behalf of.
     $control_query = id(new PhabricatorOwnersPackageQuery())
       ->setViewer($viewer)
       ->withStatuses(array(PhabricatorOwnersPackage::STATUS_ACTIVE))
       ->withPHIDs($reviewer_phids)
       ->withControl($repository_phid, $paths);
     $control_packages = $control_query->execute();
     if (!$control_packages) {
       return null;
     }
 
     // Load all the packages which have potential control over some of the
     // paths in the change and are owned by the actor. These are packages
     // which the actor may be able to use their authority over to gain the
     // ability to force-accept for other packages. This query doesn't apply
     // dominion rules yet, and we'll bypass those rules later on.
     $authority_query = id(new PhabricatorOwnersPackageQuery())
       ->setViewer($viewer)
       ->withStatuses(array(PhabricatorOwnersPackage::STATUS_ACTIVE))
       ->withAuthorityPHIDs(array($viewer->getPHID()))
       ->withControl($repository_phid, $paths);
     $authority_packages = $authority_query->execute();
     if (!$authority_packages) {
       return null;
     }
     $authority_packages = mpull($authority_packages, null, 'getPHID');
 
     // Build a map from each path in the revision to the reviewer packages
     // which control it.
     $control_map = array();
     foreach ($paths as $path) {
       $control_packages = $control_query->getControllingPackagesForPath(
         $repository_phid,
         $path);
 
       // Remove packages which the viewer has authority over. We don't need
       // to check these for force-accept because they can just accept them
       // normally.
       $control_packages = mpull($control_packages, null, 'getPHID');
       foreach ($control_packages as $phid => $control_package) {
         if (isset($authority_packages[$phid])) {
           unset($control_packages[$phid]);
         }
       }
 
       if (!$control_packages) {
         continue;
       }
 
       $control_map[$path] = $control_packages;
     }
 
     if (!$control_map) {
       return null;
     }
 
     // From here on out, we only care about paths which we have at least one
     // controlling package for.
     $paths = array_keys($control_map);
 
     // Now, build a map from each path to the packages which would control it
     // if there were no dominion rules.
     $authority_map = array();
     foreach ($paths as $path) {
       $authority_packages = $authority_query->getControllingPackagesForPath(
         $repository_phid,
         $path,
         $ignore_dominion = true);
 
       $authority_map[$path] = mpull($authority_packages, null, 'getPHID');
     }
 
     // For each path, find the most general package that the viewer has
     // authority over. For example, we'll prefer a package that owns "/" to a
     // package that owns "/src/".
     $force_map = array();
     foreach ($authority_map as $path => $package_map) {
       $path_fragments = PhabricatorOwnersPackage::splitPath($path);
       $fragment_count = count($path_fragments);
 
       // Find the package that we have authority over which has the most
       // general match for this path.
       $best_match = null;
       $best_package = null;
       foreach ($package_map as $package_phid => $package) {
         $package_paths = $package->getPathsForRepository($repository_phid);
         foreach ($package_paths as $package_path) {
 
           // NOTE: A strength of 0 means "no match". A strength of 1 means
           // that we matched "/", so we can not possibly find another stronger
           // match.
 
           $strength = $package_path->getPathMatchStrength(
             $path_fragments,
             $fragment_count);
           if (!$strength) {
             continue;
           }
 
           if ($strength < $best_match || !$best_package) {
             $best_match = $strength;
             $best_package = $package;
             if ($strength == 1) {
               break 2;
             }
           }
         }
       }
 
       if ($best_package) {
         $force_map[$path] = array(
           'strength' => $best_match,
           'package' => $best_package,
         );
       }
     }
 
     // For each path which the viewer owns a package for, find other packages
     // which that authority can be used to force-accept. Once we find a way to
     // force-accept a package, we don't need to keep looking.
     $has_control = array();
     foreach ($force_map as $path => $spec) {
       $path_fragments = PhabricatorOwnersPackage::splitPath($path);
       $fragment_count = count($path_fragments);
 
       $authority_strength = $spec['strength'];
 
       $control_packages = $control_map[$path];
       foreach ($control_packages as $control_phid => $control_package) {
         if (isset($has_control[$control_phid])) {
           continue;
         }
 
         $control_paths = $control_package->getPathsForRepository(
           $repository_phid);
         foreach ($control_paths as $control_path) {
           $strength = $control_path->getPathMatchStrength(
             $path_fragments,
             $fragment_count);
 
           if (!$strength) {
             continue;
           }
 
           if ($strength > $authority_strength) {
             $authority = $spec['package'];
             $has_control[$control_phid] = array(
               'authority' => $authority,
               'phid' => $authority->getPHID(),
             );
             break;
           }
         }
       }
     }
 
     // Return a map from packages which may be force accepted to the packages
     // which permit that forced acceptance.
     return ipull($has_control, 'phid');
   }
 
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
       PhabricatorPolicyCapability::CAN_EDIT,
     );
   }
 
   public function getPolicy($capability) {
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
         return $this->getEditPolicy();
     }
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $user) {
     // A revision's author (which effectively means "owner" after we added
     // commandeering) can always view and edit it.
     $author_phid = $this->getAuthorPHID();
     if ($author_phid) {
       if ($user->getPHID() == $author_phid) {
         return true;
       }
     }
 
     return false;
   }
 
   public function describeAutomaticCapability($capability) {
     $description = array(
       pht('The owner of a revision can always view and edit it.'),
     );
 
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         $description[] = pht(
           'If a revision belongs to a repository, other users must be able '.
           'to view the repository in order to view the revision.');
         break;
     }
 
     return $description;
   }
 
 
 /* -(  PhabricatorExtendedPolicyInterface  )--------------------------------- */
 
 
   public function getExtendedPolicy($capability, PhabricatorUser $viewer) {
     $extended = array();
 
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         $repository_phid = $this->getRepositoryPHID();
         $repository = $this->getRepository();
 
         // Try to use the object if we have it, since it will save us some
         // data fetching later on. In some cases, we might not have it.
         $repository_ref = nonempty($repository, $repository_phid);
         if ($repository_ref) {
           $extended[] = array(
             $repository_ref,
             PhabricatorPolicyCapability::CAN_VIEW,
           );
         }
         break;
     }
 
     return $extended;
   }
 
 
 /* -(  PhabricatorTokenReceiverInterface  )---------------------------------- */
 
 
   public function getUsersToNotifyOfTokenGiven() {
     return array(
       $this->getAuthorPHID(),
     );
   }
 
   public function getReviewers() {
     return $this->assertAttached($this->reviewerStatus);
   }
 
   public function attachReviewers(array $reviewers) {
     assert_instances_of($reviewers, 'DifferentialReviewer');
     $reviewers = mpull($reviewers, null, 'getReviewerPHID');
     $this->reviewerStatus = $reviewers;
     return $this;
   }
 
   public function getReviewerPHIDs() {
     $reviewers = $this->getReviewers();
     return mpull($reviewers, 'getReviewerPHID');
   }
 
   public function getReviewerPHIDsForEdit() {
     $reviewers = $this->getReviewers();
 
     $status_blocking = DifferentialReviewerStatus::STATUS_BLOCKING;
 
     $value = array();
     foreach ($reviewers as $reviewer) {
       $phid = $reviewer->getReviewerPHID();
       if ($reviewer->getReviewerStatus() == $status_blocking) {
         $value[] = 'blocking('.$phid.')';
       } else {
         $value[] = $phid;
       }
     }
 
     return $value;
   }
 
   public function getRepository() {
     return $this->assertAttached($this->repository);
   }
 
   public function attachRepository(PhabricatorRepository $repository = null) {
     $this->repository = $repository;
     return $this;
   }
 
   public function setModernRevisionStatus($status) {
     return $this->setStatus($status);
   }
 
   public function getModernRevisionStatus() {
     return $this->getStatus();
   }
 
   public function getLegacyRevisionStatus() {
     return $this->getStatusObject()->getLegacyKey();
   }
 
   public function isClosed() {
     return $this->getStatusObject()->isClosedStatus();
   }
 
   public function isAbandoned() {
     return $this->getStatusObject()->isAbandoned();
   }
 
   public function isAccepted() {
     return $this->getStatusObject()->isAccepted();
   }
 
   public function isNeedsReview() {
     return $this->getStatusObject()->isNeedsReview();
   }
 
   public function isNeedsRevision() {
     return $this->getStatusObject()->isNeedsRevision();
   }
 
   public function isChangePlanned() {
     return $this->getStatusObject()->isChangePlanned();
   }
 
   public function isPublished() {
     return $this->getStatusObject()->isPublished();
   }
 
   public function isDraft() {
     return $this->getStatusObject()->isDraft();
   }
 
   public function getStatusIcon() {
     return $this->getStatusObject()->getIcon();
   }
 
   public function getStatusDisplayName() {
     return $this->getStatusObject()->getDisplayName();
   }
 
   public function getStatusIconColor() {
     return $this->getStatusObject()->getIconColor();
   }
 
   public function getStatusObject() {
     $status = $this->getStatus();
     return DifferentialRevisionStatus::newForStatus($status);
   }
 
   public function getFlag(PhabricatorUser $viewer) {
     return $this->assertAttachedKey($this->flags, $viewer->getPHID());
   }
 
   public function attachFlag(
     PhabricatorUser $viewer,
     PhabricatorFlag $flag = null) {
     $this->flags[$viewer->getPHID()] = $flag;
     return $this;
   }
 
   public function getHasDraft(PhabricatorUser $viewer) {
     return $this->assertAttachedKey($this->drafts, $viewer->getCacheFragment());
   }
 
   public function attachHasDraft(PhabricatorUser $viewer, $has_draft) {
     $this->drafts[$viewer->getCacheFragment()] = $has_draft;
     return $this;
   }
 
   public function shouldBroadcast() {
     if (!$this->isDraft()) {
       return true;
     }
 
     return false;
   }
 
   public function getHoldAsDraft() {
     return $this->getProperty(self::PROPERTY_DRAFT_HOLD, false);
   }
 
   public function setHoldAsDraft($hold) {
     return $this->setProperty(self::PROPERTY_DRAFT_HOLD, $hold);
   }
 
   public function getHasBroadcast() {
     return $this->getProperty(self::PROPERTY_HAS_BROADCAST, false);
   }
 
   public function setHasBroadcast($has_broadcast) {
     return $this->setProperty(self::PROPERTY_HAS_BROADCAST, $has_broadcast);
   }
 
   public function setAddedLineCount($count) {
     return $this->setProperty(self::PROPERTY_LINES_ADDED, $count);
   }
 
   public function getAddedLineCount() {
     return $this->getProperty(self::PROPERTY_LINES_ADDED);
   }
 
   public function setRemovedLineCount($count) {
     return $this->setProperty(self::PROPERTY_LINES_REMOVED, $count);
   }
 
   public function getRemovedLineCount() {
     return $this->getProperty(self::PROPERTY_LINES_REMOVED);
   }
 
   public function loadActiveBuilds(PhabricatorUser $viewer) {
     $diff = $this->getActiveDiff();
 
     $buildables = id(new HarbormasterBuildableQuery())
       ->setViewer($viewer)
       ->withContainerPHIDs(array($this->getPHID()))
       ->withBuildablePHIDs(array($diff->getPHID()))
       ->withManualBuildables(false)
       ->execute();
     if (!$buildables) {
       return array();
     }
 
     return id(new HarbormasterBuildQuery())
       ->setViewer($viewer)
       ->withBuildablePHIDs(mpull($buildables, 'getPHID'))
       ->withAutobuilds(false)
       ->withBuildStatuses(
         array(
           HarbormasterBuildStatus::STATUS_INACTIVE,
           HarbormasterBuildStatus::STATUS_PENDING,
           HarbormasterBuildStatus::STATUS_BUILDING,
           HarbormasterBuildStatus::STATUS_FAILED,
           HarbormasterBuildStatus::STATUS_ABORTED,
           HarbormasterBuildStatus::STATUS_ERROR,
           HarbormasterBuildStatus::STATUS_PAUSED,
           HarbormasterBuildStatus::STATUS_DEADLOCKED,
         ))
       ->execute();
   }
 
 
 /* -(  HarbormasterBuildableInterface  )------------------------------------- */
 
 
   public function getHarbormasterBuildableDisplayPHID() {
     return $this->getHarbormasterContainerPHID();
   }
 
   public function getHarbormasterBuildablePHID() {
     return $this->loadActiveDiff()->getPHID();
   }
 
   public function getHarbormasterContainerPHID() {
     return $this->getPHID();
   }
 
   public function getHarbormasterPublishablePHID() {
     return $this->getPHID();
   }
 
   public function getBuildVariables() {
     return array();
   }
 
   public function getAvailableBuildVariables() {
     return array();
   }
 
 
 /* -(  PhabricatorSubscribableInterface  )----------------------------------- */
 
 
   public function isAutomaticallySubscribed($phid) {
     if ($phid == $this->getAuthorPHID()) {
       return true;
     }
 
     // TODO: This only happens when adding or removing CCs, and is safe from a
     // policy perspective, but the subscription pathway should have some
     // opportunity to load this data properly. For now, this is the only case
     // where implicit subscription is not an intrinsic property of the object.
     if ($this->reviewerStatus == self::ATTACHABLE) {
       $reviewers = id(new DifferentialRevisionQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->withPHIDs(array($this->getPHID()))
         ->needReviewers(true)
         ->executeOne()
         ->getReviewers();
     } else {
       $reviewers = $this->getReviewers();
     }
 
     foreach ($reviewers as $reviewer) {
-      if ($reviewer->getReviewerPHID() == $phid) {
-        return true;
+      if ($reviewer->getReviewerPHID() !== $phid) {
+        continue;
       }
+
+      if ($reviewer->isResigned()) {
+        continue;
+      }
+
+      return true;
     }
 
     return false;
   }
 
 
 /* -(  PhabricatorCustomFieldInterface  )------------------------------------ */
 
 
   public function getCustomFieldSpecificationForRole($role) {
     return PhabricatorEnv::getEnvConfig('differential.fields');
   }
 
   public function getCustomFieldBaseClass() {
     return 'DifferentialCustomField';
   }
 
   public function getCustomFields() {
     return $this->assertAttached($this->customFields);
   }
 
   public function attachCustomFields(PhabricatorCustomFieldAttachment $fields) {
     $this->customFields = $fields;
     return $this;
   }
 
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */
 
 
   public function getApplicationTransactionEditor() {
     return new DifferentialTransactionEditor();
   }
 
   public function getApplicationTransactionObject() {
     return $this;
   }
 
   public function getApplicationTransactionTemplate() {
     return new DifferentialTransaction();
   }
 
   public function willRenderTimeline(
     PhabricatorApplicationTransactionView $timeline,
     AphrontRequest $request) {
     $viewer = $request->getViewer();
 
     $render_data = $timeline->getRenderData();
     $left = $request->getInt('left', idx($render_data, 'left'));
     $right = $request->getInt('right', idx($render_data, 'right'));
 
     $diffs = id(new DifferentialDiffQuery())
       ->setViewer($request->getUser())
       ->withIDs(array($left, $right))
       ->execute();
     $diffs = mpull($diffs, null, 'getID');
     $left_diff = $diffs[$left];
     $right_diff = $diffs[$right];
 
     $old_ids = $request->getStr('old', idx($render_data, 'old'));
     $new_ids = $request->getStr('new', idx($render_data, 'new'));
     $old_ids = array_filter(explode(',', $old_ids));
     $new_ids = array_filter(explode(',', $new_ids));
 
     $type_inline = DifferentialTransaction::TYPE_INLINE;
     $changeset_ids = array_merge($old_ids, $new_ids);
     $inlines = array();
     foreach ($timeline->getTransactions() as $xaction) {
       if ($xaction->getTransactionType() == $type_inline) {
         $inlines[] = $xaction->getComment();
         $changeset_ids[] = $xaction->getComment()->getChangesetID();
       }
     }
 
     if ($changeset_ids) {
       $changesets = id(new DifferentialChangesetQuery())
         ->setViewer($request->getUser())
         ->withIDs($changeset_ids)
         ->execute();
       $changesets = mpull($changesets, null, 'getID');
     } else {
       $changesets = array();
     }
 
     foreach ($inlines as $key => $inline) {
       $inlines[$key] = DifferentialInlineComment::newFromModernComment(
         $inline);
     }
 
     $query = id(new DifferentialInlineCommentQuery())
       ->needHidden(true)
       ->setViewer($viewer);
 
     // NOTE: This is a bit sketchy: this method adjusts the inlines as a
     // side effect, which means it will ultimately adjust the transaction
     // comments and affect timeline rendering.
     $query->adjustInlinesForChangesets(
       $inlines,
       array_select_keys($changesets, $old_ids),
       array_select_keys($changesets, $new_ids),
       $this);
 
     return $timeline
       ->setChangesets($changesets)
       ->setRevision($this)
       ->setLeftDiff($left_diff)
       ->setRightDiff($right_diff);
   }
 
 
 /* -(  PhabricatorDestructibleInterface  )----------------------------------- */
 
 
   public function destroyObjectPermanently(
     PhabricatorDestructionEngine $engine) {
 
     $this->openTransaction();
       $diffs = id(new DifferentialDiffQuery())
         ->setViewer($engine->getViewer())
         ->withRevisionIDs(array($this->getID()))
         ->execute();
       foreach ($diffs as $diff) {
         $engine->destroyObject($diff);
       }
 
       $conn_w = $this->establishConnection('w');
 
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE revisionID = %d',
         self::TABLE_COMMIT,
         $this->getID());
 
       // we have to do paths a little differently as they do not have
       // an id or phid column for delete() to act on
       $dummy_path = new DifferentialAffectedPath();
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE revisionID = %d',
         $dummy_path->getTableName(),
         $this->getID());
 
       $this->delete();
     $this->saveTransaction();
   }
 
 
 /* -(  PhabricatorFulltextInterface  )--------------------------------------- */
 
 
   public function newFulltextEngine() {
     return new DifferentialRevisionFulltextEngine();
   }
 
 
 /* -(  PhabricatorFerretInterface  )----------------------------------------- */
 
 
   public function newFerretEngine() {
     return new DifferentialRevisionFerretEngine();
   }
 
 
 /* -(  PhabricatorConduitResultInterface  )---------------------------------- */
 
 
   public function getFieldSpecificationsForConduit() {
     return array(
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('title')
         ->setType('string')
         ->setDescription(pht('The revision title.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('authorPHID')
         ->setType('phid')
         ->setDescription(pht('Revision author PHID.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('status')
         ->setType('map<string, wild>')
         ->setDescription(pht('Information about revision status.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('repositoryPHID')
         ->setType('phid?')
         ->setDescription(pht('Revision repository PHID.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('diffPHID')
         ->setType('phid')
         ->setDescription(pht('Active diff PHID.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('summary')
         ->setType('string')
         ->setDescription(pht('Revision summary.')),
     );
   }
 
   public function getFieldValuesForConduit() {
     $status = $this->getStatusObject();
     $status_info = array(
       'value' => $status->getKey(),
       'name' => $status->getDisplayName(),
       'closed' => $status->isClosedStatus(),
       'color.ansi' => $status->getANSIColor(),
     );
 
     return array(
       'title' => $this->getTitle(),
       'authorPHID' => $this->getAuthorPHID(),
       'status' => $status_info,
       'repositoryPHID' => $this->getRepositoryPHID(),
       'diffPHID' => $this->getActiveDiffPHID(),
       'summary' => $this->getSummary(),
     );
   }
 
   public function getConduitSearchAttachments() {
     return array(
       id(new DifferentialReviewersSearchEngineAttachment())
         ->setAttachmentKey('reviewers'),
     );
   }
 
 
 /* -(  PhabricatorDraftInterface  )------------------------------------------ */
 
 
   public function newDraftEngine() {
     return new DifferentialRevisionDraftEngine();
   }
 
 }
diff --git a/src/applications/metamta/replyhandler/PhabricatorMailReplyHandler.php b/src/applications/metamta/replyhandler/PhabricatorMailReplyHandler.php
index b0ae2de494..f8dd784e3b 100644
--- a/src/applications/metamta/replyhandler/PhabricatorMailReplyHandler.php
+++ b/src/applications/metamta/replyhandler/PhabricatorMailReplyHandler.php
@@ -1,406 +1,436 @@
 <?php
 
 abstract class PhabricatorMailReplyHandler extends Phobject {
 
   private $mailReceiver;
   private $applicationEmail;
   private $actor;
   private $excludePHIDs = array();
+  private $unexpandablePHIDs = array();
 
   final public function setMailReceiver($mail_receiver) {
     $this->validateMailReceiver($mail_receiver);
     $this->mailReceiver = $mail_receiver;
     return $this;
   }
 
   final public function getMailReceiver() {
     return $this->mailReceiver;
   }
 
   public function setApplicationEmail(
     PhabricatorMetaMTAApplicationEmail $email) {
     $this->applicationEmail = $email;
     return $this;
   }
 
   public function getApplicationEmail() {
     return $this->applicationEmail;
   }
 
   final public function setActor(PhabricatorUser $actor) {
     $this->actor = $actor;
     return $this;
   }
 
   final public function getActor() {
     return $this->actor;
   }
 
   final public function setExcludeMailRecipientPHIDs(array $exclude) {
     $this->excludePHIDs = $exclude;
     return $this;
   }
 
   final public function getExcludeMailRecipientPHIDs() {
     return $this->excludePHIDs;
   }
 
+  public function setUnexpandablePHIDs(array $phids) {
+    $this->unexpandablePHIDs = $phids;
+    return $this;
+  }
+
+  public function getUnexpandablePHIDs() {
+    return $this->unexpandablePHIDs;
+  }
+
   abstract public function validateMailReceiver($mail_receiver);
   abstract public function getPrivateReplyHandlerEmailAddress(
     PhabricatorUser $user);
 
   public function getReplyHandlerDomain() {
     return PhabricatorEnv::getEnvConfig('metamta.reply-handler-domain');
   }
 
   abstract protected function receiveEmail(
     PhabricatorMetaMTAReceivedMail $mail);
 
   public function processEmail(PhabricatorMetaMTAReceivedMail $mail) {
     $this->dropEmptyMail($mail);
 
     return $this->receiveEmail($mail);
   }
 
   private function dropEmptyMail(PhabricatorMetaMTAReceivedMail $mail) {
     $body = $mail->getCleanTextBody();
     $attachments = $mail->getAttachments();
 
     if (strlen($body) || $attachments) {
       return;
     }
 
      // Only send an error email if the user is talking to just Phabricator.
      // We can assume if there is only one "To" address it is a Phabricator
      // address since this code is running and everything.
     $is_direct_mail = (count($mail->getToAddresses()) == 1) &&
                       (count($mail->getCCAddresses()) == 0);
 
     if ($is_direct_mail) {
       $status_code = MetaMTAReceivedMailStatus::STATUS_EMPTY;
     } else {
       $status_code = MetaMTAReceivedMailStatus::STATUS_EMPTY_IGNORED;
     }
 
     throw new PhabricatorMetaMTAReceivedMailProcessingException(
       $status_code,
       pht(
         'Your message does not contain any body text or attachments, so '.
         'Phabricator can not do anything useful with it. Make sure comment '.
         'text appears at the top of your message: quoted replies, inline '.
         'text, and signatures are discarded and ignored.'));
   }
 
   public function supportsPrivateReplies() {
     return (bool)$this->getReplyHandlerDomain() &&
            !$this->supportsPublicReplies();
   }
 
   public function supportsPublicReplies() {
     if (!PhabricatorEnv::getEnvConfig('metamta.public-replies')) {
       return false;
     }
 
     if (!$this->getReplyHandlerDomain()) {
       return false;
     }
 
     return (bool)$this->getPublicReplyHandlerEmailAddress();
   }
 
   final public function supportsReplies() {
     return $this->supportsPrivateReplies() ||
            $this->supportsPublicReplies();
   }
 
   public function getPublicReplyHandlerEmailAddress() {
     return null;
   }
 
   protected function getDefaultPublicReplyHandlerEmailAddress($prefix) {
 
     $receiver = $this->getMailReceiver();
     $receiver_id = $receiver->getID();
     $domain = $this->getReplyHandlerDomain();
 
     // We compute a hash using the object's own PHID to prevent an attacker
     // from blindly interacting with objects that they haven't ever received
     // mail about by just sending to D1@, D2@, etc...
     $hash = PhabricatorObjectMailReceiver::computeMailHash(
       $receiver->getMailKey(),
       $receiver->getPHID());
 
     $address = "{$prefix}{$receiver_id}+public+{$hash}@{$domain}";
     return $this->getSingleReplyHandlerPrefix($address);
   }
 
   protected function getSingleReplyHandlerPrefix($address) {
     $single_handle_prefix = PhabricatorEnv::getEnvConfig(
       'metamta.single-reply-handler-prefix');
     return ($single_handle_prefix)
       ? $single_handle_prefix.'+'.$address
       : $address;
   }
 
   protected function getDefaultPrivateReplyHandlerEmailAddress(
     PhabricatorUser $user,
     $prefix) {
 
     $receiver = $this->getMailReceiver();
     $receiver_id = $receiver->getID();
     $user_id = $user->getID();
     $hash = PhabricatorObjectMailReceiver::computeMailHash(
       $receiver->getMailKey(),
       $user->getPHID());
     $domain = $this->getReplyHandlerDomain();
 
     $address = "{$prefix}{$receiver_id}+{$user_id}+{$hash}@{$domain}";
     return $this->getSingleReplyHandlerPrefix($address);
   }
 
   final protected function enhanceBodyWithAttachments(
     $body,
     array $attachments) {
 
     if (!$attachments) {
       return $body;
     }
 
     $files = id(new PhabricatorFileQuery())
       ->setViewer($this->getActor())
       ->withPHIDs($attachments)
       ->execute();
 
     $output = array();
     $output[] = $body;
 
     // We're going to put all the non-images first in a list, then embed
     // the images.
     $head = array();
     $tail = array();
     foreach ($files as $file) {
       if ($file->isViewableImage()) {
         $tail[] = $file;
       } else {
         $head[] = $file;
       }
     }
 
     if ($head) {
       $list = array();
       foreach ($head as $file) {
         $list[] = '  - {'.$file->getMonogram().', layout=link}';
       }
       $output[] = implode("\n", $list);
     }
 
     if ($tail) {
       $list = array();
       foreach ($tail as $file) {
         $list[] = '{'.$file->getMonogram().'}';
       }
       $output[] = implode("\n\n", $list);
     }
 
     $output = implode("\n\n", $output);
 
     return rtrim($output);
   }
 
 
   /**
    * Produce a list of mail targets for a given to/cc list.
    *
    * Each target should be sent a separate email, and contains the information
    * required to generate it with appropriate permissions and configuration.
    *
    * @param list<phid> List of "To" PHIDs.
    * @param list<phid> List of "CC" PHIDs.
    * @return list<PhabricatorMailTarget> List of targets.
    */
   final public function getMailTargets(array $raw_to, array $raw_cc) {
     list($to, $cc) = $this->expandRecipientPHIDs($raw_to, $raw_cc);
     list($to, $cc) = $this->loadRecipientUsers($to, $cc);
     list($to, $cc) = $this->filterRecipientUsers($to, $cc);
 
     if (!$to && !$cc) {
       return array();
     }
 
     $template = id(new PhabricatorMailTarget())
       ->setRawToPHIDs($raw_to)
       ->setRawCCPHIDs($raw_cc);
 
     // Set the public reply address as the default, if one exists. We
     // might replace this with a private address later.
     if ($this->supportsPublicReplies()) {
       $reply_to = $this->getPublicReplyHandlerEmailAddress();
       if ($reply_to) {
         $template->setReplyTo($reply_to);
       }
     }
 
     $supports_private_replies = $this->supportsPrivateReplies();
     $mail_all = !PhabricatorEnv::getEnvConfig('metamta.one-mail-per-recipient');
     $targets = array();
     if ($mail_all) {
       $target = id(clone $template)
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->setToMap($to)
         ->setCCMap($cc);
 
       $targets[] = $target;
     } else {
       $map = $to + $cc;
 
       foreach ($map as $phid => $user) {
         // Preserve the original To/Cc information on the target.
         if (isset($to[$phid])) {
           $target_to = array($phid => $user);
           $target_cc = array();
         } else {
           $target_to = array();
           $target_cc = array($phid => $user);
         }
 
         $target = id(clone $template)
           ->setViewer($user)
           ->setToMap($target_to)
           ->setCCMap($target_cc);
 
         if ($supports_private_replies) {
           $reply_to = $this->getPrivateReplyHandlerEmailAddress($user);
           if ($reply_to) {
             $target->setReplyTo($reply_to);
           }
         }
 
         $targets[] = $target;
       }
     }
 
     return $targets;
   }
 
 
   /**
    * Expand lists of recipient PHIDs.
    *
    * This takes any compound recipients (like projects) and looks up all their
    * members.
    *
    * @param list<phid> List of To PHIDs.
    * @param list<phid> List of CC PHIDs.
    * @return pair<list<phid>, list<phid>> Expanded PHID lists.
    */
   private function expandRecipientPHIDs(array $to, array $cc) {
     $to_result = array();
     $cc_result = array();
 
+    // "Unexpandable" users have disengaged from an object (for example,
+    // by resigning from a revision).
+
+    // If such a user is still a direct recipient (for example, they're still
+    // on the Subscribers list) they're fair game, but group targets (like
+    // projects) will no longer include them when expanded.
+
+    $unexpandable = $this->getUnexpandablePHIDs();
+    $unexpandable = array_fuse($unexpandable);
+
     $all_phids = array_merge($to, $cc);
     if ($all_phids) {
       $map = id(new PhabricatorMetaMTAMemberQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->withPHIDs($all_phids)
         ->execute();
       foreach ($to as $phid) {
         foreach ($map[$phid] as $expanded) {
+          if ($expanded !== $phid) {
+            if (isset($unexpandable[$expanded])) {
+              continue;
+            }
+          }
           $to_result[$expanded] = $expanded;
         }
       }
       foreach ($cc as $phid) {
         foreach ($map[$phid] as $expanded) {
+          if ($expanded !== $phid) {
+            if (isset($unexpandable[$expanded])) {
+              continue;
+            }
+          }
           $cc_result[$expanded] = $expanded;
         }
       }
     }
 
     // Remove recipients from "CC" if they're also present in "To".
     $cc_result = array_diff_key($cc_result, $to_result);
 
     return array(array_values($to_result), array_values($cc_result));
   }
 
 
   /**
    * Load @{class:PhabricatorUser} objects for each recipient.
    *
    * Invalid recipients are dropped from the results.
    *
    * @param list<phid> List of To PHIDs.
    * @param list<phid> List of CC PHIDs.
    * @return pair<wild, wild> Maps from PHIDs to users.
    */
   private function loadRecipientUsers(array $to, array $cc) {
     $to_result = array();
     $cc_result = array();
 
     $all_phids = array_merge($to, $cc);
     if ($all_phids) {
       // We need user settings here because we'll check translations later
       // when generating mail.
       $users = id(new PhabricatorPeopleQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->withPHIDs($all_phids)
         ->needUserSettings(true)
         ->execute();
       $users = mpull($users, null, 'getPHID');
 
       foreach ($to as $phid) {
         if (isset($users[$phid])) {
           $to_result[$phid] = $users[$phid];
         }
       }
       foreach ($cc as $phid) {
         if (isset($users[$phid])) {
           $cc_result[$phid] = $users[$phid];
         }
       }
     }
 
     return array($to_result, $cc_result);
   }
 
 
   /**
    * Remove recipients who do not have permission to view the mail receiver.
    *
    * @param map<string, PhabricatorUser> Map of "To" users.
    * @param map<string, PhabricatorUser> Map of "CC" users.
    * @return pair<wild, wild> Filtered user maps.
    */
   private function filterRecipientUsers(array $to, array $cc) {
     $to_result = array();
     $cc_result = array();
 
     $all_users = $to + $cc;
     if ($all_users) {
       $can_see = array();
       $object = $this->getMailReceiver();
       foreach ($all_users as $phid => $user) {
         $visible = PhabricatorPolicyFilter::hasCapability(
           $user,
           $object,
           PhabricatorPolicyCapability::CAN_VIEW);
         if ($visible) {
           $can_see[$phid] = true;
         }
       }
 
       foreach ($to as $phid => $user) {
         if (!empty($can_see[$phid])) {
           $to_result[$phid] = $all_users[$phid];
         }
       }
 
       foreach ($cc as $phid => $user) {
         if (!empty($can_see[$phid])) {
           $cc_result[$phid] = $all_users[$phid];
         }
       }
     }
 
     return array($to_result, $cc_result);
   }
 
 }
diff --git a/src/applications/repository/storage/PhabricatorRepositoryAuditRequest.php b/src/applications/repository/storage/PhabricatorRepositoryAuditRequest.php
index ea86594d9e..e05820c825 100644
--- a/src/applications/repository/storage/PhabricatorRepositoryAuditRequest.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryAuditRequest.php
@@ -1,97 +1,106 @@
 <?php
 
 final class PhabricatorRepositoryAuditRequest
   extends PhabricatorRepositoryDAO
   implements PhabricatorPolicyInterface {
 
   protected $auditorPHID;
   protected $commitPHID;
   protected $auditReasons = array();
   protected $auditStatus;
 
   private $commit = self::ATTACHABLE;
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_TIMESTAMPS => false,
       self::CONFIG_SERIALIZATION => array(
         'auditReasons' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'auditStatus' => 'text64',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'commitPHID' => array(
           'columns' => array('commitPHID'),
         ),
         'auditorPHID' => array(
           'columns' => array('auditorPHID', 'auditStatus'),
         ),
         'key_unique' => array(
           'columns' => array('commitPHID', 'auditorPHID'),
           'unique' => true,
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function isUser() {
     $user_type = PhabricatorPeopleUserPHIDType::TYPECONST;
     return (phid_get_type($this->getAuditorPHID()) == $user_type);
   }
 
   public function attachCommit(PhabricatorRepositoryCommit $commit) {
     $this->commit = $commit;
     return $this;
   }
 
   public function getCommit() {
     return $this->assertAttached($this->commit);
   }
 
   public function isActiveAudit() {
     switch ($this->getAuditStatus()) {
       case PhabricatorAuditStatusConstants::NONE:
       case PhabricatorAuditStatusConstants::AUDIT_NOT_REQUIRED:
       case PhabricatorAuditStatusConstants::RESIGNED:
       case PhabricatorAuditStatusConstants::CLOSED:
       case PhabricatorAuditStatusConstants::CC:
         return false;
     }
 
     return true;
   }
 
   public function isInteresting() {
     switch ($this->getAuditStatus()) {
       case PhabricatorAuditStatusConstants::NONE:
       case PhabricatorAuditStatusConstants::AUDIT_NOT_REQUIRED:
         return false;
     }
 
     return true;
   }
 
+  public function isResigned() {
+    switch ($this->getAuditStatus()) {
+      case PhabricatorAuditStatusConstants::RESIGNED:
+        return true;
+    }
+
+    return false;
+  }
+
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
     );
   }
 
   public function getPolicy($capability) {
     return $this->getCommit()->getPolicy($capability);
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return $this->getCommit()->hasAutomaticCapability($capability, $viewer);
   }
 
   public function describeAutomaticCapability($capability) {
     return pht(
       'This audit is attached to a commit, and inherits its policies.');
   }
 }
diff --git a/src/applications/repository/storage/PhabricatorRepositoryCommit.php b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
index 31a06dcbd4..1c5998d583 100644
--- a/src/applications/repository/storage/PhabricatorRepositoryCommit.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
@@ -1,761 +1,762 @@
 <?php
 
 final class PhabricatorRepositoryCommit
   extends PhabricatorRepositoryDAO
   implements
     PhabricatorPolicyInterface,
     PhabricatorFlaggableInterface,
     PhabricatorProjectInterface,
     PhabricatorTokenReceiverInterface,
     PhabricatorSubscribableInterface,
     PhabricatorMentionableInterface,
     HarbormasterBuildableInterface,
     HarbormasterCircleCIBuildableInterface,
     HarbormasterBuildkiteBuildableInterface,
     PhabricatorCustomFieldInterface,
     PhabricatorApplicationTransactionInterface,
     PhabricatorFulltextInterface,
     PhabricatorFerretInterface,
     PhabricatorConduitResultInterface,
     PhabricatorDraftInterface {
 
   protected $repositoryID;
   protected $phid;
   protected $commitIdentifier;
   protected $epoch;
   protected $mailKey;
   protected $authorPHID;
   protected $auditStatus = PhabricatorAuditCommitStatusConstants::NONE;
   protected $summary = '';
   protected $importStatus = 0;
 
   const IMPORTED_MESSAGE = 1;
   const IMPORTED_CHANGE = 2;
   const IMPORTED_OWNERS = 4;
   const IMPORTED_HERALD = 8;
   const IMPORTED_ALL = 15;
 
   const IMPORTED_CLOSEABLE = 1024;
   const IMPORTED_UNREACHABLE = 2048;
 
   private $commitData = self::ATTACHABLE;
   private $audits = self::ATTACHABLE;
   private $repository = self::ATTACHABLE;
   private $customFields = self::ATTACHABLE;
   private $drafts = array();
   private $auditAuthorityPHIDs = array();
 
   public function attachRepository(PhabricatorRepository $repository) {
     $this->repository = $repository;
     return $this;
   }
 
   public function getRepository($assert_attached = true) {
     if ($assert_attached) {
       return $this->assertAttached($this->repository);
     }
     return $this->repository;
   }
 
   public function isPartiallyImported($mask) {
     return (($mask & $this->getImportStatus()) == $mask);
   }
 
   public function isImported() {
     return $this->isPartiallyImported(self::IMPORTED_ALL);
   }
 
   public function isUnreachable() {
     return $this->isPartiallyImported(self::IMPORTED_UNREACHABLE);
   }
 
   public function writeImportStatusFlag($flag) {
     return $this->adjustImportStatusFlag($flag, true);
   }
 
   public function clearImportStatusFlag($flag) {
     return $this->adjustImportStatusFlag($flag, false);
   }
 
   private function adjustImportStatusFlag($flag, $set) {
     $conn_w = $this->establishConnection('w');
     $table_name = $this->getTableName();
     $id = $this->getID();
 
     if ($set) {
       queryfx(
         $conn_w,
         'UPDATE %T SET importStatus = (importStatus | %d) WHERE id = %d',
         $table_name,
         $flag,
         $id);
 
       $this->setImportStatus($this->getImportStatus() | $flag);
     } else {
       queryfx(
         $conn_w,
         'UPDATE %T SET importStatus = (importStatus & ~%d) WHERE id = %d',
         $table_name,
         $flag,
         $id);
 
       $this->setImportStatus($this->getImportStatus() & ~$flag);
     }
 
     return $this;
   }
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID   => true,
       self::CONFIG_TIMESTAMPS => false,
       self::CONFIG_COLUMN_SCHEMA => array(
         'commitIdentifier' => 'text40',
         'mailKey' => 'bytes20',
         'authorPHID' => 'phid?',
         'auditStatus' => 'uint32',
         'summary' => 'text255',
         'importStatus' => 'uint32',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_phid' => null,
         'phid' => array(
           'columns' => array('phid'),
           'unique' => true,
         ),
         'repositoryID' => array(
           'columns' => array('repositoryID', 'importStatus'),
         ),
         'authorPHID' => array(
           'columns' => array('authorPHID', 'auditStatus', 'epoch'),
         ),
         'repositoryID_2' => array(
           'columns' => array('repositoryID', 'epoch'),
         ),
         'key_commit_identity' => array(
           'columns' => array('commitIdentifier', 'repositoryID'),
           'unique' => true,
         ),
         'key_epoch' => array(
           'columns' => array('epoch'),
         ),
         'key_author' => array(
           'columns' => array('authorPHID', 'epoch'),
         ),
       ),
       self::CONFIG_NO_MUTATE => array(
         'importStatus',
       ),
     ) + parent::getConfiguration();
   }
 
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(
       PhabricatorRepositoryCommitPHIDType::TYPECONST);
   }
 
   public function loadCommitData() {
     if (!$this->getID()) {
       return null;
     }
     return id(new PhabricatorRepositoryCommitData())->loadOneWhere(
       'commitID = %d',
       $this->getID());
   }
 
   public function attachCommitData(
     PhabricatorRepositoryCommitData $data = null) {
     $this->commitData = $data;
     return $this;
   }
 
   public function getCommitData() {
     return $this->assertAttached($this->commitData);
   }
 
   public function attachAudits(array $audits) {
     assert_instances_of($audits, 'PhabricatorRepositoryAuditRequest');
     $this->audits = $audits;
     return $this;
   }
 
   public function getAudits() {
     return $this->assertAttached($this->audits);
   }
 
   public function loadAndAttachAuditAuthority(
     PhabricatorUser $viewer,
     $actor_phid = null) {
 
     if ($actor_phid === null) {
       $actor_phid = $viewer->getPHID();
     }
 
     // TODO: This method is a little weird and sketchy, but worlds better than
     // what came before it. Eventually, this should probably live in a Query
     // class.
 
     // Figure out which requests the actor has authority over: these are user
     // requests where they are the auditor, and packages and projects they are
     // a member of.
 
     if (!$actor_phid) {
       $attach_key = $viewer->getCacheFragment();
       $phids = array();
     } else {
       $attach_key = $actor_phid;
       // At least currently, when modifying your own commits, you act only on
       // behalf of yourself, not your packages/projects -- the idea being that
       // you can't accept your own commits. This may change or depend on
       // config.
       $actor_is_author = ($actor_phid == $this->getAuthorPHID());
       if ($actor_is_author) {
         $phids = array($actor_phid);
       } else {
         $phids = array();
         $phids[$actor_phid] = true;
 
         $owned_packages = id(new PhabricatorOwnersPackageQuery())
           ->setViewer($viewer)
           ->withAuthorityPHIDs(array($actor_phid))
           ->execute();
         foreach ($owned_packages as $package) {
           $phids[$package->getPHID()] = true;
         }
 
         $projects = id(new PhabricatorProjectQuery())
           ->setViewer($viewer)
           ->withMemberPHIDs(array($actor_phid))
           ->execute();
         foreach ($projects as $project) {
           $phids[$project->getPHID()] = true;
         }
 
         $phids = array_keys($phids);
       }
     }
 
     $this->auditAuthorityPHIDs[$attach_key] = array_fuse($phids);
 
     return $this;
   }
 
   public function hasAuditAuthority(
     PhabricatorUser $viewer,
     PhabricatorRepositoryAuditRequest $audit,
     $actor_phid = null) {
 
     if ($actor_phid === null) {
       $actor_phid = $viewer->getPHID();
     }
 
     if (!$actor_phid) {
       $attach_key = $viewer->getCacheFragment();
     } else {
       $attach_key = $actor_phid;
     }
 
     $map = $this->assertAttachedKey($this->auditAuthorityPHIDs, $attach_key);
 
     if (!$actor_phid) {
       return false;
     }
 
     return isset($map[$audit->getAuditorPHID()]);
   }
 
   public function writeOwnersEdges(array $package_phids) {
     $src_phid = $this->getPHID();
     $edge_type = DiffusionCommitHasPackageEdgeType::EDGECONST;
 
     $editor = new PhabricatorEdgeEditor();
 
     $dst_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
       $src_phid,
       $edge_type);
 
     foreach ($dst_phids as $dst_phid) {
       $editor->removeEdge($src_phid, $edge_type, $dst_phid);
     }
 
     foreach ($package_phids as $package_phid) {
       $editor->addEdge($src_phid, $edge_type, $package_phid);
     }
 
     $editor->save();
 
     return $this;
   }
 
   public function getAuditorPHIDsForEdit() {
     $audits = $this->getAudits();
     return mpull($audits, 'getAuditorPHID');
   }
 
   public function save() {
     if (!$this->mailKey) {
       $this->mailKey = Filesystem::readRandomCharacters(20);
     }
     return parent::save();
   }
 
   public function delete() {
     $data = $this->loadCommitData();
     $audits = id(new PhabricatorRepositoryAuditRequest())
       ->loadAllWhere('commitPHID = %s', $this->getPHID());
     $this->openTransaction();
 
       if ($data) {
         $data->delete();
       }
       foreach ($audits as $audit) {
         $audit->delete();
       }
       $result = parent::delete();
 
     $this->saveTransaction();
     return $result;
   }
 
   public function getDateCreated() {
     // This is primarily to make analysis of commits with the Fact engine work.
     return $this->getEpoch();
   }
 
   public function getURI() {
     return '/'.$this->getMonogram();
   }
 
   /**
    * Synchronize a commit's overall audit status with the individual audit
    * triggers.
    */
   public function updateAuditStatus(array $requests) {
     assert_instances_of($requests, 'PhabricatorRepositoryAuditRequest');
 
     $any_concern = false;
     $any_accept = false;
     $any_need = false;
 
     foreach ($requests as $request) {
       switch ($request->getAuditStatus()) {
         case PhabricatorAuditStatusConstants::AUDIT_REQUIRED:
         case PhabricatorAuditStatusConstants::AUDIT_REQUESTED:
           $any_need = true;
           break;
         case PhabricatorAuditStatusConstants::ACCEPTED:
           $any_accept = true;
           break;
         case PhabricatorAuditStatusConstants::CONCERNED:
           $any_concern = true;
           break;
       }
     }
 
     $current_status = $this->getAuditStatus();
     $status_verify = PhabricatorAuditCommitStatusConstants::NEEDS_VERIFICATION;
 
     if ($any_concern) {
       if ($current_status == $status_verify) {
         // If the change is in "Needs Verification", we keep it there as
         // long as any auditors still have concerns.
         $status = $status_verify;
       } else {
         $status = PhabricatorAuditCommitStatusConstants::CONCERN_RAISED;
       }
     } else if ($any_accept) {
       if ($any_need) {
         $status = PhabricatorAuditCommitStatusConstants::PARTIALLY_AUDITED;
       } else {
         $status = PhabricatorAuditCommitStatusConstants::FULLY_AUDITED;
       }
     } else if ($any_need) {
       $status = PhabricatorAuditCommitStatusConstants::NEEDS_AUDIT;
     } else {
       $status = PhabricatorAuditCommitStatusConstants::NONE;
     }
 
     return $this->setAuditStatus($status);
   }
 
   public function getMonogram() {
     $repository = $this->getRepository();
     $callsign = $repository->getCallsign();
     $identifier = $this->getCommitIdentifier();
     if ($callsign !== null) {
       return "r{$callsign}{$identifier}";
     } else {
       $id = $repository->getID();
       return "R{$id}:{$identifier}";
     }
   }
 
   public function getDisplayName() {
     $repository = $this->getRepository();
     $identifier = $this->getCommitIdentifier();
     return $repository->formatCommitName($identifier);
   }
 
   /**
    * Return a local display name for use in the context of the containing
    * repository.
    *
    * In Git and Mercurial, this returns only a short hash, like "abcdef012345".
    * See @{method:getDisplayName} for a short name that always includes
    * repository context.
    *
    * @return string Short human-readable name for use inside a repository.
    */
   public function getLocalName() {
     $repository = $this->getRepository();
     $identifier = $this->getCommitIdentifier();
     return $repository->formatCommitName($identifier, $local = true);
   }
 
   public function renderAuthorLink($handles) {
     $author_phid = $this->getAuthorPHID();
     if ($author_phid && isset($handles[$author_phid])) {
       return $handles[$author_phid]->renderLink();
     }
 
     return $this->renderAuthorShortName($handles);
   }
 
   public function renderAuthorShortName($handles) {
     $author_phid = $this->getAuthorPHID();
     if ($author_phid && isset($handles[$author_phid])) {
       return $handles[$author_phid]->getName();
     }
 
     $data = $this->getCommitData();
     $name = $data->getAuthorName();
 
     $parsed = new PhutilEmailAddress($name);
     return nonempty($parsed->getDisplayName(), $parsed->getAddress());
   }
 
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
       PhabricatorPolicyCapability::CAN_EDIT,
     );
   }
 
   public function getPolicy($capability) {
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getRepository()->getPolicy($capability);
       case PhabricatorPolicyCapability::CAN_EDIT:
         return PhabricatorPolicies::POLICY_USER;
     }
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
     return $this->getRepository()->hasAutomaticCapability($capability, $viewer);
   }
 
   public function describeAutomaticCapability($capability) {
     return pht(
       'Commits inherit the policies of the repository they belong to.');
   }
 
 
 /* -(  PhabricatorTokenReceiverInterface  )---------------------------------- */
 
   public function getUsersToNotifyOfTokenGiven() {
     return array(
       $this->getAuthorPHID(),
     );
   }
 
 /* -( Stuff for serialization )---------------------------------------------- */
 
   /**
    * NOTE: this is not a complete serialization; only the 'protected' fields are
    * involved. This is due to ease of (ab)using the Lisk abstraction to get this
    * done, as well as complexity of the other fields.
    */
   public function toDictionary() {
     return array(
       'repositoryID' => $this->getRepositoryID(),
       'phid' =>  $this->getPHID(),
       'commitIdentifier' =>  $this->getCommitIdentifier(),
       'epoch' => $this->getEpoch(),
       'mailKey' => $this->getMailKey(),
       'authorPHID' => $this->getAuthorPHID(),
       'auditStatus' => $this->getAuditStatus(),
       'summary' => $this->getSummary(),
       'importStatus' => $this->getImportStatus(),
     );
   }
 
   public static function newFromDictionary(array $dict) {
     return id(new PhabricatorRepositoryCommit())
       ->loadFromArray($dict);
   }
 
 
 /* -(  HarbormasterBuildableInterface  )------------------------------------- */
 
 
   public function getHarbormasterBuildableDisplayPHID() {
     return $this->getHarbormasterBuildablePHID();
   }
 
   public function getHarbormasterBuildablePHID() {
     return $this->getPHID();
   }
 
   public function getHarbormasterContainerPHID() {
     return $this->getRepository()->getPHID();
   }
 
   public function getHarbormasterPublishablePHID() {
     return $this->getPHID();
   }
 
   public function getBuildVariables() {
     $results = array();
 
     $results['buildable.commit'] = $this->getCommitIdentifier();
     $repo = $this->getRepository();
 
     $results['repository.callsign'] = $repo->getCallsign();
     $results['repository.phid'] = $repo->getPHID();
     $results['repository.vcs'] = $repo->getVersionControlSystem();
     $results['repository.uri'] = $repo->getPublicCloneURI();
 
     return $results;
   }
 
   public function getAvailableBuildVariables() {
     return array(
       'buildable.commit' => pht('The commit identifier, if applicable.'),
       'repository.callsign' =>
         pht('The callsign of the repository in Phabricator.'),
       'repository.phid' =>
         pht('The PHID of the repository in Phabricator.'),
       'repository.vcs' =>
         pht('The version control system, either "svn", "hg" or "git".'),
       'repository.uri' =>
         pht('The URI to clone or checkout the repository from.'),
     );
   }
 
 
 /* -(  HarbormasterCircleCIBuildableInterface  )----------------------------- */
 
 
   public function getCircleCIGitHubRepositoryURI() {
     $repository = $this->getRepository();
 
     $commit_phid = $this->getPHID();
     $repository_phid = $repository->getPHID();
 
     if ($repository->isHosted()) {
       throw new Exception(
         pht(
           'This commit ("%s") is associated with a hosted repository '.
           '("%s"). Repositories must be imported from GitHub to be built '.
           'with CircleCI.',
           $commit_phid,
           $repository_phid));
     }
 
     $remote_uri = $repository->getRemoteURI();
     $path = HarbormasterCircleCIBuildStepImplementation::getGitHubPath(
       $remote_uri);
     if (!$path) {
       throw new Exception(
         pht(
           'This commit ("%s") is associated with a repository ("%s") that '.
           'with a remote URI ("%s") that does not appear to be hosted on '.
           'GitHub. Repositories must be hosted on GitHub to be built with '.
           'CircleCI.',
           $commit_phid,
           $repository_phid,
           $remote_uri));
     }
 
     return $remote_uri;
   }
 
   public function getCircleCIBuildIdentifierType() {
     return 'revision';
   }
 
   public function getCircleCIBuildIdentifier() {
     return $this->getCommitIdentifier();
   }
 
 
 /* -(  HarbormasterBuildkiteBuildableInterface  )---------------------------- */
 
 
   public function getBuildkiteBranch() {
     $viewer = PhabricatorUser::getOmnipotentUser();
     $repository = $this->getRepository();
 
     $branches = DiffusionQuery::callConduitWithDiffusionRequest(
       $viewer,
       DiffusionRequest::newFromDictionary(
         array(
           'repository' => $repository,
           'user' => $viewer,
         )),
       'diffusion.branchquery',
       array(
         'contains' => $this->getCommitIdentifier(),
         'repository' => $repository->getPHID(),
       ));
 
     if (!$branches) {
       throw new Exception(
         pht(
           'Commit "%s" is not an ancestor of any branch head, so it can not '.
           'be built with Buildkite.',
           $this->getCommitIdentifier()));
     }
 
     $branch = head($branches);
 
     return 'refs/heads/'.$branch['shortName'];
   }
 
   public function getBuildkiteCommit() {
     return $this->getCommitIdentifier();
   }
 
 
 /* -(  PhabricatorCustomFieldInterface  )------------------------------------ */
 
 
   public function getCustomFieldSpecificationForRole($role) {
     return PhabricatorEnv::getEnvConfig('diffusion.fields');
   }
 
   public function getCustomFieldBaseClass() {
     return 'PhabricatorCommitCustomField';
   }
 
   public function getCustomFields() {
     return $this->assertAttached($this->customFields);
   }
 
   public function attachCustomFields(PhabricatorCustomFieldAttachment $fields) {
     $this->customFields = $fields;
     return $this;
   }
 
 
 /* -(  PhabricatorSubscribableInterface  )----------------------------------- */
 
 
   public function isAutomaticallySubscribed($phid) {
 
     // TODO: This should also list auditors, but handling that is a bit messy
-    // right now because we are not guaranteed to have the data.
+    // right now because we are not guaranteed to have the data. (It should not
+    // include resigned auditors.)
 
     return ($phid == $this->getAuthorPHID());
   }
 
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */
 
 
   public function getApplicationTransactionEditor() {
     return new PhabricatorAuditEditor();
   }
 
   public function getApplicationTransactionObject() {
     return $this;
   }
 
   public function getApplicationTransactionTemplate() {
     return new PhabricatorAuditTransaction();
   }
 
   public function willRenderTimeline(
     PhabricatorApplicationTransactionView $timeline,
     AphrontRequest $request) {
 
     $xactions = $timeline->getTransactions();
 
     $path_ids = array();
     foreach ($xactions as $xaction) {
       if ($xaction->hasComment()) {
         $path_id = $xaction->getComment()->getPathID();
         if ($path_id) {
           $path_ids[] = $path_id;
         }
       }
     }
 
     $path_map = array();
     if ($path_ids) {
       $path_map = id(new DiffusionPathQuery())
         ->withPathIDs($path_ids)
         ->execute();
       $path_map = ipull($path_map, 'path', 'id');
     }
 
     return $timeline->setPathMap($path_map);
   }
 
 /* -(  PhabricatorFulltextInterface  )--------------------------------------- */
 
 
   public function newFulltextEngine() {
     return new DiffusionCommitFulltextEngine();
   }
 
 
 /* -(  PhabricatorFerretInterface  )----------------------------------------- */
 
 
   public function newFerretEngine() {
     return new DiffusionCommitFerretEngine();
   }
 
 
 /* -(  PhabricatorConduitResultInterface  )---------------------------------- */
 
   public function getFieldSpecificationsForConduit() {
     return array(
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('identifier')
         ->setType('string')
         ->setDescription(pht('The commit identifier.')),
     );
   }
 
   public function getFieldValuesForConduit() {
     return array(
       'identifier' => $this->getCommitIdentifier(),
     );
   }
 
   public function getConduitSearchAttachments() {
     return array();
   }
 
 
 /* -(  PhabricatorDraftInterface  )------------------------------------------ */
 
   public function newDraftEngine() {
     return new DiffusionCommitDraftEngine();
   }
 
   public function getHasDraft(PhabricatorUser $viewer) {
     return $this->assertAttachedKey($this->drafts, $viewer->getCacheFragment());
   }
 
   public function attachHasDraft(PhabricatorUser $viewer, $has_draft) {
     $this->drafts[$viewer->getCacheFragment()] = $has_draft;
     return $this;
   }
 
 }
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
index 6bb7679fdc..167aa05fed 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -1,4200 +1,4214 @@
 <?php
 
 /**
  *
  * Publishing and Managing State
  * ======
  *
  * After applying changes, the Editor queues a worker to publish mail, feed,
  * and notifications, and to perform other background work like updating search
  * indexes. This allows it to do this work without impacting performance for
  * users.
  *
  * When work is moved to the daemons, the Editor state is serialized by
  * @{method:getWorkerState}, then reloaded in a daemon process by
  * @{method:loadWorkerState}. **This is fragile.**
  *
  * State is not persisted into the daemons by default, because we can not send
  * arbitrary objects into the queue. This means the default behavior of any
  * state properties is to reset to their defaults without warning prior to
  * publishing.
  *
  * The easiest way to avoid this is to keep Editors stateless: the overwhelming
  * majority of Editors can be written statelessly. If you need to maintain
  * state, you can either:
  *
  *   - not require state to exist during publishing; or
  *   - pass state to the daemons by implementing @{method:getCustomWorkerState}
  *     and @{method:loadCustomWorkerState}.
  *
  * This architecture isn't ideal, and we may eventually split this class into
  * "Editor" and "Publisher" parts to make it more robust. See T6367 for some
  * discussion and context.
  *
  * @task mail Sending Mail
  * @task feed Publishing Feed Stories
  * @task search Search Index
  * @task files Integration with Files
  * @task workers Managing Workers
  */
 abstract class PhabricatorApplicationTransactionEditor
   extends PhabricatorEditor {
 
   private $contentSource;
   private $object;
   private $xactions;
 
   private $isNewObject;
   private $mentionedPHIDs;
   private $continueOnNoEffect;
   private $continueOnMissingFields;
   private $parentMessageID;
   private $heraldAdapter;
   private $heraldTranscript;
   private $subscribers;
   private $unmentionablePHIDMap = array();
   private $applicationEmail;
 
   private $isPreview;
   private $isHeraldEditor;
   private $isInverseEdgeEditor;
   private $actingAsPHID;
 
   private $heraldEmailPHIDs = array();
   private $heraldForcedEmailPHIDs = array();
   private $heraldHeader;
   private $mailToPHIDs = array();
   private $mailCCPHIDs = array();
   private $feedNotifyPHIDs = array();
   private $feedRelatedPHIDs = array();
   private $feedShouldPublish = false;
   private $mailShouldSend = false;
   private $modularTypes;
   private $silent;
   private $mustEncrypt;
   private $stampTemplates = array();
   private $mailStamps = array();
   private $oldTo = array();
   private $oldCC = array();
   private $mailRemovedPHIDs = array();
+  private $mailUnexpandablePHIDs = array();
 
   private $transactionQueue = array();
 
   const STORAGE_ENCODING_BINARY = 'binary';
 
   /**
    * Get the class name for the application this editor is a part of.
    *
    * Uninstalling the application will disable the editor.
    *
    * @return string Editor's application class name.
    */
   abstract public function getEditorApplicationClass();
 
 
   /**
    * Get a description of the objects this editor edits, like "Differential
    * Revisions".
    *
    * @return string Human readable description of edited objects.
    */
   abstract public function getEditorObjectsDescription();
 
 
   public function setActingAsPHID($acting_as_phid) {
     $this->actingAsPHID = $acting_as_phid;
     return $this;
   }
 
   public function getActingAsPHID() {
     if ($this->actingAsPHID) {
       return $this->actingAsPHID;
     }
     return $this->getActor()->getPHID();
   }
 
 
   /**
    * When the editor tries to apply transactions that have no effect, should
    * it raise an exception (default) or drop them and continue?
    *
    * Generally, you will set this flag for edits coming from "Edit" interfaces,
    * and leave it cleared for edits coming from "Comment" interfaces, so the
    * user will get a useful error if they try to submit a comment that does
    * nothing (e.g., empty comment with a status change that has already been
    * performed by another user).
    *
    * @param bool  True to drop transactions without effect and continue.
    * @return this
    */
   public function setContinueOnNoEffect($continue) {
     $this->continueOnNoEffect = $continue;
     return $this;
   }
 
   public function getContinueOnNoEffect() {
     return $this->continueOnNoEffect;
   }
 
 
   /**
    * When the editor tries to apply transactions which don't populate all of
    * an object's required fields, should it raise an exception (default) or
    * drop them and continue?
    *
    * For example, if a user adds a new required custom field (like "Severity")
    * to a task, all existing tasks won't have it populated. When users
    * manually edit existing tasks, it's usually desirable to have them provide
    * a severity. However, other operations (like batch editing just the
    * owner of a task) will fail by default.
    *
    * By setting this flag for edit operations which apply to specific fields
    * (like the priority, batch, and merge editors in Maniphest), these
    * operations can continue to function even if an object is outdated.
    *
    * @param bool  True to continue when transactions don't completely satisfy
    *              all required fields.
    * @return this
    */
   public function setContinueOnMissingFields($continue_on_missing_fields) {
     $this->continueOnMissingFields = $continue_on_missing_fields;
     return $this;
   }
 
   public function getContinueOnMissingFields() {
     return $this->continueOnMissingFields;
   }
 
 
   /**
    * Not strictly necessary, but reply handlers ideally set this value to
    * make email threading work better.
    */
   public function setParentMessageID($parent_message_id) {
     $this->parentMessageID = $parent_message_id;
     return $this;
   }
   public function getParentMessageID() {
     return $this->parentMessageID;
   }
 
   public function getIsNewObject() {
     return $this->isNewObject;
   }
 
   public function getMentionedPHIDs() {
     return $this->mentionedPHIDs;
   }
 
   public function setIsPreview($is_preview) {
     $this->isPreview = $is_preview;
     return $this;
   }
 
   public function getIsPreview() {
     return $this->isPreview;
   }
 
   public function setIsSilent($silent) {
     $this->silent = $silent;
     return $this;
   }
 
   public function getIsSilent() {
     return $this->silent;
   }
 
   public function getMustEncrypt() {
     return $this->mustEncrypt;
   }
 
   public function getHeraldRuleMonograms() {
     // Convert the stored "<123>, <456>" string into a list: "H123", "H456".
     $list = $this->heraldHeader;
     $list = preg_split('/[, ]+/', $list);
 
     foreach ($list as $key => $item) {
       $item = trim($item, '<>');
 
       if (!is_numeric($item)) {
         unset($list[$key]);
         continue;
       }
 
       $list[$key] = 'H'.$item;
     }
 
     return $list;
   }
 
   public function setIsInverseEdgeEditor($is_inverse_edge_editor) {
     $this->isInverseEdgeEditor = $is_inverse_edge_editor;
     return $this;
   }
 
   public function getIsInverseEdgeEditor() {
     return $this->isInverseEdgeEditor;
   }
 
   public function setIsHeraldEditor($is_herald_editor) {
     $this->isHeraldEditor = $is_herald_editor;
     return $this;
   }
 
   public function getIsHeraldEditor() {
     return $this->isHeraldEditor;
   }
 
   public function setUnmentionablePHIDMap(array $map) {
     $this->unmentionablePHIDMap = $map;
     return $this;
   }
 
   public function getUnmentionablePHIDMap() {
     return $this->unmentionablePHIDMap;
   }
 
   protected function shouldEnableMentions(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return true;
   }
 
   public function setApplicationEmail(
     PhabricatorMetaMTAApplicationEmail $email) {
     $this->applicationEmail = $email;
     return $this;
   }
 
   public function getApplicationEmail() {
     return $this->applicationEmail;
   }
 
   public function getTransactionTypesForObject($object) {
     $old = $this->object;
     try {
       $this->object = $object;
       $result = $this->getTransactionTypes();
       $this->object = $old;
     } catch (Exception $ex) {
       $this->object = $old;
       throw $ex;
     }
     return $result;
   }
 
   public function getTransactionTypes() {
     $types = array();
 
     $types[] = PhabricatorTransactions::TYPE_CREATE;
 
     if ($this->object instanceof PhabricatorEditEngineSubtypeInterface) {
       $types[] = PhabricatorTransactions::TYPE_SUBTYPE;
     }
 
     if ($this->object instanceof PhabricatorSubscribableInterface) {
       $types[] = PhabricatorTransactions::TYPE_SUBSCRIBERS;
     }
 
     if ($this->object instanceof PhabricatorCustomFieldInterface) {
       $types[] = PhabricatorTransactions::TYPE_CUSTOMFIELD;
     }
 
     if ($this->object instanceof HarbormasterBuildableInterface) {
       $types[] = PhabricatorTransactions::TYPE_BUILDABLE;
     }
 
     if ($this->object instanceof PhabricatorTokenReceiverInterface) {
       $types[] = PhabricatorTransactions::TYPE_TOKEN;
     }
 
     if ($this->object instanceof PhabricatorProjectInterface ||
         $this->object instanceof PhabricatorMentionableInterface) {
       $types[] = PhabricatorTransactions::TYPE_EDGE;
     }
 
     if ($this->object instanceof PhabricatorSpacesInterface) {
       $types[] = PhabricatorTransactions::TYPE_SPACE;
     }
 
     $template = $this->object->getApplicationTransactionTemplate();
     if ($template instanceof PhabricatorModularTransaction) {
       $xtypes = $template->newModularTransactionTypes();
       foreach ($xtypes as $xtype) {
         $types[] = $xtype->getTransactionTypeConstant();
       }
     }
 
     if ($template) {
       try {
         $comment = $template->getApplicationTransactionCommentObject();
       } catch (PhutilMethodNotImplementedException $ex) {
         $comment = null;
       }
 
       if ($comment) {
         $types[] = PhabricatorTransactions::TYPE_COMMENT;
       }
     }
 
     return $types;
   }
 
   private function adjustTransactionValues(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     if ($xaction->shouldGenerateOldValue()) {
       $old = $this->getTransactionOldValue($object, $xaction);
       $xaction->setOldValue($old);
     }
 
     $new = $this->getTransactionNewValue($object, $xaction);
     $xaction->setNewValue($new);
   }
 
   private function getTransactionOldValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $type = $xaction->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $xtype = clone $xtype;
       $xtype->setStorage($xaction);
       return $xtype->generateOldValue($object);
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_CREATE:
         return null;
       case PhabricatorTransactions::TYPE_SUBTYPE:
         return $object->getEditEngineSubtype();
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return array_values($this->subscribers);
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         if ($this->getIsNewObject()) {
           return null;
         }
         return $object->getViewPolicy();
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         if ($this->getIsNewObject()) {
           return null;
         }
         return $object->getEditPolicy();
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         if ($this->getIsNewObject()) {
           return null;
         }
         return $object->getJoinPolicy();
       case PhabricatorTransactions::TYPE_SPACE:
         if ($this->getIsNewObject()) {
           return null;
         }
 
         $space_phid = $object->getSpacePHID();
         if ($space_phid === null) {
           $default_space = PhabricatorSpacesNamespaceQuery::getDefaultSpace();
           if ($default_space) {
             $space_phid = $default_space->getPHID();
           }
         }
 
         return $space_phid;
       case PhabricatorTransactions::TYPE_EDGE:
         $edge_type = $xaction->getMetadataValue('edge:type');
         if (!$edge_type) {
           throw new Exception(
             pht(
               "Edge transaction has no '%s'!",
               'edge:type'));
         }
 
         $old_edges = array();
         if ($object->getPHID()) {
           $edge_src = $object->getPHID();
 
           $old_edges = id(new PhabricatorEdgeQuery())
             ->withSourcePHIDs(array($edge_src))
             ->withEdgeTypes(array($edge_type))
             ->needEdgeData(true)
             ->execute();
 
           $old_edges = $old_edges[$edge_src][$edge_type];
         }
         return $old_edges;
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         // NOTE: Custom fields have their old value pre-populated when they are
         // built by PhabricatorCustomFieldList.
         return $xaction->getOldValue();
       case PhabricatorTransactions::TYPE_COMMENT:
         return null;
       default:
         return $this->getCustomTransactionOldValue($object, $xaction);
     }
   }
 
   private function getTransactionNewValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $type = $xaction->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $xtype = clone $xtype;
       $xtype->setStorage($xaction);
       return $xtype->generateNewValue($object, $xaction->getNewValue());
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_CREATE:
         return null;
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return $this->getPHIDTransactionNewValue($xaction);
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
       case PhabricatorTransactions::TYPE_BUILDABLE:
       case PhabricatorTransactions::TYPE_TOKEN:
       case PhabricatorTransactions::TYPE_INLINESTATE:
       case PhabricatorTransactions::TYPE_SUBTYPE:
         return $xaction->getNewValue();
       case PhabricatorTransactions::TYPE_SPACE:
         $space_phid = $xaction->getNewValue();
         if (!strlen($space_phid)) {
           // If an install has no Spaces or the Spaces controls are not visible
           // to the viewer, we might end up with the empty string here instead
           // of a strict `null`, because some controller just used `getStr()`
           // to read the space PHID from the request.
           // Just make this work like callers might reasonably expect so we
           // don't need to handle this specially in every EditController.
           return $this->getActor()->getDefaultSpacePHID();
         } else {
           return $space_phid;
         }
       case PhabricatorTransactions::TYPE_EDGE:
         $new_value = $this->getEdgeTransactionNewValue($xaction);
 
         $edge_type = $xaction->getMetadataValue('edge:type');
         $type_project = PhabricatorProjectObjectHasProjectEdgeType::EDGECONST;
         if ($edge_type == $type_project) {
           $new_value = $this->applyProjectConflictRules($new_value);
         }
 
         return $new_value;
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->getNewValueFromApplicationTransactions($xaction);
       case PhabricatorTransactions::TYPE_COMMENT:
         return null;
       default:
         return $this->getCustomTransactionNewValue($object, $xaction);
     }
   }
 
   protected function getCustomTransactionOldValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     throw new Exception(pht('Capability not supported!'));
   }
 
   protected function getCustomTransactionNewValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     throw new Exception(pht('Capability not supported!'));
   }
 
   protected function transactionHasEffect(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_CREATE:
         return true;
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->getApplicationTransactionHasEffect($xaction);
       case PhabricatorTransactions::TYPE_EDGE:
         // A straight value comparison here doesn't always get the right
         // result, because newly added edges aren't fully populated. Instead,
         // compare the changes in a more granular way.
         $old = $xaction->getOldValue();
         $new = $xaction->getNewValue();
 
         $old_dst = array_keys($old);
         $new_dst = array_keys($new);
 
         // NOTE: For now, we don't consider edge reordering to be a change.
         // We have very few order-dependent edges and effectively no order
         // oriented UI. This might change in the future.
         sort($old_dst);
         sort($new_dst);
 
         if ($old_dst !== $new_dst) {
           // We've added or removed edges, so this transaction definitely
           // has an effect.
           return true;
         }
 
         // We haven't added or removed edges, but we might have changed
         // edge data.
         foreach ($old as $key => $old_value) {
           $new_value = $new[$key];
           if ($old_value['data'] !== $new_value['data']) {
             return true;
           }
         }
 
         return false;
     }
 
     $type = $xaction->getTransactionType();
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       return $xtype->getTransactionHasEffect(
         $object,
         $xaction->getOldValue(),
         $xaction->getNewValue());
     }
 
     if ($xaction->hasComment()) {
       return true;
     }
 
     return ($xaction->getOldValue() !== $xaction->getNewValue());
   }
 
   protected function shouldApplyInitialEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return false;
   }
 
   protected function applyInitialEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
     throw new PhutilMethodNotImplementedException();
   }
 
   private function applyInternalEffects(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $type = $xaction->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $xtype = clone $xtype;
       $xtype->setStorage($xaction);
       return $xtype->applyInternalEffects($object, $xaction->getNewValue());
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->applyApplicationTransactionInternalEffects($xaction);
       case PhabricatorTransactions::TYPE_CREATE:
       case PhabricatorTransactions::TYPE_SUBTYPE:
       case PhabricatorTransactions::TYPE_BUILDABLE:
       case PhabricatorTransactions::TYPE_TOKEN:
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
       case PhabricatorTransactions::TYPE_INLINESTATE:
       case PhabricatorTransactions::TYPE_EDGE:
       case PhabricatorTransactions::TYPE_SPACE:
       case PhabricatorTransactions::TYPE_COMMENT:
         return $this->applyBuiltinInternalTransaction($object, $xaction);
     }
 
     return $this->applyCustomInternalTransaction($object, $xaction);
   }
 
   private function applyExternalEffects(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $type = $xaction->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $xtype = clone $xtype;
       $xtype->setStorage($xaction);
       return $xtype->applyExternalEffects($object, $xaction->getNewValue());
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         $subeditor = id(new PhabricatorSubscriptionsEditor())
           ->setObject($object)
           ->setActor($this->requireActor());
 
         $old_map = array_fuse($xaction->getOldValue());
         $new_map = array_fuse($xaction->getNewValue());
 
         $subeditor->unsubscribe(
           array_keys(
             array_diff_key($old_map, $new_map)));
 
         $subeditor->subscribeExplicit(
           array_keys(
             array_diff_key($new_map, $old_map)));
 
         $subeditor->save();
 
         // for the rest of these edits, subscribers should include those just
         // added as well as those just removed.
         $subscribers = array_unique(array_merge(
           $this->subscribers,
           $xaction->getOldValue(),
           $xaction->getNewValue()));
         $this->subscribers = $subscribers;
         return $this->applyBuiltinExternalTransaction($object, $xaction);
 
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->applyApplicationTransactionExternalEffects($xaction);
       case PhabricatorTransactions::TYPE_CREATE:
       case PhabricatorTransactions::TYPE_SUBTYPE:
       case PhabricatorTransactions::TYPE_EDGE:
       case PhabricatorTransactions::TYPE_BUILDABLE:
       case PhabricatorTransactions::TYPE_TOKEN:
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
       case PhabricatorTransactions::TYPE_INLINESTATE:
       case PhabricatorTransactions::TYPE_SPACE:
       case PhabricatorTransactions::TYPE_COMMENT:
         return $this->applyBuiltinExternalTransaction($object, $xaction);
     }
 
     return $this->applyCustomExternalTransaction($object, $xaction);
   }
 
   protected function applyCustomInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     $type = $xaction->getTransactionType();
     throw new Exception(
       pht(
         "Transaction type '%s' is missing an internal apply implementation!",
         $type));
   }
 
   protected function applyCustomExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     $type = $xaction->getTransactionType();
     throw new Exception(
       pht(
         "Transaction type '%s' is missing an external apply implementation!",
         $type));
   }
 
   /**
    * @{class:PhabricatorTransactions} provides many built-in transactions
    * which should not require much - if any - code in specific applications.
    *
    * This method is a hook for the exceedingly-rare cases where you may need
    * to do **additional** work for built-in transactions. Developers should
    * extend this method, making sure to return the parent implementation
    * regardless of handling any transactions.
    *
    * See also @{method:applyBuiltinExternalTransaction}.
    */
   protected function applyBuiltinInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         $object->setViewPolicy($xaction->getNewValue());
         break;
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         $object->setEditPolicy($xaction->getNewValue());
         break;
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
         $object->setJoinPolicy($xaction->getNewValue());
         break;
       case PhabricatorTransactions::TYPE_SPACE:
         $object->setSpacePHID($xaction->getNewValue());
         break;
       case PhabricatorTransactions::TYPE_SUBTYPE:
         $object->setEditEngineSubtype($xaction->getNewValue());
         break;
     }
   }
 
   /**
    * See @{method::applyBuiltinInternalTransaction}.
    */
   protected function applyBuiltinExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_EDGE:
         if ($this->getIsInverseEdgeEditor()) {
           // If we're writing an inverse edge transaction, don't actually
           // do anything. The initiating editor on the other side of the
           // transaction will take care of the edge writes.
           break;
         }
 
         $old = $xaction->getOldValue();
         $new = $xaction->getNewValue();
         $src = $object->getPHID();
         $const = $xaction->getMetadataValue('edge:type');
 
         $type = PhabricatorEdgeType::getByConstant($const);
         if ($type->shouldWriteInverseTransactions()) {
           $this->applyInverseEdgeTransactions(
             $object,
             $xaction,
             $type->getInverseEdgeConstant());
         }
 
         foreach ($new as $dst_phid => $edge) {
           $new[$dst_phid]['src'] = $src;
         }
 
         $editor = new PhabricatorEdgeEditor();
 
         foreach ($old as $dst_phid => $edge) {
           if (!empty($new[$dst_phid])) {
             if ($old[$dst_phid]['data'] === $new[$dst_phid]['data']) {
               continue;
             }
           }
           $editor->removeEdge($src, $const, $dst_phid);
         }
 
         foreach ($new as $dst_phid => $edge) {
           if (!empty($old[$dst_phid])) {
             if ($old[$dst_phid]['data'] === $new[$dst_phid]['data']) {
               continue;
             }
           }
 
           $data = array(
             'data' => $edge['data'],
           );
 
           $editor->addEdge($src, $const, $dst_phid, $data);
         }
 
         $editor->save();
 
         $this->updateWorkboardColumns($object, $const, $old, $new);
         break;
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_SPACE:
         $this->scrambleFileSecrets($object);
         break;
     }
   }
 
   /**
    * Fill in a transaction's common values, like author and content source.
    */
   protected function populateTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $actor = $this->getActor();
 
     // TODO: This needs to be more sophisticated once we have meta-policies.
     $xaction->setViewPolicy(PhabricatorPolicies::POLICY_PUBLIC);
 
     if ($actor->isOmnipotent()) {
       $xaction->setEditPolicy(PhabricatorPolicies::POLICY_NOONE);
     } else {
       $xaction->setEditPolicy($this->getActingAsPHID());
     }
 
     // If the transaction already has an explicit author PHID, allow it to
     // stand. This is used by applications like Owners that hook into the
     // post-apply change pipeline.
     if (!$xaction->getAuthorPHID()) {
       $xaction->setAuthorPHID($this->getActingAsPHID());
     }
 
     $xaction->setContentSource($this->getContentSource());
     $xaction->attachViewer($actor);
     $xaction->attachObject($object);
 
     if ($object->getPHID()) {
       $xaction->setObjectPHID($object->getPHID());
     }
 
     if ($this->getIsSilent()) {
       $xaction->setIsSilentTransaction(true);
     }
 
     return $xaction;
   }
 
   protected function didApplyInternalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $xactions;
   }
 
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $xactions;
   }
 
   public function setContentSource(PhabricatorContentSource $content_source) {
     $this->contentSource = $content_source;
     return $this;
   }
 
   public function setContentSourceFromRequest(AphrontRequest $request) {
     return $this->setContentSource(
       PhabricatorContentSource::newFromRequest($request));
   }
 
   public function getContentSource() {
     return $this->contentSource;
   }
 
   final public function applyTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $this->object = $object;
     $this->xactions = $xactions;
     $this->isNewObject = ($object->getPHID() === null);
 
     $this->validateEditParameters($object, $xactions);
 
     $actor = $this->requireActor();
 
     // NOTE: Some transaction expansion requires that the edited object be
     // attached.
     foreach ($xactions as $xaction) {
       $xaction->attachObject($object);
       $xaction->attachViewer($actor);
     }
 
     $xactions = $this->expandTransactions($object, $xactions);
     $xactions = $this->expandSupportTransactions($object, $xactions);
     $xactions = $this->combineTransactions($xactions);
 
     foreach ($xactions as $xaction) {
       $xaction = $this->populateTransaction($object, $xaction);
     }
 
     $is_preview = $this->getIsPreview();
     $read_locking = false;
     $transaction_open = false;
 
     if (!$is_preview) {
       $errors = array();
       $type_map = mgroup($xactions, 'getTransactionType');
       foreach ($this->getTransactionTypes() as $type) {
         $type_xactions = idx($type_map, $type, array());
         $errors[] = $this->validateTransaction($object, $type, $type_xactions);
       }
 
       $errors[] = $this->validateAllTransactions($object, $xactions);
       $errors = array_mergev($errors);
 
       $continue_on_missing = $this->getContinueOnMissingFields();
       foreach ($errors as $key => $error) {
         if ($continue_on_missing && $error->getIsMissingFieldError()) {
           unset($errors[$key]);
         }
       }
 
       if ($errors) {
         throw new PhabricatorApplicationTransactionValidationException($errors);
       }
 
       $this->willApplyTransactions($object, $xactions);
 
       if ($object->getID()) {
         $this->buildOldRecipientLists($object, $xactions);
 
         foreach ($xactions as $xaction) {
 
           // If any of the transactions require a read lock, hold one and
           // reload the object. We need to do this fairly early so that the
           // call to `adjustTransactionValues()` (which populates old values)
           // is based on the synchronized state of the object, which may differ
           // from the state when it was originally loaded.
 
           if ($this->shouldReadLock($object, $xaction)) {
             $object->openTransaction();
             $object->beginReadLocking();
             $transaction_open = true;
             $read_locking = true;
             $object->reload();
             break;
           }
         }
       }
 
       if ($this->shouldApplyInitialEffects($object, $xactions)) {
         if (!$transaction_open) {
           $object->openTransaction();
           $transaction_open = true;
         }
       }
     }
 
     if ($this->shouldApplyInitialEffects($object, $xactions)) {
       $this->applyInitialEffects($object, $xactions);
     }
 
     foreach ($xactions as $xaction) {
       $this->adjustTransactionValues($object, $xaction);
     }
 
     try {
       $xactions = $this->filterTransactions($object, $xactions);
     } catch (Exception $ex) {
       if ($read_locking) {
         $object->endReadLocking();
       }
       if ($transaction_open) {
         $object->killTransaction();
       }
       throw $ex;
     }
 
     // TODO: Once everything is on EditEngine, just use getIsNewObject() to
     // figure this out instead.
     $mark_as_create = false;
     $create_type = PhabricatorTransactions::TYPE_CREATE;
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() == $create_type) {
         $mark_as_create = true;
       }
     }
 
     if ($mark_as_create) {
       foreach ($xactions as $xaction) {
         $xaction->setIsCreateTransaction(true);
       }
     }
 
     // Now that we've merged, filtered, and combined transactions, check for
     // required capabilities.
     foreach ($xactions as $xaction) {
       $this->requireCapabilities($object, $xaction);
     }
 
     $xactions = $this->sortTransactions($xactions);
     $file_phids = $this->extractFilePHIDs($object, $xactions);
 
     if ($is_preview) {
       $this->loadHandles($xactions);
       return $xactions;
     }
 
     $comment_editor = id(new PhabricatorApplicationTransactionCommentEditor())
       ->setActor($actor)
       ->setActingAsPHID($this->getActingAsPHID())
       ->setContentSource($this->getContentSource());
 
     if (!$transaction_open) {
       $object->openTransaction();
     }
 
     try {
       foreach ($xactions as $xaction) {
         $this->applyInternalEffects($object, $xaction);
       }
 
       $xactions = $this->didApplyInternalEffects($object, $xactions);
 
       try {
         $object->save();
       } catch (AphrontDuplicateKeyQueryException $ex) {
         // This callback has an opportunity to throw a better exception,
         // so execution may end here.
         $this->didCatchDuplicateKeyException($object, $xactions, $ex);
 
         throw $ex;
       }
 
       foreach ($xactions as $xaction) {
         $xaction->setObjectPHID($object->getPHID());
         if ($xaction->getComment()) {
           $xaction->setPHID($xaction->generatePHID());
           $comment_editor->applyEdit($xaction, $xaction->getComment());
         } else {
 
           // TODO: This is a transitional hack to let us migrate edge
           // transactions to a more efficient storage format. For now, we're
           // going to write a new slim format to the database but keep the old
           // bulky format on the objects so we don't have to upgrade all the
           // edit logic to the new format yet. See T13051.
 
           $edge_type = PhabricatorTransactions::TYPE_EDGE;
           if ($xaction->getTransactionType() == $edge_type) {
             $bulky_old = $xaction->getOldValue();
             $bulky_new = $xaction->getNewValue();
 
             $record = PhabricatorEdgeChangeRecord::newFromTransaction($xaction);
             $slim_old = $record->getModernOldEdgeTransactionData();
             $slim_new = $record->getModernNewEdgeTransactionData();
 
             $xaction->setOldValue($slim_old);
             $xaction->setNewValue($slim_new);
             $xaction->save();
 
             $xaction->setOldValue($bulky_old);
             $xaction->setNewValue($bulky_new);
           } else {
             $xaction->save();
           }
         }
       }
 
       if ($file_phids) {
         $this->attachFiles($object, $file_phids);
       }
 
       foreach ($xactions as $xaction) {
         $this->applyExternalEffects($object, $xaction);
       }
 
       $xactions = $this->applyFinalEffects($object, $xactions);
       if ($read_locking) {
         $object->endReadLocking();
         $read_locking = false;
       }
 
       $object->saveTransaction();
     } catch (Exception $ex) {
       $object->killTransaction();
       throw $ex;
     }
 
     // If we need to perform cache engine updates, execute them now.
     id(new PhabricatorCacheEngine())
       ->updateObject($object);
 
     // Now that we've completely applied the core transaction set, try to apply
     // Herald rules. Herald rules are allowed to either take direct actions on
     // the database (like writing flags), or take indirect actions (like saving
     // some targets for CC when we generate mail a little later), or return
     // transactions which we'll apply normally using another Editor.
 
     // First, check if *this* is a sub-editor which is itself applying Herald
     // rules: if it is, stop working and return so we don't descend into
     // madness.
 
     // Otherwise, we're not a Herald editor, so process Herald rules (possibly
     // using a Herald editor to apply resulting transactions) and then send out
     // mail, notifications, and feed updates about everything.
 
     if ($this->getIsHeraldEditor()) {
       // We are the Herald editor, so stop work here and return the updated
       // transactions.
       return $xactions;
     } else if ($this->shouldApplyHeraldRules($object, $xactions)) {
       // We are not the Herald editor, so try to apply Herald rules.
       $herald_xactions = $this->applyHeraldRules($object, $xactions);
 
       if ($herald_xactions) {
         $xscript_id = $this->getHeraldTranscript()->getID();
         foreach ($herald_xactions as $herald_xaction) {
           // Don't set a transcript ID if this is a transaction from another
           // application or source, like Owners.
           if ($herald_xaction->getAuthorPHID()) {
             continue;
           }
 
           $herald_xaction->setMetadataValue('herald:transcriptID', $xscript_id);
         }
 
         // NOTE: We're acting as the omnipotent user because rules deal with
         // their own policy issues. We use a synthetic author PHID (the
         // Herald application) as the author of record, so that transactions
         // will render in a reasonable way ("Herald assigned this task ...").
         $herald_actor = PhabricatorUser::getOmnipotentUser();
         $herald_phid = id(new PhabricatorHeraldApplication())->getPHID();
 
         // TODO: It would be nice to give transactions a more specific source
         // which points at the rule which generated them. You can figure this
         // out from transcripts, but it would be cleaner if you didn't have to.
 
         $herald_source = PhabricatorContentSource::newForSource(
           PhabricatorHeraldContentSource::SOURCECONST);
 
         $herald_editor = newv(get_class($this), array())
           ->setContinueOnNoEffect(true)
           ->setContinueOnMissingFields(true)
           ->setParentMessageID($this->getParentMessageID())
           ->setIsHeraldEditor(true)
           ->setActor($herald_actor)
           ->setActingAsPHID($herald_phid)
           ->setContentSource($herald_source);
 
         $herald_xactions = $herald_editor->applyTransactions(
           $object,
           $herald_xactions);
 
         // Merge the new transactions into the transaction list: we want to
         // send email and publish feed stories about them, too.
         $xactions = array_merge($xactions, $herald_xactions);
       }
 
       // If Herald did not generate transactions, we may still need to handle
       // "Send an Email" rules.
       $adapter = $this->getHeraldAdapter();
       $this->heraldEmailPHIDs = $adapter->getEmailPHIDs();
       $this->heraldForcedEmailPHIDs = $adapter->getForcedEmailPHIDs();
     }
 
     $xactions = $this->didApplyTransactions($object, $xactions);
 
     if ($object instanceof PhabricatorCustomFieldInterface) {
       // Maybe this makes more sense to move into the search index itself? For
       // now I'm putting it here since I think we might end up with things that
       // need it to be up to date once the next page loads, but if we don't go
       // there we could move it into search once search moves to the daemons.
 
       // It now happens in the search indexer as well, but the search indexer is
       // always daemonized, so the logic above still potentially holds. We could
       // possibly get rid of this. The major motivation for putting it in the
       // indexer was to enable reindexing to work.
 
       $fields = PhabricatorCustomField::getObjectFields(
         $object,
         PhabricatorCustomField::ROLE_APPLICATIONSEARCH);
       $fields->readFieldsFromStorage($object);
       $fields->rebuildIndexes($object);
     }
 
     $herald_xscript = $this->getHeraldTranscript();
     if ($herald_xscript) {
       $herald_header = $herald_xscript->getXHeraldRulesHeader();
       $herald_header = HeraldTranscript::saveXHeraldRulesHeader(
         $object->getPHID(),
         $herald_header);
     } else {
       $herald_header = HeraldTranscript::loadXHeraldRulesHeader(
         $object->getPHID());
     }
     $this->heraldHeader = $herald_header;
 
     // We're going to compute some of the data we'll use to publish these
     // transactions here, before queueing a worker.
     //
     // Primarily, this is more correct: we want to publish the object as it
     // exists right now. The worker may not execute for some time, and we want
     // to use the current To/CC list, not respect any changes which may occur
     // between now and when the worker executes.
     //
     // As a secondary benefit, this tends to reduce the amount of state that
     // Editors need to pass into workers.
     $object = $this->willPublish($object, $xactions);
 
     if (!$this->getIsSilent()) {
       if ($this->shouldSendMail($object, $xactions)) {
         $this->mailShouldSend = true;
         $this->mailToPHIDs = $this->getMailTo($object);
         $this->mailCCPHIDs = $this->getMailCC($object);
+        $this->mailUnexpandablePHIDs = $this->newMailUnexpandablePHIDs($object);
 
         // Add any recipients who were previously on the notification list
         // but were removed by this change.
         $this->applyOldRecipientLists();
 
         $mail_xactions = $this->getTransactionsForMail($object, $xactions);
         $stamps = $this->newMailStamps($object, $xactions);
         foreach ($stamps as $stamp) {
           $this->mailStamps[] = $stamp->toDictionary();
         }
       }
 
       if ($this->shouldPublishFeedStory($object, $xactions)) {
         $this->feedShouldPublish = true;
         $this->feedRelatedPHIDs = $this->getFeedRelatedPHIDs(
           $object,
           $xactions);
         $this->feedNotifyPHIDs = $this->getFeedNotifyPHIDs(
           $object,
           $xactions);
       }
     }
 
     PhabricatorWorker::scheduleTask(
       'PhabricatorApplicationTransactionPublishWorker',
       array(
         'objectPHID' => $object->getPHID(),
         'actorPHID' => $this->getActingAsPHID(),
         'xactionPHIDs' => mpull($xactions, 'getPHID'),
         'state' => $this->getWorkerState(),
       ),
       array(
         'objectPHID' => $object->getPHID(),
         'priority' => PhabricatorWorker::PRIORITY_ALERTS,
       ));
 
     $this->flushTransactionQueue($object);
 
     return $xactions;
   }
 
   protected function didCatchDuplicateKeyException(
     PhabricatorLiskDAO $object,
     array $xactions,
     Exception $ex) {
     return;
   }
 
   public function publishTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $this->object = $object;
     $this->xactions = $xactions;
 
     // Hook for edges or other properties that may need (re-)loading
     $object = $this->willPublish($object, $xactions);
 
     // The object might have changed, so reassign it.
     $this->object = $object;
 
     $messages = array();
     if ($this->mailShouldSend) {
       $messages = $this->buildMail($object, $xactions);
     }
 
     if ($this->supportsSearch()) {
       PhabricatorSearchWorker::queueDocumentForIndexing(
         $object->getPHID(),
         array(
           'transactionPHIDs' => mpull($xactions, 'getPHID'),
         ));
     }
 
     if ($this->feedShouldPublish) {
       $mailed = array();
       foreach ($messages as $mail) {
         foreach ($mail->buildRecipientList() as $phid) {
           $mailed[$phid] = $phid;
         }
       }
 
       $this->publishFeedStory($object, $xactions, $mailed);
     }
 
     // NOTE: This actually sends the mail. We do this last to reduce the chance
     // that we send some mail, hit an exception, then send the mail again when
     // retrying.
     foreach ($messages as $mail) {
       $mail->save();
     }
 
     return $xactions;
   }
 
   protected function didApplyTransactions($object, array $xactions) {
     // Hook for subclasses.
     return $xactions;
   }
 
 
   /**
    * Determine if the editor should hold a read lock on the object while
    * applying a transaction.
    *
    * If the editor does not hold a lock, two editors may read an object at the
    * same time, then apply their changes without any synchronization. For most
    * transactions, this does not matter much. However, it is important for some
    * transactions. For example, if an object has a transaction count on it, both
    * editors may read the object with `count = 23`, then independently update it
    * and save the object with `count = 24` twice. This will produce the wrong
    * state: the object really has 25 transactions, but the count is only 24.
    *
    * Generally, transactions fall into one of four buckets:
    *
    *   - Append operations: Actions like adding a comment to an object purely
    *     add information to its state, and do not depend on the current object
    *     state in any way. These transactions never need to hold locks.
    *   - Overwrite operations: Actions like changing the title or description
    *     of an object replace the current value with a new value, so the end
    *     state is consistent without a lock. We currently do not lock these
    *     transactions, although we may in the future.
    *   - Edge operations: Edge and subscription operations have internal
    *     synchronization which limits the damage race conditions can cause.
    *     We do not currently lock these transactions, although we may in the
    *     future.
    *   - Update operations: Actions like incrementing a count on an object.
    *     These operations generally should use locks, unless it is not
    *     important that the state remain consistent in the presence of races.
    *
    * @param   PhabricatorLiskDAO  Object being updated.
    * @param   PhabricatorApplicationTransaction Transaction being applied.
    * @return  bool                True to synchronize the edit with a lock.
    */
   protected function shouldReadLock(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     return false;
   }
 
   private function loadHandles(array $xactions) {
     $phids = array();
     foreach ($xactions as $key => $xaction) {
       $phids[$key] = $xaction->getRequiredHandlePHIDs();
     }
     $handles = array();
     $merged = array_mergev($phids);
     if ($merged) {
       $handles = id(new PhabricatorHandleQuery())
         ->setViewer($this->requireActor())
         ->withPHIDs($merged)
         ->execute();
     }
     foreach ($xactions as $key => $xaction) {
       $xaction->setHandles(array_select_keys($handles, $phids[$key]));
     }
   }
 
   private function loadSubscribers(PhabricatorLiskDAO $object) {
     if ($object->getPHID() &&
         ($object instanceof PhabricatorSubscribableInterface)) {
       $subs = PhabricatorSubscribersQuery::loadSubscribersForPHID(
         $object->getPHID());
       $this->subscribers = array_fuse($subs);
     } else {
       $this->subscribers = array();
     }
   }
 
   private function validateEditParameters(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if (!$this->getContentSource()) {
       throw new PhutilInvalidStateException('setContentSource');
     }
 
     // Do a bunch of sanity checks that the incoming transactions are fresh.
     // They should be unsaved and have only "transactionType" and "newValue"
     // set.
 
     $types = array_fill_keys($this->getTransactionTypes(), true);
 
     assert_instances_of($xactions, 'PhabricatorApplicationTransaction');
     foreach ($xactions as $xaction) {
       if ($xaction->getPHID() || $xaction->getID()) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht('You can not apply transactions which already have IDs/PHIDs!'));
       }
 
       if ($xaction->getObjectPHID()) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'You can not apply transactions which already have %s!',
             'objectPHIDs'));
       }
 
       if ($xaction->getCommentPHID()) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'You can not apply transactions which already have %s!',
             'commentPHIDs'));
       }
 
       if ($xaction->getCommentVersion() !== 0) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'You can not apply transactions which already have '.
             'commentVersions!'));
       }
 
       $expect_value = !$xaction->shouldGenerateOldValue();
       $has_value = $xaction->hasOldValue();
 
       if ($expect_value && !$has_value) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'This transaction is supposed to have an %s set, but it does not!',
             'oldValue'));
       }
 
       if ($has_value && !$expect_value) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'This transaction should generate its %s automatically, '.
             'but has already had one set!',
             'oldValue'));
       }
 
       $type = $xaction->getTransactionType();
       if (empty($types[$type])) {
         throw new PhabricatorApplicationTransactionStructureException(
           $xaction,
           pht(
             'Transaction has type "%s", but that transaction type is not '.
             'supported by this editor (%s).',
             $type,
             get_class($this)));
       }
     }
   }
 
   protected function requireCapabilities(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     if ($this->getIsNewObject()) {
       return;
     }
 
     $actor = $this->requireActor();
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         PhabricatorPolicyFilter::requireCapability(
           $actor,
           $object,
           PhabricatorPolicyCapability::CAN_VIEW);
         break;
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
       case PhabricatorTransactions::TYPE_JOIN_POLICY:
       case PhabricatorTransactions::TYPE_SPACE:
         PhabricatorPolicyFilter::requireCapability(
           $actor,
           $object,
           PhabricatorPolicyCapability::CAN_EDIT);
         break;
     }
   }
 
   private function buildSubscribeTransaction(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $changes) {
 
     if (!($object instanceof PhabricatorSubscribableInterface)) {
       return null;
     }
 
     if ($this->shouldEnableMentions($object, $xactions)) {
       // Identify newly mentioned users. We ignore users who were previously
       // mentioned so that we don't re-subscribe users after an edit of text
       // which mentions them.
       $old_texts = mpull($changes, 'getOldValue');
       $new_texts = mpull($changes, 'getNewValue');
 
       $old_phids = PhabricatorMarkupEngine::extractPHIDsFromMentions(
         $this->getActor(),
         $old_texts);
 
       $new_phids = PhabricatorMarkupEngine::extractPHIDsFromMentions(
         $this->getActor(),
         $new_texts);
 
       $phids = array_diff($new_phids, $old_phids);
     } else {
       $phids = array();
     }
 
     $this->mentionedPHIDs = $phids;
 
     if ($object->getPHID()) {
       // Don't try to subscribe already-subscribed mentions: we want to generate
       // a dialog about an action having no effect if the user explicitly adds
       // existing CCs, but not if they merely mention existing subscribers.
       $phids = array_diff($phids, $this->subscribers);
     }
 
     if ($phids) {
       $users = id(new PhabricatorPeopleQuery())
         ->setViewer($this->getActor())
         ->withPHIDs($phids)
         ->execute();
       $users = mpull($users, null, 'getPHID');
 
       foreach ($phids as $key => $phid) {
         // Do not subscribe mentioned users
         // who do not have VIEW Permissions
         if ($object instanceof PhabricatorPolicyInterface
           && !PhabricatorPolicyFilter::hasCapability(
           $users[$phid],
           $object,
           PhabricatorPolicyCapability::CAN_VIEW)
         ) {
           unset($phids[$key]);
         } else {
           if ($object->isAutomaticallySubscribed($phid)) {
             unset($phids[$key]);
           }
         }
       }
       $phids = array_values($phids);
     }
     // No else here to properly return null should we unset all subscriber
     if (!$phids) {
       return null;
     }
 
     $xaction = newv(get_class(head($xactions)), array());
     $xaction->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS);
     $xaction->setNewValue(array('+' => $phids));
 
     return $xaction;
   }
 
   protected function mergeTransactions(
     PhabricatorApplicationTransaction $u,
     PhabricatorApplicationTransaction $v) {
 
     $type = $u->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $object = $this->object;
       return $xtype->mergeTransactions($object, $u, $v);
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_SUBSCRIBERS:
         return $this->mergePHIDOrEdgeTransactions($u, $v);
       case PhabricatorTransactions::TYPE_EDGE:
         $u_type = $u->getMetadataValue('edge:type');
         $v_type = $v->getMetadataValue('edge:type');
         if ($u_type == $v_type) {
           return $this->mergePHIDOrEdgeTransactions($u, $v);
         }
         return null;
     }
 
     // By default, do not merge the transactions.
     return null;
   }
 
   /**
    * Optionally expand transactions which imply other effects. For example,
    * resigning from a revision in Differential implies removing yourself as
    * a reviewer.
    */
   protected function expandTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $results = array();
     foreach ($xactions as $xaction) {
       foreach ($this->expandTransaction($object, $xaction) as $expanded) {
         $results[] = $expanded;
       }
     }
 
     return $results;
   }
 
   protected function expandTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     return array($xaction);
   }
 
 
   public function getExpandedSupportTransactions(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $xactions = array($xaction);
     $xactions = $this->expandSupportTransactions(
       $object,
       $xactions);
 
     if (count($xactions) == 1) {
       return array();
     }
 
     foreach ($xactions as $index => $cxaction) {
       if ($cxaction === $xaction) {
         unset($xactions[$index]);
         break;
       }
     }
 
     return $xactions;
   }
 
   private function expandSupportTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
     $this->loadSubscribers($object);
 
     $xactions = $this->applyImplicitCC($object, $xactions);
 
     $changes = $this->getRemarkupChanges($xactions);
 
     $subscribe_xaction = $this->buildSubscribeTransaction(
       $object,
       $xactions,
       $changes);
     if ($subscribe_xaction) {
       $xactions[] = $subscribe_xaction;
     }
 
     // TODO: For now, this is just a placeholder.
     $engine = PhabricatorMarkupEngine::getEngine('extract');
     $engine->setConfig('viewer', $this->requireActor());
 
     $block_xactions = $this->expandRemarkupBlockTransactions(
       $object,
       $xactions,
       $changes,
       $engine);
 
     foreach ($block_xactions as $xaction) {
       $xactions[] = $xaction;
     }
 
     return $xactions;
   }
 
   private function getRemarkupChanges(array $xactions) {
     $changes = array();
 
     foreach ($xactions as $key => $xaction) {
       foreach ($this->getRemarkupChangesFromTransaction($xaction) as $change) {
         $changes[] = $change;
       }
     }
 
     return $changes;
   }
 
   private function getRemarkupChangesFromTransaction(
     PhabricatorApplicationTransaction $transaction) {
     return $transaction->getRemarkupChanges();
   }
 
   private function expandRemarkupBlockTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $changes,
     PhutilMarkupEngine $engine) {
 
     $block_xactions = $this->expandCustomRemarkupBlockTransactions(
       $object,
       $xactions,
       $changes,
       $engine);
 
     $mentioned_phids = array();
     if ($this->shouldEnableMentions($object, $xactions)) {
       foreach ($changes as $change) {
         // Here, we don't care about processing only new mentions after an edit
         // because there is no way for an object to ever "unmention" itself on
         // another object, so we can ignore the old value.
         $engine->markupText($change->getNewValue());
 
         $mentioned_phids += $engine->getTextMetadata(
           PhabricatorObjectRemarkupRule::KEY_MENTIONED_OBJECTS,
           array());
       }
     }
 
     if (!$mentioned_phids) {
       return $block_xactions;
     }
 
     $mentioned_objects = id(new PhabricatorObjectQuery())
       ->setViewer($this->getActor())
       ->withPHIDs($mentioned_phids)
       ->execute();
 
     $mentionable_phids = array();
     if ($this->shouldEnableMentions($object, $xactions)) {
       foreach ($mentioned_objects as $mentioned_object) {
         if ($mentioned_object instanceof PhabricatorMentionableInterface) {
           $mentioned_phid = $mentioned_object->getPHID();
           if (idx($this->getUnmentionablePHIDMap(), $mentioned_phid)) {
             continue;
           }
           // don't let objects mention themselves
           if ($object->getPHID() && $mentioned_phid == $object->getPHID()) {
             continue;
           }
           $mentionable_phids[$mentioned_phid] = $mentioned_phid;
         }
       }
     }
 
     if ($mentionable_phids) {
       $edge_type = PhabricatorObjectMentionsObjectEdgeType::EDGECONST;
       $block_xactions[] = newv(get_class(head($xactions)), array())
         ->setIgnoreOnNoEffect(true)
         ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
         ->setMetadataValue('edge:type', $edge_type)
         ->setNewValue(array('+' => $mentionable_phids));
     }
 
     return $block_xactions;
   }
 
   protected function expandCustomRemarkupBlockTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $changes,
     PhutilMarkupEngine $engine) {
     return array();
   }
 
 
   /**
    * Attempt to combine similar transactions into a smaller number of total
    * transactions. For example, two transactions which edit the title of an
    * object can be merged into a single edit.
    */
   private function combineTransactions(array $xactions) {
     $stray_comments = array();
 
     $result = array();
     $types = array();
     foreach ($xactions as $key => $xaction) {
       $type = $xaction->getTransactionType();
       if (isset($types[$type])) {
         foreach ($types[$type] as $other_key) {
           $other_xaction = $result[$other_key];
 
           // Don't merge transactions with different authors. For example,
           // don't merge Herald transactions and owners transactions.
           if ($other_xaction->getAuthorPHID() != $xaction->getAuthorPHID()) {
             continue;
           }
 
           $merged = $this->mergeTransactions($result[$other_key], $xaction);
           if ($merged) {
             $result[$other_key] = $merged;
 
             if ($xaction->getComment() &&
                 ($xaction->getComment() !== $merged->getComment())) {
               $stray_comments[] = $xaction->getComment();
             }
 
             if ($result[$other_key]->getComment() &&
                 ($result[$other_key]->getComment() !== $merged->getComment())) {
               $stray_comments[] = $result[$other_key]->getComment();
             }
 
             // Move on to the next transaction.
             continue 2;
           }
         }
       }
       $result[$key] = $xaction;
       $types[$type][] = $key;
     }
 
     // If we merged any comments away, restore them.
     foreach ($stray_comments as $comment) {
       $xaction = newv(get_class(head($result)), array());
       $xaction->setTransactionType(PhabricatorTransactions::TYPE_COMMENT);
       $xaction->setComment($comment);
       $result[] = $xaction;
     }
 
     return array_values($result);
   }
 
   public function mergePHIDOrEdgeTransactions(
     PhabricatorApplicationTransaction $u,
     PhabricatorApplicationTransaction $v) {
 
     $result = $u->getNewValue();
     foreach ($v->getNewValue() as $key => $value) {
       if ($u->getTransactionType() == PhabricatorTransactions::TYPE_EDGE) {
         if (empty($result[$key])) {
           $result[$key] = $value;
         } else {
           // We're merging two lists of edge adds, sets, or removes. Merge
           // them by merging individual PHIDs within them.
           $merged = $result[$key];
 
           foreach ($value as $dst => $v_spec) {
             if (empty($merged[$dst])) {
               $merged[$dst] = $v_spec;
             } else {
               // Two transactions are trying to perform the same operation on
               // the same edge. Normalize the edge data and then merge it. This
               // allows transactions to specify how data merges execute in a
               // precise way.
 
               $u_spec = $merged[$dst];
 
               if (!is_array($u_spec)) {
                 $u_spec = array('dst' => $u_spec);
               }
               if (!is_array($v_spec)) {
                 $v_spec = array('dst' => $v_spec);
               }
 
               $ux_data = idx($u_spec, 'data', array());
               $vx_data = idx($v_spec, 'data', array());
 
               $merged_data = $this->mergeEdgeData(
                 $u->getMetadataValue('edge:type'),
                 $ux_data,
                 $vx_data);
 
               $u_spec['data'] = $merged_data;
               $merged[$dst] = $u_spec;
             }
           }
 
           $result[$key] = $merged;
         }
       } else {
         $result[$key] = array_merge($value, idx($result, $key, array()));
       }
     }
     $u->setNewValue($result);
 
     // When combining an "ignore" transaction with a normal transaction, make
     // sure we don't propagate the "ignore" flag.
     if (!$v->getIgnoreOnNoEffect()) {
       $u->setIgnoreOnNoEffect(false);
     }
 
     return $u;
   }
 
   protected function mergeEdgeData($type, array $u, array $v) {
     return $v + $u;
   }
 
   protected function getPHIDTransactionNewValue(
     PhabricatorApplicationTransaction $xaction,
     $old = null) {
 
     if ($old !== null) {
       $old = array_fuse($old);
     } else {
       $old = array_fuse($xaction->getOldValue());
     }
 
     return $this->getPHIDList($old, $xaction->getNewValue());
   }
 
   public function getPHIDList(array $old, array $new) {
     $new_add = idx($new, '+', array());
     unset($new['+']);
     $new_rem = idx($new, '-', array());
     unset($new['-']);
     $new_set = idx($new, '=', null);
     if ($new_set !== null) {
       $new_set = array_fuse($new_set);
     }
     unset($new['=']);
 
     if ($new) {
       throw new Exception(
         pht(
           "Invalid '%s' value for PHID transaction. Value should contain only ".
           "keys '%s' (add PHIDs), '%s' (remove PHIDs) and '%s' (set PHIDS).",
           'new',
           '+',
           '-',
           '='));
     }
 
     $result = array();
 
     foreach ($old as $phid) {
       if ($new_set !== null && empty($new_set[$phid])) {
         continue;
       }
       $result[$phid] = $phid;
     }
 
     if ($new_set !== null) {
       foreach ($new_set as $phid) {
         $result[$phid] = $phid;
       }
     }
 
     foreach ($new_add as $phid) {
       $result[$phid] = $phid;
     }
 
     foreach ($new_rem as $phid) {
       unset($result[$phid]);
     }
 
     return array_values($result);
   }
 
   protected function getEdgeTransactionNewValue(
     PhabricatorApplicationTransaction $xaction) {
 
     $new = $xaction->getNewValue();
     $new_add = idx($new, '+', array());
     unset($new['+']);
     $new_rem = idx($new, '-', array());
     unset($new['-']);
     $new_set = idx($new, '=', null);
     unset($new['=']);
 
     if ($new) {
       throw new Exception(
         pht(
           "Invalid '%s' value for Edge transaction. Value should contain only ".
           "keys '%s' (add edges), '%s' (remove edges) and '%s' (set edges).",
           'new',
           '+',
           '-',
           '='));
     }
 
     $old = $xaction->getOldValue();
 
     $lists = array($new_set, $new_add, $new_rem);
     foreach ($lists as $list) {
       $this->checkEdgeList($list, $xaction->getMetadataValue('edge:type'));
     }
 
     $result = array();
     foreach ($old as $dst_phid => $edge) {
       if ($new_set !== null && empty($new_set[$dst_phid])) {
         continue;
       }
       $result[$dst_phid] = $this->normalizeEdgeTransactionValue(
         $xaction,
         $edge,
         $dst_phid);
     }
 
     if ($new_set !== null) {
       foreach ($new_set as $dst_phid => $edge) {
         $result[$dst_phid] = $this->normalizeEdgeTransactionValue(
           $xaction,
           $edge,
           $dst_phid);
       }
     }
 
     foreach ($new_add as $dst_phid => $edge) {
       $result[$dst_phid] = $this->normalizeEdgeTransactionValue(
         $xaction,
         $edge,
         $dst_phid);
     }
 
     foreach ($new_rem as $dst_phid => $edge) {
       unset($result[$dst_phid]);
     }
 
     return $result;
   }
 
   private function checkEdgeList($list, $edge_type) {
     if (!$list) {
       return;
     }
     foreach ($list as $key => $item) {
       if (phid_get_type($key) === PhabricatorPHIDConstants::PHID_TYPE_UNKNOWN) {
         throw new Exception(
           pht(
             'Edge transactions must have destination PHIDs as in edge '.
             'lists (found key "%s" on transaction of type "%s").',
             $key,
             $edge_type));
       }
       if (!is_array($item) && $item !== $key) {
         throw new Exception(
           pht(
             'Edge transactions must have PHIDs or edge specs as values '.
             '(found value "%s" on transaction of type "%s").',
             $item,
             $edge_type));
       }
     }
   }
 
   private function normalizeEdgeTransactionValue(
     PhabricatorApplicationTransaction $xaction,
     $edge,
     $dst_phid) {
 
     if (!is_array($edge)) {
       if ($edge != $dst_phid) {
         throw new Exception(
           pht(
             'Transaction edge data must either be the edge PHID or an edge '.
             'specification dictionary.'));
       }
       $edge = array();
     } else {
       foreach ($edge as $key => $value) {
         switch ($key) {
           case 'src':
           case 'dst':
           case 'type':
           case 'data':
           case 'dateCreated':
           case 'dateModified':
           case 'seq':
           case 'dataID':
             break;
           default:
             throw new Exception(
               pht(
                 'Transaction edge specification contains unexpected key "%s".',
                 $key));
         }
       }
     }
 
     $edge['dst'] = $dst_phid;
 
     $edge_type = $xaction->getMetadataValue('edge:type');
     if (empty($edge['type'])) {
       $edge['type'] = $edge_type;
     } else {
       if ($edge['type'] != $edge_type) {
         $this_type = $edge['type'];
         throw new Exception(
           pht(
             "Edge transaction includes edge of type '%s', but ".
             "transaction is of type '%s'. Each edge transaction ".
             "must alter edges of only one type.",
             $this_type,
             $edge_type));
       }
     }
 
     if (!isset($edge['data'])) {
       $edge['data'] = array();
     }
 
     return $edge;
   }
 
   protected function sortTransactions(array $xactions) {
     $head = array();
     $tail = array();
 
     // Move bare comments to the end, so the actions precede them.
     foreach ($xactions as $xaction) {
       $type = $xaction->getTransactionType();
       if ($type == PhabricatorTransactions::TYPE_COMMENT) {
         $tail[] = $xaction;
       } else {
         $head[] = $xaction;
       }
     }
 
     return array_values(array_merge($head, $tail));
   }
 
 
   protected function filterTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $type_comment = PhabricatorTransactions::TYPE_COMMENT;
 
     $no_effect = array();
     $has_comment = false;
     $any_effect = false;
     foreach ($xactions as $key => $xaction) {
       if ($this->transactionHasEffect($object, $xaction)) {
         if ($xaction->getTransactionType() != $type_comment) {
           $any_effect = true;
         }
       } else if ($xaction->getIgnoreOnNoEffect()) {
         unset($xactions[$key]);
       } else {
         $no_effect[$key] = $xaction;
       }
       if ($xaction->hasComment()) {
         $has_comment = true;
       }
     }
 
     if (!$no_effect) {
       return $xactions;
     }
 
     if (!$this->getContinueOnNoEffect() && !$this->getIsPreview()) {
       throw new PhabricatorApplicationTransactionNoEffectException(
         $no_effect,
         $any_effect,
         $has_comment);
     }
 
     if (!$any_effect && !$has_comment) {
       // If we only have empty comment transactions, just drop them all.
       return array();
     }
 
     foreach ($no_effect as $key => $xaction) {
       if ($xaction->hasComment()) {
         $xaction->setTransactionType($type_comment);
         $xaction->setOldValue(null);
         $xaction->setNewValue(null);
       } else {
         unset($xactions[$key]);
       }
     }
 
     return $xactions;
   }
 
 
   /**
    * Hook for validating transactions. This callback will be invoked for each
    * available transaction type, even if an edit does not apply any transactions
    * of that type. This allows you to raise exceptions when required fields are
    * missing, by detecting that the object has no field value and there is no
    * transaction which sets one.
    *
    * @param PhabricatorLiskDAO Object being edited.
    * @param string Transaction type to validate.
    * @param list<PhabricatorApplicationTransaction> Transactions of given type,
    *   which may be empty if the edit does not apply any transactions of the
    *   given type.
    * @return list<PhabricatorApplicationTransactionValidationError> List of
    *   validation errors.
    */
   protected function validateTransaction(
     PhabricatorLiskDAO $object,
     $type,
     array $xactions) {
 
     $errors = array();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       $errors[] = $xtype->validateTransactions($object, $xactions);
     }
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         $errors[] = $this->validatePolicyTransaction(
           $object,
           $xactions,
           $type,
           PhabricatorPolicyCapability::CAN_VIEW);
         break;
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         $errors[] = $this->validatePolicyTransaction(
           $object,
           $xactions,
           $type,
           PhabricatorPolicyCapability::CAN_EDIT);
         break;
       case PhabricatorTransactions::TYPE_SPACE:
         $errors[] = $this->validateSpaceTransactions(
           $object,
           $xactions,
           $type);
         break;
       case PhabricatorTransactions::TYPE_SUBTYPE:
         $errors[] = $this->validateSubtypeTransactions(
           $object,
           $xactions,
           $type);
         break;
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $groups = array();
         foreach ($xactions as $xaction) {
           $groups[$xaction->getMetadataValue('customfield:key')][] = $xaction;
         }
 
         $field_list = PhabricatorCustomField::getObjectFields(
           $object,
           PhabricatorCustomField::ROLE_EDIT);
         $field_list->setViewer($this->getActor());
 
         $role_xactions = PhabricatorCustomField::ROLE_APPLICATIONTRANSACTIONS;
         foreach ($field_list->getFields() as $field) {
           if (!$field->shouldEnableForRole($role_xactions)) {
             continue;
           }
           $errors[] = $field->validateApplicationTransactions(
             $this,
             $type,
             idx($groups, $field->getFieldKey(), array()));
         }
         break;
     }
 
     return array_mergev($errors);
   }
 
   public function validatePolicyTransaction(
     PhabricatorLiskDAO $object,
     array $xactions,
     $transaction_type,
     $capability) {
 
     $actor = $this->requireActor();
     $errors = array();
     // Note $this->xactions is necessary; $xactions is $this->xactions of
     // $transaction_type
     $policy_object = $this->adjustObjectForPolicyChecks(
       $object,
       $this->xactions);
 
     // Make sure the user isn't editing away their ability to $capability this
     // object.
     foreach ($xactions as $xaction) {
       try {
         PhabricatorPolicyFilter::requireCapabilityWithForcedPolicy(
           $actor,
           $policy_object,
           $capability,
           $xaction->getNewValue());
       } catch (PhabricatorPolicyException $ex) {
         $errors[] = new PhabricatorApplicationTransactionValidationError(
           $transaction_type,
           pht('Invalid'),
           pht(
             'You can not select this %s policy, because you would no longer '.
             'be able to %s the object.',
             $capability,
             $capability),
           $xaction);
       }
     }
 
     if ($this->getIsNewObject()) {
       if (!$xactions) {
         $has_capability = PhabricatorPolicyFilter::hasCapability(
           $actor,
           $policy_object,
           $capability);
         if (!$has_capability) {
           $errors[] = new PhabricatorApplicationTransactionValidationError(
             $transaction_type,
             pht('Invalid'),
             pht(
               'The selected %s policy excludes you. Choose a %s policy '.
               'which allows you to %s the object.',
               $capability,
               $capability,
               $capability));
         }
       }
     }
 
     return $errors;
   }
 
 
   private function validateSpaceTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     $transaction_type) {
     $errors = array();
 
     $actor = $this->getActor();
 
     $has_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpacesExist($actor);
     $actor_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces($actor);
     $active_spaces = PhabricatorSpacesNamespaceQuery::getViewerActiveSpaces(
       $actor);
     foreach ($xactions as $xaction) {
       $space_phid = $xaction->getNewValue();
 
       if ($space_phid === null) {
         if (!$has_spaces) {
           // The install doesn't have any spaces, so this is fine.
           continue;
         }
 
         // The install has some spaces, so every object needs to be put
         // in a valid space.
         $errors[] = new PhabricatorApplicationTransactionValidationError(
           $transaction_type,
           pht('Invalid'),
           pht('You must choose a space for this object.'),
           $xaction);
         continue;
       }
 
       // If the PHID isn't `null`, it needs to be a valid space that the
       // viewer can see.
       if (empty($actor_spaces[$space_phid])) {
         $errors[] = new PhabricatorApplicationTransactionValidationError(
           $transaction_type,
           pht('Invalid'),
           pht(
             'You can not shift this object in the selected space, because '.
             'the space does not exist or you do not have access to it.'),
           $xaction);
       } else if (empty($active_spaces[$space_phid])) {
 
         // It's OK to edit objects in an archived space, so just move on if
         // we aren't adjusting the value.
         $old_space_phid = $this->getTransactionOldValue($object, $xaction);
         if ($space_phid == $old_space_phid) {
           continue;
         }
 
         $errors[] = new PhabricatorApplicationTransactionValidationError(
           $transaction_type,
           pht('Archived'),
           pht(
             'You can not shift this object into the selected space, because '.
             'the space is archived. Objects can not be created inside (or '.
             'moved into) archived spaces.'),
           $xaction);
       }
     }
 
     return $errors;
   }
 
   private function validateSubtypeTransactions(
     PhabricatorLiskDAO $object,
     array $xactions,
     $transaction_type) {
     $errors = array();
 
     $map = $object->newEditEngineSubtypeMap();
     $old = $object->getEditEngineSubtype();
     foreach ($xactions as $xaction) {
       $new = $xaction->getNewValue();
 
       if ($old == $new) {
         continue;
       }
 
       if (!isset($map[$new])) {
         $errors[] = new PhabricatorApplicationTransactionValidationError(
           $transaction_type,
           pht('Invalid'),
           pht(
             'The subtype "%s" is not a valid subtype.',
             $new),
           $xaction);
         continue;
       }
     }
 
     return $errors;
   }
 
   protected function adjustObjectForPolicyChecks(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $copy = clone $object;
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_SUBSCRIBERS:
           $clone_xaction = clone $xaction;
           $clone_xaction->setOldValue(array_values($this->subscribers));
           $clone_xaction->setNewValue(
             $this->getPHIDTransactionNewValue(
               $clone_xaction));
 
           PhabricatorPolicyRule::passTransactionHintToRule(
             $copy,
             new PhabricatorSubscriptionsSubscribersPolicyRule(),
             array_fuse($clone_xaction->getNewValue()));
 
           break;
         case PhabricatorTransactions::TYPE_SPACE:
           $space_phid = $this->getTransactionNewValue($object, $xaction);
           $copy->setSpacePHID($space_phid);
           break;
       }
     }
 
     return $copy;
   }
 
   protected function validateAllTransactions(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return array();
   }
 
   /**
    * Check for a missing text field.
    *
    * A text field is missing if the object has no value and there are no
    * transactions which set a value, or if the transactions remove the value.
    * This method is intended to make implementing @{method:validateTransaction}
    * more convenient:
    *
    *   $missing = $this->validateIsEmptyTextField(
    *     $object->getName(),
    *     $xactions);
    *
    * This will return `true` if the net effect of the object and transactions
    * is an empty field.
    *
    * @param wild Current field value.
    * @param list<PhabricatorApplicationTransaction> Transactions editing the
    *          field.
    * @return bool True if the field will be an empty text field after edits.
    */
   protected function validateIsEmptyTextField($field_value, array $xactions) {
     if (strlen($field_value) && empty($xactions)) {
       return false;
     }
 
     if ($xactions && strlen(last($xactions)->getNewValue())) {
       return false;
     }
 
     return true;
   }
 
 
 /* -(  Implicit CCs  )------------------------------------------------------- */
 
 
   /**
    * When a user interacts with an object, we might want to add them to CC.
    */
   final public function applyImplicitCC(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if (!($object instanceof PhabricatorSubscribableInterface)) {
       // If the object isn't subscribable, we can't CC them.
       return $xactions;
     }
 
     $actor_phid = $this->getActingAsPHID();
 
     $type_user = PhabricatorPeopleUserPHIDType::TYPECONST;
     if (phid_get_type($actor_phid) != $type_user) {
       // Transactions by application actors like Herald, Harbormaster and
       // Diffusion should not CC the applications.
       return $xactions;
     }
 
     if ($object->isAutomaticallySubscribed($actor_phid)) {
       // If they're auto-subscribed, don't CC them.
       return $xactions;
     }
 
     $should_cc = false;
     foreach ($xactions as $xaction) {
       if ($this->shouldImplyCC($object, $xaction)) {
         $should_cc = true;
         break;
       }
     }
 
     if (!$should_cc) {
       // Only some types of actions imply a CC (like adding a comment).
       return $xactions;
     }
 
     if ($object->getPHID()) {
       if (isset($this->subscribers[$actor_phid])) {
         // If the user is already subscribed, don't implicitly CC them.
         return $xactions;
       }
 
       $unsub = PhabricatorEdgeQuery::loadDestinationPHIDs(
         $object->getPHID(),
         PhabricatorObjectHasUnsubscriberEdgeType::EDGECONST);
       $unsub = array_fuse($unsub);
       if (isset($unsub[$actor_phid])) {
         // If the user has previously unsubscribed from this object explicitly,
         // don't implicitly CC them.
         return $xactions;
       }
     }
 
     $xaction = newv(get_class(head($xactions)), array());
     $xaction->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS);
     $xaction->setNewValue(array('+' => array($actor_phid)));
 
     array_unshift($xactions, $xaction);
 
     return $xactions;
   }
 
   protected function shouldImplyCC(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     return $xaction->isCommentTransaction();
   }
 
 
 /* -(  Sending Mail  )------------------------------------------------------- */
 
 
   /**
    * @task mail
    */
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return false;
   }
 
 
   /**
    * @task mail
    */
   private function buildMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $email_to = $this->mailToPHIDs;
     $email_cc = $this->mailCCPHIDs;
     $email_cc = array_merge($email_cc, $this->heraldEmailPHIDs);
 
+    $unexpandable = $this->mailUnexpandablePHIDs;
+    if (!is_array($unexpandable)) {
+      $unexpandable = array();
+    }
+
     $targets = $this->buildReplyHandler($object)
+      ->setUnexpandablePHIDs($unexpandable)
       ->getMailTargets($email_to, $email_cc);
 
     // Set this explicitly before we start swapping out the effective actor.
     $this->setActingAsPHID($this->getActingAsPHID());
 
     $messages = array();
     foreach ($targets as $target) {
       $original_actor = $this->getActor();
 
       $viewer = $target->getViewer();
       $this->setActor($viewer);
       $locale = PhabricatorEnv::beginScopedLocale($viewer->getTranslation());
 
       $caught = null;
       $mail = null;
       try {
         // Reload handles for the new viewer.
         $this->loadHandles($xactions);
 
         $mail = $this->buildMailForTarget($object, $xactions, $target);
 
         if ($mail) {
           if ($this->mustEncrypt) {
             $mail
               ->setMustEncrypt(true)
               ->setMustEncryptReasons($this->mustEncrypt);
           }
         }
       } catch (Exception $ex) {
         $caught = $ex;
       }
 
       $this->setActor($original_actor);
       unset($locale);
 
       if ($caught) {
         throw $ex;
       }
 
       if ($mail) {
         $messages[] = $mail;
       }
     }
 
     $this->runHeraldMailRules($messages);
 
     return $messages;
   }
 
   protected function getTransactionsForMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $xactions;
   }
 
   private function buildMailForTarget(
     PhabricatorLiskDAO $object,
     array $xactions,
     PhabricatorMailTarget $target) {
 
     // Check if any of the transactions are visible for this viewer. If we
     // don't have any visible transactions, don't send the mail.
 
     $any_visible = false;
     foreach ($xactions as $xaction) {
       if (!$xaction->shouldHideForMail($xactions)) {
         $any_visible = true;
         break;
       }
     }
 
     if (!$any_visible) {
       return null;
     }
 
     $mail_xactions = $this->getTransactionsForMail($object, $xactions);
 
     $mail = $this->buildMailTemplate($object);
     $body = $this->buildMailBody($object, $mail_xactions);
 
     $mail_tags = $this->getMailTags($object, $mail_xactions);
     $action = $this->getMailAction($object, $mail_xactions);
     $stamps = $this->generateMailStamps($object, $this->mailStamps);
 
     if (PhabricatorEnv::getEnvConfig('metamta.email-preferences')) {
       $this->addEmailPreferenceSectionToMailBody(
         $body,
         $object,
         $mail_xactions);
     }
 
     $mail
       ->setSensitiveContent(false)
       ->setFrom($this->getActingAsPHID())
       ->setSubjectPrefix($this->getMailSubjectPrefix())
       ->setVarySubjectPrefix('['.$action.']')
       ->setThreadID($this->getMailThreadID($object), $this->getIsNewObject())
       ->setRelatedPHID($object->getPHID())
       ->setExcludeMailRecipientPHIDs($this->getExcludeMailRecipientPHIDs())
       ->setForceHeraldMailRecipientPHIDs($this->heraldForcedEmailPHIDs)
       ->setMailTags($mail_tags)
       ->setIsBulk(true)
       ->setBody($body->render())
       ->setHTMLBody($body->renderHTML());
 
     foreach ($body->getAttachments() as $attachment) {
       $mail->addAttachment($attachment);
     }
 
     if ($this->heraldHeader) {
       $mail->addHeader('X-Herald-Rules', $this->heraldHeader);
     }
 
     if ($object instanceof PhabricatorProjectInterface) {
       $this->addMailProjectMetadata($object, $mail);
     }
 
     if ($this->getParentMessageID()) {
       $mail->setParentMessageID($this->getParentMessageID());
     }
 
     // If we have stamps, attach the raw dictionary version (not the actual
     // objects) to the mail so that debugging tools can see what we used to
     // render the final list.
     if ($this->mailStamps) {
       $mail->setMailStampMetadata($this->mailStamps);
     }
 
     // If we have rendered stamps, attach them to the mail.
     if ($stamps) {
       $mail->setMailStamps($stamps);
     }
 
     return $target->willSendMail($mail);
   }
 
   private function addMailProjectMetadata(
     PhabricatorLiskDAO $object,
     PhabricatorMetaMTAMail $template) {
 
     $project_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
       $object->getPHID(),
       PhabricatorProjectObjectHasProjectEdgeType::EDGECONST);
 
     if (!$project_phids) {
       return;
     }
 
     // TODO: This viewer isn't quite right. It would be slightly better to use
     // the mail recipient, but that's not very easy given the way rendering
     // works today.
 
     $handles = id(new PhabricatorHandleQuery())
       ->setViewer($this->requireActor())
       ->withPHIDs($project_phids)
       ->execute();
 
     $project_tags = array();
     foreach ($handles as $handle) {
       if (!$handle->isComplete()) {
         continue;
       }
       $project_tags[] = '<'.$handle->getObjectName().'>';
     }
 
     if (!$project_tags) {
       return;
     }
 
     $project_tags = implode(', ', $project_tags);
     $template->addHeader('X-Phabricator-Projects', $project_tags);
   }
 
 
   protected function getMailThreadID(PhabricatorLiskDAO $object) {
     return $object->getPHID();
   }
 
 
   /**
    * @task mail
    */
   protected function getStrongestAction(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return last(msort($xactions, 'getActionStrength'));
   }
 
 
   /**
    * @task mail
    */
   protected function buildReplyHandler(PhabricatorLiskDAO $object) {
     throw new Exception(pht('Capability not supported.'));
   }
 
   /**
    * @task mail
    */
   protected function getMailSubjectPrefix() {
     throw new Exception(pht('Capability not supported.'));
   }
 
 
   /**
    * @task mail
    */
   protected function getMailTags(
     PhabricatorLiskDAO $object,
     array $xactions) {
     $tags = array();
 
     foreach ($xactions as $xaction) {
       $tags[] = $xaction->getMailTags();
     }
 
     return array_mergev($tags);
   }
 
   /**
    * @task mail
    */
   public function getMailTagsMap() {
     // TODO: We should move shared mail tags, like "comment", here.
     return array();
   }
 
 
   /**
    * @task mail
    */
   protected function getMailAction(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return $this->getStrongestAction($object, $xactions)->getActionName();
   }
 
 
   /**
    * @task mail
    */
   protected function buildMailTemplate(PhabricatorLiskDAO $object) {
     throw new Exception(pht('Capability not supported.'));
   }
 
 
   /**
    * @task mail
    */
   protected function getMailTo(PhabricatorLiskDAO $object) {
     throw new Exception(pht('Capability not supported.'));
   }
 
 
+  protected function newMailUnexpandablePHIDs(PhabricatorLiskDAO $object) {
+    return array();
+  }
+
+
   /**
    * @task mail
    */
   protected function getMailCC(PhabricatorLiskDAO $object) {
     $phids = array();
     $has_support = false;
 
     if ($object instanceof PhabricatorSubscribableInterface) {
       $phid = $object->getPHID();
       $phids[] = PhabricatorSubscribersQuery::loadSubscribersForPHID($phid);
       $has_support = true;
     }
 
     if ($object instanceof PhabricatorProjectInterface) {
       $project_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
         $object->getPHID(),
         PhabricatorProjectObjectHasProjectEdgeType::EDGECONST);
 
       if ($project_phids) {
         $projects = id(new PhabricatorProjectQuery())
           ->setViewer(PhabricatorUser::getOmnipotentUser())
           ->withPHIDs($project_phids)
           ->needWatchers(true)
           ->execute();
 
         $watcher_phids = array();
         foreach ($projects as $project) {
           foreach ($project->getAllAncestorWatcherPHIDs() as $phid) {
             $watcher_phids[$phid] = $phid;
           }
         }
 
         if ($watcher_phids) {
           // We need to do a visibility check for all the watchers, as
           // watching a project is not a guarantee that you can see objects
           // associated with it.
           $users = id(new PhabricatorPeopleQuery())
             ->setViewer($this->requireActor())
             ->withPHIDs($watcher_phids)
             ->execute();
 
           $watchers = array();
           foreach ($users as $user) {
             $can_see = PhabricatorPolicyFilter::hasCapability(
               $user,
               $object,
               PhabricatorPolicyCapability::CAN_VIEW);
             if ($can_see) {
               $watchers[] = $user->getPHID();
             }
           }
           $phids[] = $watchers;
         }
       }
 
       $has_support = true;
     }
 
     if (!$has_support) {
       throw new Exception(
         pht('The object being edited does not implement any standard '.
           'interfaces (like PhabricatorSubscribableInterface) which allow '.
           'CCs to be generated automatically. Override the "getMailCC()" '.
           'method and generate CCs explicitly.'));
     }
 
     return array_mergev($phids);
   }
 
 
   /**
    * @task mail
    */
   protected function buildMailBody(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $body = new PhabricatorMetaMTAMailBody();
     $body->setViewer($this->requireActor());
 
     $this->addHeadersAndCommentsToMailBody($body, $xactions);
     $this->addCustomFieldsToMailBody($body, $object, $xactions);
     return $body;
   }
 
 
   /**
    * @task mail
    */
   protected function addEmailPreferenceSectionToMailBody(
     PhabricatorMetaMTAMailBody $body,
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $href = PhabricatorEnv::getProductionURI(
       '/settings/panel/emailpreferences/');
     $body->addLinkSection(pht('EMAIL PREFERENCES'), $href);
   }
 
 
   /**
    * @task mail
    */
   protected function addHeadersAndCommentsToMailBody(
     PhabricatorMetaMTAMailBody $body,
     array $xactions,
     $object_label = null,
     $object_href = null) {
 
     $headers = array();
     $headers_html = array();
     $comments = array();
     $details = array();
 
     foreach ($xactions as $xaction) {
       if ($xaction->shouldHideForMail($xactions)) {
         continue;
       }
 
       $header = $xaction->getTitleForMail();
       if ($header !== null) {
         $headers[] = $header;
       }
 
       $header_html = $xaction->getTitleForHTMLMail();
       if ($header_html !== null) {
         $headers_html[] = $header_html;
       }
 
       $comment = $xaction->getBodyForMail();
       if ($comment !== null) {
         $comments[] = $comment;
       }
 
       if ($xaction->hasChangeDetailsForMail()) {
         $details[] = $xaction;
       }
     }
 
     $headers_text = implode("\n", $headers);
     $body->addRawPlaintextSection($headers_text);
 
     $headers_html = phutil_implode_html(phutil_tag('br'), $headers_html);
 
     $header_button = null;
     if ($object_label !== null) {
       $button_style = array(
         'text-decoration: none;',
         'padding: 4px 8px;',
         'margin: 0 8px 8px;',
         'float: right;',
         'color: #464C5C;',
         'font-weight: bold;',
         'border-radius: 3px;',
         'background-color: #F7F7F9;',
         'background-image: linear-gradient(to bottom,#fff,#f1f0f1);',
         'display: inline-block;',
         'border: 1px solid rgba(71,87,120,.2);',
       );
 
       $header_button = phutil_tag(
         'a',
         array(
           'style' => implode(' ', $button_style),
           'href' => $object_href,
         ),
         $object_label);
     }
 
     $xactions_style = array(
     );
 
     $header_action = phutil_tag(
       'td',
       array(),
       $header_button);
 
     $header_action = phutil_tag(
       'td',
       array(
         'style' => implode(' ', $xactions_style),
       ),
       array(
         $headers_html,
         // Add an extra newline to prevent the "View Object" button from
         // running into the transaction text in Mail.app text snippet
         // previews.
         "\n",
       ));
 
     $headers_html = phutil_tag(
       'table',
       array(),
       phutil_tag('tr', array(), array($header_action, $header_button)));
 
     $body->addRawHTMLSection($headers_html);
 
     foreach ($comments as $comment) {
       $body->addRemarkupSection(null, $comment);
     }
 
     foreach ($details as $xaction) {
       $details = $xaction->renderChangeDetailsForMail($body->getViewer());
       if ($details !== null) {
         $label = $this->getMailDiffSectionHeader($xaction);
         $body->addHTMLSection($label, $details);
       }
     }
 
   }
 
   private function getMailDiffSectionHeader($xaction) {
     $type = $xaction->getTransactionType();
 
     $xtype = $this->getModularTransactionType($type);
     if ($xtype) {
       return $xtype->getMailDiffSectionHeader();
     }
 
     return pht('EDIT DETAILS');
   }
 
   /**
    * @task mail
    */
   protected function addCustomFieldsToMailBody(
     PhabricatorMetaMTAMailBody $body,
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if ($object instanceof PhabricatorCustomFieldInterface) {
       $field_list = PhabricatorCustomField::getObjectFields(
         $object,
         PhabricatorCustomField::ROLE_TRANSACTIONMAIL);
       $field_list->setViewer($this->getActor());
       $field_list->readFieldsFromStorage($object);
 
       foreach ($field_list->getFields() as $field) {
         $field->updateTransactionMailBody(
           $body,
           $this,
           $xactions);
       }
     }
   }
 
 
   /**
    * @task mail
    */
   private function runHeraldMailRules(array $messages) {
     foreach ($messages as $message) {
       $engine = new HeraldEngine();
       $adapter = id(new PhabricatorMailOutboundMailHeraldAdapter())
         ->setObject($message);
 
       $rules = $engine->loadRulesForAdapter($adapter);
       $effects = $engine->applyRules($rules, $adapter);
       $engine->applyEffects($effects, $adapter, $rules);
     }
   }
 
 
 /* -(  Publishing Feed Stories  )-------------------------------------------- */
 
 
   /**
    * @task feed
    */
   protected function shouldPublishFeedStory(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return false;
   }
 
 
   /**
    * @task feed
    */
   protected function getFeedStoryType() {
     return 'PhabricatorApplicationTransactionFeedStory';
   }
 
 
   /**
    * @task feed
    */
   protected function getFeedRelatedPHIDs(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $phids = array(
       $object->getPHID(),
       $this->getActingAsPHID(),
     );
 
     if ($object instanceof PhabricatorProjectInterface) {
       $project_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
         $object->getPHID(),
         PhabricatorProjectObjectHasProjectEdgeType::EDGECONST);
       foreach ($project_phids as $project_phid) {
         $phids[] = $project_phid;
       }
     }
 
     return $phids;
   }
 
 
   /**
    * @task feed
    */
   protected function getFeedNotifyPHIDs(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     return array_unique(array_merge(
       $this->getMailTo($object),
       $this->getMailCC($object)));
   }
 
 
   /**
    * @task feed
    */
   protected function getFeedStoryData(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $xactions = msort($xactions, 'getActionStrength');
     $xactions = array_reverse($xactions);
 
     return array(
       'objectPHID'        => $object->getPHID(),
       'transactionPHIDs'  => mpull($xactions, 'getPHID'),
     );
   }
 
 
   /**
    * @task feed
    */
   protected function publishFeedStory(
     PhabricatorLiskDAO $object,
     array $xactions,
     array $mailed_phids) {
 
     $xactions = mfilter($xactions, 'shouldHideForFeed', true);
 
     if (!$xactions) {
       return;
     }
 
     $related_phids = $this->feedRelatedPHIDs;
     $subscribed_phids = $this->feedNotifyPHIDs;
 
     $story_type = $this->getFeedStoryType();
     $story_data = $this->getFeedStoryData($object, $xactions);
 
     id(new PhabricatorFeedStoryPublisher())
       ->setStoryType($story_type)
       ->setStoryData($story_data)
       ->setStoryTime(time())
       ->setStoryAuthorPHID($this->getActingAsPHID())
       ->setRelatedPHIDs($related_phids)
       ->setPrimaryObjectPHID($object->getPHID())
       ->setSubscribedPHIDs($subscribed_phids)
       ->setMailRecipientPHIDs($mailed_phids)
       ->setMailTags($this->getMailTags($object, $xactions))
       ->publish();
   }
 
 
 /* -(  Search Index  )------------------------------------------------------- */
 
 
   /**
    * @task search
    */
   protected function supportsSearch() {
     return false;
   }
 
 
 /* -(  Herald Integration )-------------------------------------------------- */
 
 
   protected function shouldApplyHeraldRules(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return false;
   }
 
   protected function buildHeraldAdapter(
     PhabricatorLiskDAO $object,
     array $xactions) {
     throw new Exception(pht('No herald adapter specified.'));
   }
 
   private function setHeraldAdapter(HeraldAdapter $adapter) {
     $this->heraldAdapter = $adapter;
     return $this;
   }
 
   protected function getHeraldAdapter() {
     return $this->heraldAdapter;
   }
 
   private function setHeraldTranscript(HeraldTranscript $transcript) {
     $this->heraldTranscript = $transcript;
     return $this;
   }
 
   protected function getHeraldTranscript() {
     return $this->heraldTranscript;
   }
 
   private function applyHeraldRules(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $adapter = $this->buildHeraldAdapter($object, $xactions)
       ->setContentSource($this->getContentSource())
       ->setIsNewObject($this->getIsNewObject())
       ->setAppliedTransactions($xactions);
 
     if ($this->getApplicationEmail()) {
       $adapter->setApplicationEmail($this->getApplicationEmail());
     }
 
     // If this editor is operating in silent mode, tell Herald that we aren't
     // going to send any mail. This allows it to skip "the first time this
     // rule matches, send me an email" rules which would otherwise match even
     // though we aren't going to send any mail.
     if ($this->getIsSilent()) {
       $adapter->setForbiddenAction(
         HeraldMailableState::STATECONST,
         HeraldCoreStateReasons::REASON_SILENT);
     }
 
     $xscript = HeraldEngine::loadAndApplyRules($adapter);
 
     $this->setHeraldAdapter($adapter);
     $this->setHeraldTranscript($xscript);
 
     if ($adapter instanceof HarbormasterBuildableAdapterInterface) {
       HarbormasterBuildable::applyBuildPlans(
         $adapter->getHarbormasterBuildablePHID(),
         $adapter->getHarbormasterContainerPHID(),
         $adapter->getQueuedHarbormasterBuildRequests());
     }
 
     $this->mustEncrypt = $adapter->getMustEncryptReasons();
 
     return array_merge(
       $this->didApplyHeraldRules($object, $adapter, $xscript),
       $adapter->getQueuedTransactions());
   }
 
   protected function didApplyHeraldRules(
     PhabricatorLiskDAO $object,
     HeraldAdapter $adapter,
     HeraldTranscript $transcript) {
     return array();
   }
 
 
 /* -(  Custom Fields  )------------------------------------------------------ */
 
 
   /**
    * @task customfield
    */
   private function getCustomFieldForTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $field_key = $xaction->getMetadataValue('customfield:key');
     if (!$field_key) {
       throw new Exception(
         pht(
         "Custom field transaction has no '%s'!",
         'customfield:key'));
     }
 
     $field = PhabricatorCustomField::getObjectField(
       $object,
       PhabricatorCustomField::ROLE_APPLICATIONTRANSACTIONS,
       $field_key);
 
     if (!$field) {
       throw new Exception(
         pht(
           "Custom field transaction has invalid '%s'; field '%s' ".
           "is disabled or does not exist.",
           'customfield:key',
           $field_key));
     }
 
     if (!$field->shouldAppearInApplicationTransactions()) {
       throw new Exception(
         pht(
           "Custom field transaction '%s' does not implement ".
           "integration for %s.",
           $field_key,
           'ApplicationTransactions'));
     }
 
     $field->setViewer($this->getActor());
 
     return $field;
   }
 
 
 /* -(  Files  )-------------------------------------------------------------- */
 
 
   /**
    * Extract the PHIDs of any files which these transactions attach.
    *
    * @task files
    */
   private function extractFilePHIDs(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $changes = $this->getRemarkupChanges($xactions);
     $blocks = mpull($changes, 'getNewValue');
 
     $phids = array();
     if ($blocks) {
       $phids[] = PhabricatorMarkupEngine::extractFilePHIDsFromEmbeddedFiles(
         $this->getActor(),
         $blocks);
     }
 
     foreach ($xactions as $xaction) {
       $type = $xaction->getTransactionType();
 
       $xtype = $this->getModularTransactionType($type);
       if ($xtype) {
         $phids[] = $xtype->extractFilePHIDs($object, $xaction->getNewValue());
       } else {
         $phids[] = $this->extractFilePHIDsFromCustomTransaction(
           $object,
           $xaction);
       }
     }
 
     $phids = array_unique(array_filter(array_mergev($phids)));
     if (!$phids) {
       return array();
     }
 
     // Only let a user attach files they can actually see, since this would
     // otherwise let you access any file by attaching it to an object you have
     // view permission on.
 
     $files = id(new PhabricatorFileQuery())
       ->setViewer($this->getActor())
       ->withPHIDs($phids)
       ->execute();
 
     return mpull($files, 'getPHID');
   }
 
   /**
    * @task files
    */
   protected function extractFilePHIDsFromCustomTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
     return array();
   }
 
 
   /**
    * @task files
    */
   private function attachFiles(
     PhabricatorLiskDAO $object,
     array $file_phids) {
 
     if (!$file_phids) {
       return;
     }
 
     $editor = new PhabricatorEdgeEditor();
 
     $src = $object->getPHID();
     $type = PhabricatorObjectHasFileEdgeType::EDGECONST;
     foreach ($file_phids as $dst) {
       $editor->addEdge($src, $type, $dst);
     }
 
     $editor->save();
   }
 
   private function applyInverseEdgeTransactions(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction,
     $inverse_type) {
 
     $old = $xaction->getOldValue();
     $new = $xaction->getNewValue();
 
     $add = array_keys(array_diff_key($new, $old));
     $rem = array_keys(array_diff_key($old, $new));
 
     $add = array_fuse($add);
     $rem = array_fuse($rem);
     $all = $add + $rem;
 
     $nodes = id(new PhabricatorObjectQuery())
       ->setViewer($this->requireActor())
       ->withPHIDs($all)
       ->execute();
 
     foreach ($nodes as $node) {
       if (!($node instanceof PhabricatorApplicationTransactionInterface)) {
         continue;
       }
 
       if ($node instanceof PhabricatorUser) {
         // TODO: At least for now, don't record inverse edge transactions
         // for users (for example, "alincoln joined project X"): Feed fills
         // this role instead.
         continue;
       }
 
       $editor = $node->getApplicationTransactionEditor();
       $template = $node->getApplicationTransactionTemplate();
       $target = $node->getApplicationTransactionObject();
 
       if (isset($add[$node->getPHID()])) {
         $edge_edit_type = '+';
       } else {
         $edge_edit_type = '-';
       }
 
       $template
         ->setTransactionType($xaction->getTransactionType())
         ->setMetadataValue('edge:type', $inverse_type)
         ->setNewValue(
           array(
             $edge_edit_type => array($object->getPHID() => $object->getPHID()),
           ));
 
       $editor
         ->setContinueOnNoEffect(true)
         ->setContinueOnMissingFields(true)
         ->setParentMessageID($this->getParentMessageID())
         ->setIsInverseEdgeEditor(true)
         ->setActor($this->requireActor())
         ->setActingAsPHID($this->getActingAsPHID())
         ->setContentSource($this->getContentSource());
 
       $editor->applyTransactions($target, array($template));
     }
   }
 
 
 /* -(  Workers  )------------------------------------------------------------ */
 
 
   /**
    * Load any object state which is required to publish transactions.
    *
    * This hook is invoked in the main process before we compute data related
    * to publishing transactions (like email "To" and "CC" lists), and again in
    * the worker before publishing occurs.
    *
    * @return object Publishable object.
    * @task workers
    */
   protected function willPublish(PhabricatorLiskDAO $object, array $xactions) {
     return $object;
   }
 
 
   /**
    * Convert the editor state to a serializable dictionary which can be passed
    * to a worker.
    *
    * This data will be loaded with @{method:loadWorkerState} in the worker.
    *
    * @return dict<string, wild> Serializable editor state.
    * @task workers
    */
   final private function getWorkerState() {
     $state = array();
     foreach ($this->getAutomaticStateProperties() as $property) {
       $state[$property] = $this->$property;
     }
 
     $custom_state = $this->getCustomWorkerState();
     $custom_encoding = $this->getCustomWorkerStateEncoding();
 
     $state += array(
       'excludeMailRecipientPHIDs' => $this->getExcludeMailRecipientPHIDs(),
       'custom' => $this->encodeStateForStorage($custom_state, $custom_encoding),
       'custom.encoding' => $custom_encoding,
     );
 
     return $state;
   }
 
 
   /**
    * Hook; return custom properties which need to be passed to workers.
    *
    * @return dict<string, wild> Custom properties.
    * @task workers
    */
   protected function getCustomWorkerState() {
     return array();
   }
 
 
   /**
    * Hook; return storage encoding for custom properties which need to be
    * passed to workers.
    *
    * This primarily allows binary data to be passed to workers and survive
    * JSON encoding.
    *
    * @return dict<string, string> Property encodings.
    * @task workers
    */
   protected function getCustomWorkerStateEncoding() {
     return array();
   }
 
 
   /**
    * Load editor state using a dictionary emitted by @{method:getWorkerState}.
    *
    * This method is used to load state when running worker operations.
    *
    * @param dict<string, wild> Editor state, from @{method:getWorkerState}.
    * @return this
    * @task workers
    */
   final public function loadWorkerState(array $state) {
     foreach ($this->getAutomaticStateProperties() as $property) {
       $this->$property = idx($state, $property);
     }
 
     $exclude = idx($state, 'excludeMailRecipientPHIDs', array());
     $this->setExcludeMailRecipientPHIDs($exclude);
 
     $custom_state = idx($state, 'custom', array());
     $custom_encodings = idx($state, 'custom.encoding', array());
     $custom = $this->decodeStateFromStorage($custom_state, $custom_encodings);
 
     $this->loadCustomWorkerState($custom);
 
     return $this;
   }
 
 
   /**
    * Hook; set custom properties on the editor from data emitted by
    * @{method:getCustomWorkerState}.
    *
    * @param dict<string, wild> Custom state,
    *   from @{method:getCustomWorkerState}.
    * @return this
    * @task workers
    */
   protected function loadCustomWorkerState(array $state) {
     return $this;
   }
 
 
   /**
    * Get a list of object properties which should be automatically sent to
    * workers in the state data.
    *
    * These properties will be automatically stored and loaded by the editor in
    * the worker.
    *
    * @return list<string> List of properties.
    * @task workers
    */
   private function getAutomaticStateProperties() {
     return array(
       'parentMessageID',
       'isNewObject',
       'heraldEmailPHIDs',
       'heraldForcedEmailPHIDs',
       'heraldHeader',
       'mailToPHIDs',
       'mailCCPHIDs',
       'feedNotifyPHIDs',
       'feedRelatedPHIDs',
       'feedShouldPublish',
       'mailShouldSend',
       'mustEncrypt',
       'mailStamps',
+      'mailUnexpandablePHIDs',
     );
   }
 
   /**
    * Apply encodings prior to storage.
    *
    * See @{method:getCustomWorkerStateEncoding}.
    *
    * @param map<string, wild> Map of values to encode.
    * @param map<string, string> Map of encodings to apply.
    * @return map<string, wild> Map of encoded values.
    * @task workers
    */
   final private function encodeStateForStorage(
     array $state,
     array $encodings) {
 
     foreach ($state as $key => $value) {
       $encoding = idx($encodings, $key);
       switch ($encoding) {
         case self::STORAGE_ENCODING_BINARY:
           // The mechanics of this encoding (serialize + base64) are a little
           // awkward, but it allows us encode arrays and still be JSON-safe
           // with binary data.
 
           $value = @serialize($value);
           if ($value === false) {
             throw new Exception(
               pht(
                 'Failed to serialize() value for key "%s".',
                 $key));
           }
 
           $value = base64_encode($value);
           if ($value === false) {
             throw new Exception(
               pht(
                 'Failed to base64 encode value for key "%s".',
                 $key));
           }
           break;
       }
       $state[$key] = $value;
     }
 
     return $state;
   }
 
 
   /**
    * Undo storage encoding applied when storing state.
    *
    * See @{method:getCustomWorkerStateEncoding}.
    *
    * @param map<string, wild> Map of encoded values.
    * @param map<string, string> Map of encodings.
    * @return map<string, wild> Map of decoded values.
    * @task workers
    */
   final private function decodeStateFromStorage(
     array $state,
     array $encodings) {
 
     foreach ($state as $key => $value) {
       $encoding = idx($encodings, $key);
       switch ($encoding) {
         case self::STORAGE_ENCODING_BINARY:
           $value = base64_decode($value);
           if ($value === false) {
             throw new Exception(
               pht(
                 'Failed to base64_decode() value for key "%s".',
                 $key));
           }
 
           $value = unserialize($value);
           break;
       }
       $state[$key] = $value;
     }
 
     return $state;
   }
 
 
   /**
    * Remove conflicts from a list of projects.
    *
    * Objects aren't allowed to be tagged with multiple milestones in the same
    * group, nor projects such that one tag is the ancestor of any other tag.
    * If the list of PHIDs include mutually exclusive projects, remove the
    * conflicting projects.
    *
    * @param list<phid> List of project PHIDs.
    * @return list<phid> List with conflicts removed.
    */
   private function applyProjectConflictRules(array $phids) {
     if (!$phids) {
       return array();
     }
 
     // Overall, the last project in the list wins in cases of conflict (so when
     // you add something, the thing you just added sticks and removes older
     // values).
 
     // Beyond that, there are two basic cases:
 
     // Milestones: An object can't be in "A > Sprint 3" and "A > Sprint 4".
     // If multiple projects are milestones of the same parent, we only keep the
     // last one.
 
     // Ancestor: You can't be in "A" and "A > B". If "A > B" comes later
     // in the list, we remove "A" and keep "A > B". If "A" comes later, we
     // remove "A > B" and keep "A".
 
     // Note that it's OK to be in "A > B" and "A > C". There's only a conflict
     // if one project is an ancestor of another. It's OK to have something
     // tagged with multiple projects which share a common ancestor, so long as
     // they are not mutual ancestors.
 
     $viewer = PhabricatorUser::getOmnipotentUser();
 
     $projects = id(new PhabricatorProjectQuery())
       ->setViewer($viewer)
       ->withPHIDs(array_keys($phids))
       ->execute();
     $projects = mpull($projects, null, 'getPHID');
 
     // We're going to build a map from each project with milestones to the last
     // milestone in the list. This last milestone is the milestone we'll keep.
     $milestone_map = array();
 
     // We're going to build a set of the projects which have no descendants
     // later in the list. This allows us to apply both ancestor rules.
     $ancestor_map = array();
 
     foreach ($phids as $phid => $ignored) {
       $project = idx($projects, $phid);
       if (!$project) {
         continue;
       }
 
       // This is the last milestone we've seen, so set it as the selection for
       // the project's parent. This might be setting a new value or overwriting
       // an earlier value.
       if ($project->isMilestone()) {
         $parent_phid = $project->getParentProjectPHID();
         $milestone_map[$parent_phid] = $phid;
       }
 
       // Since this is the last item in the list we've examined so far, add it
       // to the set of projects with no later descendants.
       $ancestor_map[$phid] = $phid;
 
       // Remove any ancestors from the set, since this is a later descendant.
       foreach ($project->getAncestorProjects() as $ancestor) {
         $ancestor_phid = $ancestor->getPHID();
         unset($ancestor_map[$ancestor_phid]);
       }
     }
 
     // Now that we've built the maps, we can throw away all the projects which
     // have conflicts.
     foreach ($phids as $phid => $ignored) {
       $project = idx($projects, $phid);
 
       if (!$project) {
         // If a PHID is invalid, we just leave it as-is. We could clean it up,
         // but leaving it untouched is less likely to cause collateral damage.
         continue;
       }
 
       // If this was a milestone, check if it was the last milestone from its
       // group in the list. If not, remove it from the list.
       if ($project->isMilestone()) {
         $parent_phid = $project->getParentProjectPHID();
         if ($milestone_map[$parent_phid] !== $phid) {
           unset($phids[$phid]);
           continue;
         }
       }
 
       // If a later project in the list is a subproject of this one, it will
       // have removed ancestors from the map. If this project does not point
       // at itself in the ancestor map, it should be discarded in favor of a
       // subproject that comes later.
       if (idx($ancestor_map, $phid) !== $phid) {
         unset($phids[$phid]);
         continue;
       }
 
       // If a later project in the list is an ancestor of this one, it will
       // have added itself to the map. If any ancestor of this project points
       // at itself in the map, this project should be discarded in favor of
       // that later ancestor.
       foreach ($project->getAncestorProjects() as $ancestor) {
         $ancestor_phid = $ancestor->getPHID();
         if (isset($ancestor_map[$ancestor_phid])) {
           unset($phids[$phid]);
           continue 2;
         }
       }
     }
 
     return $phids;
   }
 
   /**
    * When the view policy for an object is changed, scramble the secret keys
    * for attached files to invalidate existing URIs.
    */
   private function scrambleFileSecrets($object) {
     // If this is a newly created object, we don't need to scramble anything
     // since it couldn't have been previously published.
     if ($this->getIsNewObject()) {
       return;
     }
 
     // If the object is a file itself, scramble it.
     if ($object instanceof PhabricatorFile) {
       if ($this->shouldScramblePolicy($object->getViewPolicy())) {
         $object->scrambleSecret();
         $object->save();
       }
     }
 
     $phid = $object->getPHID();
 
     $attached_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
       $phid,
       PhabricatorObjectHasFileEdgeType::EDGECONST);
     if (!$attached_phids) {
       return;
     }
 
     $omnipotent_viewer = PhabricatorUser::getOmnipotentUser();
 
     $files = id(new PhabricatorFileQuery())
       ->setViewer($omnipotent_viewer)
       ->withPHIDs($attached_phids)
       ->execute();
     foreach ($files as $file) {
       $view_policy = $file->getViewPolicy();
       if ($this->shouldScramblePolicy($view_policy)) {
         $file->scrambleSecret();
         $file->save();
       }
     }
   }
 
 
   /**
    * Check if a policy is strong enough to justify scrambling. Objects which
    * are set to very open policies don't need to scramble their files, and
    * files with very open policies don't need to be scrambled when associated
    * objects change.
    */
   private function shouldScramblePolicy($policy) {
     switch ($policy) {
       case PhabricatorPolicies::POLICY_PUBLIC:
       case PhabricatorPolicies::POLICY_USER:
         return false;
     }
 
     return true;
   }
 
   private function updateWorkboardColumns($object, $const, $old, $new) {
     // If an object is removed from a project, remove it from any proxy
     // columns for that project. This allows a task which is moved up from a
     // milestone to the parent to move back into the "Backlog" column on the
     // parent workboard.
 
     if ($const != PhabricatorProjectObjectHasProjectEdgeType::EDGECONST) {
       return;
     }
 
     // TODO: This should likely be some future WorkboardInterface.
     $appears_on_workboards = ($object instanceof ManiphestTask);
     if (!$appears_on_workboards) {
       return;
     }
 
     $removed_phids = array_keys(array_diff_key($old, $new));
     if (!$removed_phids) {
       return;
     }
 
     // Find any proxy columns for the removed projects.
     $proxy_columns = id(new PhabricatorProjectColumnQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withProxyPHIDs($removed_phids)
       ->execute();
     if (!$proxy_columns) {
       return array();
     }
 
     $proxy_phids = mpull($proxy_columns, 'getPHID');
 
     $position_table = new PhabricatorProjectColumnPosition();
     $conn_w = $position_table->establishConnection('w');
 
     queryfx(
       $conn_w,
       'DELETE FROM %T WHERE objectPHID = %s AND columnPHID IN (%Ls)',
       $position_table->getTableName(),
       $object->getPHID(),
       $proxy_phids);
   }
 
   private function getModularTransactionTypes() {
     if ($this->modularTypes === null) {
       $template = $this->object->getApplicationTransactionTemplate();
       if ($template instanceof PhabricatorModularTransaction) {
         $xtypes = $template->newModularTransactionTypes();
         foreach ($xtypes as $key => $xtype) {
           $xtype = clone $xtype;
           $xtype->setEditor($this);
           $xtypes[$key] = $xtype;
         }
       } else {
         $xtypes = array();
       }
 
       $this->modularTypes = $xtypes;
     }
 
     return $this->modularTypes;
   }
 
   private function getModularTransactionType($type) {
     $types = $this->getModularTransactionTypes();
     return idx($types, $type);
   }
 
   private function willApplyTransactions($object, array $xactions) {
     foreach ($xactions as $xaction) {
       $type = $xaction->getTransactionType();
 
       $xtype = $this->getModularTransactionType($type);
       if (!$xtype) {
         continue;
       }
 
       $xtype->willApplyTransactions($object, $xactions);
     }
   }
 
   public function getCreateObjectTitle($author, $object) {
     return pht('%s created this object.', $author);
   }
 
   public function getCreateObjectTitleForFeed($author, $object) {
     return pht('%s created an object: %s.', $author, $object);
   }
 
 /* -(  Queue  )-------------------------------------------------------------- */
 
   protected function queueTransaction(
     PhabricatorApplicationTransaction $xaction) {
     $this->transactionQueue[] = $xaction;
     return $this;
   }
 
   private function flushTransactionQueue($object) {
     if (!$this->transactionQueue) {
       return;
     }
 
     $xactions = $this->transactionQueue;
     $this->transactionQueue = array();
 
     $editor = $this->newQueueEditor();
 
     return $editor->applyTransactions($object, $xactions);
   }
 
   private function newQueueEditor() {
     $editor = id(newv(get_class($this), array()))
       ->setActor($this->getActor())
       ->setContentSource($this->getContentSource())
       ->setContinueOnNoEffect($this->getContinueOnNoEffect())
       ->setContinueOnMissingFields($this->getContinueOnMissingFields())
       ->setIsSilent($this->getIsSilent());
 
     if ($this->actingAsPHID !== null) {
       $editor->setActingAsPHID($this->actingAsPHID);
     }
 
     return $editor;
   }
 
 
 /* -(  Stamps  )------------------------------------------------------------- */
 
 
   public function newMailStampTemplates($object) {
     $actor = $this->getActor();
 
     $templates = array();
 
     $extensions = $this->newMailExtensions($object);
     foreach ($extensions as $extension) {
       $stamps = $extension->newMailStampTemplates($object);
       foreach ($stamps as $stamp) {
         $key = $stamp->getKey();
         if (isset($templates[$key])) {
           throw new Exception(
             pht(
               'Mail extension ("%s") defines a stamp template with the '.
               'same key ("%s") as another template. Each stamp template '.
               'must have a unique key.',
               get_class($extension),
               $key));
         }
 
         $stamp->setViewer($actor);
 
         $templates[$key] = $stamp;
       }
     }
 
     return $templates;
   }
 
   final public function getMailStamp($key) {
     if (!isset($this->stampTemplates)) {
       throw new PhutilInvalidStateException('newMailStampTemplates');
     }
 
     if (!isset($this->stampTemplates[$key])) {
       throw new Exception(
         pht(
           'Editor ("%s") has no mail stamp template with provided key ("%s").',
           get_class($this),
           $key));
     }
 
     return $this->stampTemplates[$key];
   }
 
   private function newMailStamps($object, array $xactions) {
     $actor = $this->getActor();
 
     $this->stampTemplates = $this->newMailStampTemplates($object);
 
     $extensions = $this->newMailExtensions($object);
     $stamps = array();
     foreach ($extensions as $extension) {
       $extension->newMailStamps($object, $xactions);
     }
 
     return $this->stampTemplates;
   }
 
   private function newMailExtensions($object) {
     $actor = $this->getActor();
 
     $all_extensions = PhabricatorMailEngineExtension::getAllExtensions();
 
     $extensions = array();
     foreach ($all_extensions as $key => $template) {
       $extension = id(clone $template)
         ->setViewer($actor)
         ->setEditor($this);
 
       if ($extension->supportsObject($object)) {
         $extensions[$key] = $extension;
       }
     }
 
     return $extensions;
   }
 
   private function generateMailStamps($object, $data) {
     if (!$data || !is_array($data)) {
       return null;
     }
 
     $templates = $this->newMailStampTemplates($object);
     foreach ($data as $spec) {
       if (!is_array($spec)) {
         continue;
       }
 
       $key = idx($spec, 'key');
       if (!isset($templates[$key])) {
         continue;
       }
 
       $type = idx($spec, 'type');
       if ($templates[$key]->getStampType() !== $type) {
         continue;
       }
 
       $value = idx($spec, 'value');
       $templates[$key]->setValueFromDictionary($value);
     }
 
     $results = array();
     foreach ($templates as $template) {
       $value = $template->getValueForRendering();
 
       $rendered = $template->renderStamps($value);
       if ($rendered === null) {
         continue;
       }
 
       $rendered = (array)$rendered;
       foreach ($rendered as $stamp) {
         $results[] = $stamp;
       }
     }
 
     natcasesort($results);
 
     return $results;
   }
 
   public function getRemovedRecipientPHIDs() {
     return $this->mailRemovedPHIDs;
   }
 
   private function buildOldRecipientLists($object, $xactions) {
     // See T4776. Before we start making any changes, build a list of the old
     // recipients. If a change removes a user from the recipient list for an
     // object we still want to notify the user about that change. This allows
     // them to respond if they didn't want to be removed.
 
     if (!$this->shouldSendMail($object, $xactions)) {
       return;
     }
 
     $this->oldTo = $this->getMailTo($object);
     $this->oldCC = $this->getMailCC($object);
 
     return $this;
   }
 
   private function applyOldRecipientLists() {
     $actor_phid = $this->getActingAsPHID();
 
     // If you took yourself off the recipient list (for example, by
     // unsubscribing or resigning) assume that you know what you did and
     // don't need to be notified.
 
     // If you just moved from "To" to "Cc" (or vice versa), you're still a
     // recipient so we don't need to add you back in.
 
     $map = array_fuse($this->mailToPHIDs) + array_fuse($this->mailCCPHIDs);
 
     foreach ($this->oldTo as $phid) {
       if ($phid === $actor_phid) {
         continue;
       }
 
       if (isset($map[$phid])) {
         continue;
       }
 
       $this->mailToPHIDs[] = $phid;
       $this->mailRemovedPHIDs[] = $phid;
     }
 
     foreach ($this->oldCC as $phid) {
       if ($phid === $actor_phid) {
         continue;
       }
 
       if (isset($map[$phid])) {
         continue;
       }
 
       $this->mailCCPHIDs[] = $phid;
       $this->mailRemovedPHIDs[] = $phid;
     }
 
     return $this;
   }
 
 }