diff --git a/src/applications/differential/engine/DifferentialChangesetEngine.php b/src/applications/differential/engine/DifferentialChangesetEngine.php
index e8a55a1b0e..d72db025ad 100644
--- a/src/applications/differential/engine/DifferentialChangesetEngine.php
+++ b/src/applications/differential/engine/DifferentialChangesetEngine.php
@@ -1,248 +1,262 @@
 <?php
 
 final class DifferentialChangesetEngine extends Phobject {
 
   public function rebuildChangesets(array $changesets) {
     assert_instances_of($changesets, 'DifferentialChangeset');
 
     foreach ($changesets as $changeset) {
       $this->detectGeneratedCode($changeset);
       $this->computeHashes($changeset);
     }
 
     $this->detectCopiedCode($changesets);
   }
 
 
 /* -(  Generated Code  )----------------------------------------------------- */
 
 
   private function detectGeneratedCode(DifferentialChangeset $changeset) {
     $is_generated_trusted = $this->isTrustedGeneratedCode($changeset);
     if ($is_generated_trusted) {
       $changeset->setTrustedChangesetAttribute(
         DifferentialChangeset::ATTRIBUTE_GENERATED,
         $is_generated_trusted);
     }
 
     $is_generated_untrusted = $this->isUntrustedGeneratedCode($changeset);
     if ($is_generated_untrusted) {
       $changeset->setUntrustedChangesetAttribute(
         DifferentialChangeset::ATTRIBUTE_GENERATED,
         $is_generated_untrusted);
     }
   }
 
   private function isTrustedGeneratedCode(DifferentialChangeset $changeset) {
 
     $filename = $changeset->getFilename();
 
     $paths = PhabricatorEnv::getEnvConfig('differential.generated-paths');
     foreach ($paths as $regexp) {
       if (preg_match($regexp, $filename)) {
         return true;
       }
     }
 
     return false;
   }
 
   private function isUntrustedGeneratedCode(DifferentialChangeset $changeset) {
 
     if ($changeset->getHunks()) {
       $new_data = $changeset->makeNewFile();
       if (strpos($new_data, '@'.'generated') !== false) {
         return true;
       }
     }
 
     return false;
   }
 
 
 /* -(  Content Hashes  )----------------------------------------------------- */
 
 
   private function computeHashes(DifferentialChangeset $changeset) {
 
     $effect_key = DifferentialChangeset::METADATA_EFFECT_HASH;
 
     $effect_hash = $this->newEffectHash($changeset);
     if ($effect_hash !== null) {
       $changeset->setChangesetMetadata($effect_key, $effect_hash);
     }
   }
 
   private function newEffectHash(DifferentialChangeset $changeset) {
 
     if ($changeset->getHunks()) {
       $new_data = $changeset->makeNewFile();
       return PhabricatorHash::digestForIndex($new_data);
     }
 
     return null;
   }
 
 
 /* -(  Copied Code  )-------------------------------------------------------- */
 
 
   private function detectCopiedCode(array $changesets) {
+    // See PHI944. If the total number of changed lines is excessively large,
+    // don't bother with copied code detection. This can take a lot of time and
+    // memory and it's not generally of any use for very large changes.
+    $max_size = 65535;
+
+    $total_size = 0;
+    foreach ($changesets as $changeset) {
+      $total_size += ($changeset->getAddLines() + $changeset->getDelLines());
+    }
+
+    if ($total_size > $max_size) {
+      return;
+    }
+
     $min_width = 30;
     $min_lines = 3;
 
     $map = array();
     $files = array();
     $types = array();
     foreach ($changesets as $changeset) {
       $file = $changeset->getFilename();
       foreach ($changeset->getHunks() as $hunk) {
         $lines = $hunk->getStructuredOldFile();
         foreach ($lines as $line => $info) {
           $type = $info['type'];
           if ($type == '\\') {
             continue;
           }
           $types[$file][$line] = $type;
 
           $text = $info['text'];
           $text = trim($text);
           $files[$file][$line] = $text;
 
           if (strlen($text) >= $min_width) {
             $map[$text][] = array($file, $line);
           }
         }
       }
     }
 
     foreach ($changesets as $changeset) {
       $copies = array();
       foreach ($changeset->getHunks() as $hunk) {
         $added = $hunk->getStructuredNewFile();
         $atype = array();
 
         foreach ($added as $line => $info) {
           $atype[$line] = $info['type'];
           $added[$line] = trim($info['text']);
         }
 
         $skip_lines = 0;
         foreach ($added as $line => $code) {
           if ($skip_lines) {
             // We're skipping lines that we already processed because we
             // extended a block above them downward to include them.
             $skip_lines--;
             continue;
           }
 
           if ($atype[$line] !== '+') {
             // This line hasn't been changed in the new file, so don't try
             // to figure out where it came from.
             continue;
           }
 
           if (empty($map[$code])) {
             // This line was too short to trigger copy/move detection.
             continue;
           }
 
           if (count($map[$code]) > 16) {
             // If there are a large number of identical lines in this diff,
             // don't try to figure out where this block came from: the analysis
             // is O(N^2), since we need to compare every line against every
             // other line. Even if we arrive at a result, it is unlikely to be
             // meaningful. See T5041.
             continue;
           }
 
           $best_length = 0;
 
           // Explore all candidates.
           foreach ($map[$code] as $val) {
             list($file, $orig_line) = $val;
             $length = 1;
 
             // Search backward and forward to find all of the adjacent lines
             // which match.
             foreach (array(-1, 1) as $direction) {
               $offset = $direction;
               while (true) {
                 if (isset($copies[$line + $offset])) {
                   // If we run into a block above us which we've already
                   // attributed to a move or copy from elsewhere, stop
                   // looking.
                   break;
                 }
 
                 if (!isset($added[$line + $offset])) {
                   // If we've run off the beginning or end of the new file,
                   // stop looking.
                   break;
                 }
 
                 if (!isset($files[$file][$orig_line + $offset])) {
                   // If we've run off the beginning or end of the original
                   // file, we also stop looking.
                   break;
                 }
 
                 $old = $files[$file][$orig_line + $offset];
                 $new = $added[$line + $offset];
                 if ($old !== $new) {
                   // If the old line doesn't match the new line, stop
                   // looking.
                   break;
                 }
 
                 $length++;
                 $offset += $direction;
               }
             }
 
             if ($length < $best_length) {
               // If we already know of a better source (more matching lines)
               // for this move/copy, stick with that one. We prefer long
               // copies/moves which match a lot of context over short ones.
               continue;
             }
 
             if ($length == $best_length) {
               if (idx($types[$file], $orig_line) != '-') {
                 // If we already know of an equally good source (same number
                 // of matching lines) and this isn't a move, stick with the
                 // other one. We prefer moves over copies.
                 continue;
               }
             }
 
             $best_length = $length;
             // ($offset - 1) contains number of forward matching lines.
             $best_offset = $offset - 1;
             $best_file = $file;
             $best_line = $orig_line;
           }
 
           $file = ($best_file == $changeset->getFilename() ? '' : $best_file);
           for ($i = $best_length; $i--; ) {
             $type = idx($types[$best_file], $best_line + $best_offset - $i);
             $copies[$line + $best_offset - $i] = ($best_length < $min_lines
               ? array() // Ignore short blocks.
               : array($file, $best_line + $best_offset - $i, $type));
           }
 
           $skip_lines = $best_offset;
         }
       }
 
       $copies = array_filter($copies);
       if ($copies) {
         $metadata = $changeset->getMetadata();
         $metadata['copy:lines'] = $copies;
         $changeset->setMetadata($metadata);
       }
     }
 
   }
 
 }
diff --git a/src/applications/diffusion/protocol/DiffusionRepositoryClusterEngine.php b/src/applications/diffusion/protocol/DiffusionRepositoryClusterEngine.php
index f85c7862fe..2e5d4215db 100644
--- a/src/applications/diffusion/protocol/DiffusionRepositoryClusterEngine.php
+++ b/src/applications/diffusion/protocol/DiffusionRepositoryClusterEngine.php
@@ -1,826 +1,829 @@
 <?php
 
 /**
  * Manages repository synchronization for cluster repositories.
  *
  * @task config Configuring Synchronization
  * @task sync Cluster Synchronization
  * @task internal Internals
  */
 final class DiffusionRepositoryClusterEngine extends Phobject {
 
   private $repository;
   private $viewer;
   private $logger;
 
   private $clusterWriteLock;
   private $clusterWriteVersion;
   private $clusterWriteOwner;
 
 
 /* -(  Configuring Synchronization  )---------------------------------------- */
 
 
   public function setRepository(PhabricatorRepository $repository) {
     $this->repository = $repository;
     return $this;
   }
 
   public function getRepository() {
     return $this->repository;
   }
 
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
   }
 
   public function getViewer() {
     return $this->viewer;
   }
 
   public function setLog(DiffusionRepositoryClusterEngineLogInterface $log) {
     $this->logger = $log;
     return $this;
   }
 
 
 /* -(  Cluster Synchronization  )-------------------------------------------- */
 
 
   /**
    * Synchronize repository version information after creating a repository.
    *
    * This initializes working copy versions for all currently bound devices to
    * 0, so that we don't get stuck making an ambiguous choice about which
    * devices are leaders when we later synchronize before a read.
    *
    * @task sync
    */
   public function synchronizeWorkingCopyAfterCreation() {
     if (!$this->shouldEnableSynchronization(false)) {
       return;
     }
 
     $repository = $this->getRepository();
     $repository_phid = $repository->getPHID();
 
     $service = $repository->loadAlmanacService();
     if (!$service) {
       throw new Exception(pht('Failed to load repository cluster service.'));
     }
 
     $bindings = $service->getActiveBindings();
     foreach ($bindings as $binding) {
       PhabricatorRepositoryWorkingCopyVersion::updateVersion(
         $repository_phid,
         $binding->getDevicePHID(),
         0);
     }
 
     return $this;
   }
 
 
   /**
    * @task sync
    */
   public function synchronizeWorkingCopyAfterHostingChange() {
     if (!$this->shouldEnableSynchronization(false)) {
       return;
     }
 
     $repository = $this->getRepository();
     $repository_phid = $repository->getPHID();
 
     $versions = PhabricatorRepositoryWorkingCopyVersion::loadVersions(
       $repository_phid);
     $versions = mpull($versions, null, 'getDevicePHID');
 
     // After converting a hosted repository to observed, or vice versa, we
     // need to reset version numbers because the clocks for observed and hosted
     // repositories run on different units.
 
     // We identify all the cluster leaders and reset their version to 0.
     // We identify all the cluster followers and demote them.
 
     // This allows the cluster to start over again at version 0 but keep the
     // same leaders.
 
     if ($versions) {
       $max_version = (int)max(mpull($versions, 'getRepositoryVersion'));
       foreach ($versions as $version) {
         $device_phid = $version->getDevicePHID();
 
         if ($version->getRepositoryVersion() == $max_version) {
           PhabricatorRepositoryWorkingCopyVersion::updateVersion(
             $repository_phid,
             $device_phid,
             0);
         } else {
           PhabricatorRepositoryWorkingCopyVersion::demoteDevice(
             $repository_phid,
             $device_phid);
         }
       }
     }
 
     return $this;
   }
 
 
   /**
    * @task sync
    */
   public function synchronizeWorkingCopyBeforeRead() {
     if (!$this->shouldEnableSynchronization(true)) {
       return;
     }
 
     $repository = $this->getRepository();
     $repository_phid = $repository->getPHID();
 
     $device = AlmanacKeys::getLiveDevice();
     $device_phid = $device->getPHID();
 
     $read_lock = PhabricatorRepositoryWorkingCopyVersion::getReadLock(
       $repository_phid,
       $device_phid);
 
     $lock_wait = phutil_units('2 minutes in seconds');
 
     $this->logLine(
       pht(
         'Acquiring read lock for repository "%s" on device "%s"...',
         $repository->getDisplayName(),
         $device->getName()));
 
     try {
       $start = PhabricatorTime::getNow();
       $read_lock->lock($lock_wait);
       $waited = (PhabricatorTime::getNow() - $start);
 
       if ($waited) {
         $this->logLine(
           pht(
             'Acquired read lock after %s second(s).',
             new PhutilNumber($waited)));
       } else {
         $this->logLine(
           pht(
             'Acquired read lock immediately.'));
       }
     } catch (PhutilLockException $ex) {
       throw new PhutilProxyException(
         pht(
           'Failed to acquire read lock after waiting %s second(s). You '.
           'may be able to retry later. (%s)',
           new PhutilNumber($lock_wait),
           $ex->getHint()),
         $ex);
     }
 
     $versions = PhabricatorRepositoryWorkingCopyVersion::loadVersions(
       $repository_phid);
     $versions = mpull($versions, null, 'getDevicePHID');
 
     $this_version = idx($versions, $device_phid);
     if ($this_version) {
       $this_version = (int)$this_version->getRepositoryVersion();
     } else {
       $this_version = -1;
     }
 
     if ($versions) {
       // This is the normal case, where we have some version information and
       // can identify which nodes are leaders. If the current node is not a
       // leader, we want to fetch from a leader and then update our version.
 
       $max_version = (int)max(mpull($versions, 'getRepositoryVersion'));
       if ($max_version > $this_version) {
         if ($repository->isHosted()) {
           $fetchable = array();
           foreach ($versions as $version) {
             if ($version->getRepositoryVersion() == $max_version) {
               $fetchable[] = $version->getDevicePHID();
             }
           }
 
           $this->synchronizeWorkingCopyFromDevices($fetchable);
         } else {
           $this->synchronizeWorkingCopyFromRemote();
         }
 
         PhabricatorRepositoryWorkingCopyVersion::updateVersion(
           $repository_phid,
           $device_phid,
           $max_version);
       } else {
         $this->logLine(
           pht(
             'Device "%s" is already a cluster leader and does not need '.
             'to be synchronized.',
             $device->getName()));
       }
 
       $result_version = $max_version;
     } else {
       // If no version records exist yet, we need to be careful, because we
       // can not tell which nodes are leaders.
 
       // There might be several nodes with arbitrary existing data, and we have
       // no way to tell which one has the "right" data. If we pick wrong, we
       // might erase some or all of the data in the repository.
 
       // Since this is dangerous, we refuse to guess unless there is only one
       // device. If we're the only device in the group, we obviously must be
       // a leader.
 
       $service = $repository->loadAlmanacService();
       if (!$service) {
         throw new Exception(pht('Failed to load repository cluster service.'));
       }
 
       $bindings = $service->getActiveBindings();
       $device_map = array();
       foreach ($bindings as $binding) {
         $device_map[$binding->getDevicePHID()] = true;
       }
 
       if (count($device_map) > 1) {
         throw new Exception(
           pht(
             'Repository "%s" exists on more than one device, but no device '.
             'has any repository version information. Phabricator can not '.
             'guess which copy of the existing data is authoritative. Promote '.
             'a device or see "Ambiguous Leaders" in the documentation.',
             $repository->getDisplayName()));
       }
 
       if (empty($device_map[$device->getPHID()])) {
         throw new Exception(
           pht(
             'Repository "%s" is being synchronized on device "%s", but '.
             'this device is not bound to the corresponding cluster '.
             'service ("%s").',
             $repository->getDisplayName(),
             $device->getName(),
             $service->getName()));
       }
 
       // The current device is the only device in service, so it must be a
       // leader. We can safely have any future nodes which come online read
       // from it.
       PhabricatorRepositoryWorkingCopyVersion::updateVersion(
         $repository_phid,
         $device_phid,
         0);
 
       $result_version = 0;
     }
 
     $read_lock->unlock();
 
     return $result_version;
   }
 
 
   /**
    * @task sync
    */
   public function synchronizeWorkingCopyBeforeWrite() {
     if (!$this->shouldEnableSynchronization(true)) {
       return;
     }
 
     $repository = $this->getRepository();
     $viewer = $this->getViewer();
 
     $repository_phid = $repository->getPHID();
 
     $device = AlmanacKeys::getLiveDevice();
     $device_phid = $device->getPHID();
 
     $table = new PhabricatorRepositoryWorkingCopyVersion();
     $locked_connection = $table->establishConnection('w');
 
     $write_lock = PhabricatorRepositoryWorkingCopyVersion::getWriteLock(
       $repository_phid);
 
     $write_lock->useSpecificConnection($locked_connection);
 
     $this->logLine(
       pht(
         'Acquiring write lock for repository "%s"...',
         $repository->getDisplayName()));
 
     $lock_wait = phutil_units('2 minutes in seconds');
     try {
       $write_wait_start = microtime(true);
 
       $start = PhabricatorTime::getNow();
       $step_wait = 1;
 
       while (true) {
         try {
           $write_lock->lock((int)floor($step_wait));
           $write_wait_end = microtime(true);
           break;
         } catch (PhutilLockException $ex) {
           $waited = (PhabricatorTime::getNow() - $start);
           if ($waited > $lock_wait) {
             throw $ex;
           }
           $this->logActiveWriter($viewer, $repository);
         }
 
         // Wait a little longer before the next message we print.
         $step_wait = $step_wait + 0.5;
         $step_wait = min($step_wait, 3);
       }
 
       $waited = (PhabricatorTime::getNow() - $start);
       if ($waited) {
         $this->logLine(
           pht(
             'Acquired write lock after %s second(s).',
             new PhutilNumber($waited)));
       } else {
         $this->logLine(
           pht(
             'Acquired write lock immediately.'));
       }
     } catch (PhutilLockException $ex) {
       throw new PhutilProxyException(
         pht(
           'Failed to acquire write lock after waiting %s second(s). You '.
           'may be able to retry later. (%s)',
           new PhutilNumber($lock_wait),
           $ex->getHint()),
         $ex);
     }
 
     $versions = PhabricatorRepositoryWorkingCopyVersion::loadVersions(
       $repository_phid);
     foreach ($versions as $version) {
       if (!$version->getIsWriting()) {
         continue;
       }
 
       throw new Exception(
         pht(
           'An previous write to this repository was interrupted; refusing '.
           'new writes. This issue requires operator intervention to resolve, '.
           'see "Write Interruptions" in the "Cluster: Repositories" in the '.
           'documentation for instructions.'));
     }
 
     $read_wait_start = microtime(true);
     try {
       $max_version = $this->synchronizeWorkingCopyBeforeRead();
     } catch (Exception $ex) {
       $write_lock->unlock();
       throw $ex;
     }
     $read_wait_end = microtime(true);
 
     $pid = getmypid();
     $hash = Filesystem::readRandomCharacters(12);
     $this->clusterWriteOwner = "{$pid}.{$hash}";
 
     PhabricatorRepositoryWorkingCopyVersion::willWrite(
       $locked_connection,
       $repository_phid,
       $device_phid,
       array(
         'userPHID' => $viewer->getPHID(),
         'epoch' => PhabricatorTime::getNow(),
         'devicePHID' => $device_phid,
       ),
       $this->clusterWriteOwner);
 
     $this->clusterWriteVersion = $max_version;
     $this->clusterWriteLock = $write_lock;
 
     $write_wait = ($write_wait_end - $write_wait_start);
     $read_wait = ($read_wait_end - $read_wait_start);
 
     $log = $this->logger;
     if ($log) {
       $log->writeClusterEngineLogProperty('readWait', $read_wait);
       $log->writeClusterEngineLogProperty('writeWait', $write_wait);
     }
   }
 
 
   public function synchronizeWorkingCopyAfterDiscovery($new_version) {
     if (!$this->shouldEnableSynchronization(true)) {
       return;
     }
 
     $repository = $this->getRepository();
     $repository_phid = $repository->getPHID();
     if ($repository->isHosted()) {
       return;
     }
 
     $viewer = $this->getViewer();
 
     $device = AlmanacKeys::getLiveDevice();
     $device_phid = $device->getPHID();
 
     // NOTE: We are not holding a lock here because this method is only called
     // from PhabricatorRepositoryDiscoveryEngine, which already holds a device
     // lock. Even if we do race here and record an older version, the
     // consequences are mild: we only do extra work to correct it later.
 
     $versions = PhabricatorRepositoryWorkingCopyVersion::loadVersions(
       $repository_phid);
     $versions = mpull($versions, null, 'getDevicePHID');
 
     $this_version = idx($versions, $device_phid);
     if ($this_version) {
       $this_version = (int)$this_version->getRepositoryVersion();
     } else {
       $this_version = -1;
     }
 
     if ($new_version > $this_version) {
       PhabricatorRepositoryWorkingCopyVersion::updateVersion(
         $repository_phid,
         $device_phid,
         $new_version);
     }
   }
 
 
   /**
    * @task sync
    */
   public function synchronizeWorkingCopyAfterWrite() {
     if (!$this->shouldEnableSynchronization(true)) {
       return;
     }
 
     if (!$this->clusterWriteLock) {
       throw new Exception(
         pht(
           'Trying to synchronize after write, but not holding a write '.
           'lock!'));
     }
 
     $repository = $this->getRepository();
     $repository_phid = $repository->getPHID();
 
     $device = AlmanacKeys::getLiveDevice();
     $device_phid = $device->getPHID();
 
     // It is possible that we've lost the global lock while receiving the push.
     // For example, the master database may have been restarted between the
     // time we acquired the global lock and now, when the push has finished.
 
     // We wrote a durable lock while we were holding the the global lock,
     // essentially upgrading our lock. We can still safely release this upgraded
     // lock even if we're no longer holding the global lock.
 
     // If we fail to release the lock, the repository will be frozen until
     // an operator can figure out what happened, so we try pretty hard to
     // reconnect to the database and release the lock.
 
     $now = PhabricatorTime::getNow();
     $duration = phutil_units('5 minutes in seconds');
     $try_until = $now + $duration;
 
     $did_release = false;
     $already_failed = false;
     while (PhabricatorTime::getNow() <= $try_until) {
       try {
         // NOTE: This means we're still bumping the version when pushes fail. We
         // could select only un-rejected events instead to bump a little less
         // often.
 
         $new_log = id(new PhabricatorRepositoryPushEventQuery())
           ->setViewer(PhabricatorUser::getOmnipotentUser())
           ->withRepositoryPHIDs(array($repository_phid))
           ->setLimit(1)
           ->executeOne();
 
         $old_version = $this->clusterWriteVersion;
         if ($new_log) {
           $new_version = $new_log->getID();
         } else {
           $new_version = $old_version;
         }
 
         PhabricatorRepositoryWorkingCopyVersion::didWrite(
           $repository_phid,
           $device_phid,
           $this->clusterWriteVersion,
           $new_version,
           $this->clusterWriteOwner);
         $did_release = true;
         break;
       } catch (AphrontConnectionQueryException $ex) {
         $connection_exception = $ex;
       } catch (AphrontConnectionLostQueryException $ex) {
         $connection_exception = $ex;
       }
 
       if (!$already_failed) {
         $already_failed = true;
         $this->logLine(
           pht('CRITICAL. Failed to release cluster write lock!'));
 
         $this->logLine(
           pht(
             'The connection to the master database was lost while receiving '.
             'the write.'));
 
         $this->logLine(
           pht(
             'This process will spend %s more second(s) attempting to '.
             'recover, then give up.',
             new PhutilNumber($duration)));
       }
 
       sleep(1);
     }
 
     if ($did_release) {
       if ($already_failed) {
         $this->logLine(
           pht('RECOVERED. Link to master database was restored.'));
       }
       $this->logLine(pht('Released cluster write lock.'));
     } else {
       throw new Exception(
         pht(
           'Failed to reconnect to master database and release held write '.
           'lock ("%s") on device "%s" for repository "%s" after trying '.
           'for %s seconds(s). This repository will be frozen.',
           $this->clusterWriteOwner,
           $device->getName(),
           $this->getDisplayName(),
           new PhutilNumber($duration)));
     }
 
     // We can continue even if we've lost this lock, everything is still
     // consistent.
     try {
       $this->clusterWriteLock->unlock();
     } catch (Exception $ex) {
       // Ignore.
     }
 
     $this->clusterWriteLock = null;
     $this->clusterWriteOwner = null;
   }
 
 
 /* -(  Internals  )---------------------------------------------------------- */
 
 
   /**
    * @task internal
    */
   private function shouldEnableSynchronization($require_device) {
     $repository = $this->getRepository();
 
     $service_phid = $repository->getAlmanacServicePHID();
     if (!$service_phid) {
       return false;
     }
 
     if (!$repository->supportsSynchronization()) {
       return false;
     }
 
     if ($require_device) {
       $device = AlmanacKeys::getLiveDevice();
       if (!$device) {
         return false;
       }
     }
 
     return true;
   }
 
 
   /**
    * @task internal
    */
   private function synchronizeWorkingCopyFromRemote() {
     $repository = $this->getRepository();
     $device = AlmanacKeys::getLiveDevice();
 
     $local_path = $repository->getLocalPath();
     $fetch_uri = $repository->getRemoteURIEnvelope();
 
     if ($repository->isGit()) {
       $this->requireWorkingCopy();
 
       $argv = array(
         'fetch --prune -- %P %s',
         $fetch_uri,
         '+refs/*:refs/*',
       );
     } else {
       throw new Exception(pht('Remote sync only supported for git!'));
     }
 
     $future = DiffusionCommandEngine::newCommandEngine($repository)
       ->setArgv($argv)
       ->setSudoAsDaemon(true)
       ->setCredentialPHID($repository->getCredentialPHID())
       ->setURI($repository->getRemoteURIObject())
       ->newFuture();
 
     $future->setCWD($local_path);
 
     try {
       $future->resolvex();
     } catch (Exception $ex) {
       $this->logLine(
         pht(
           'Synchronization of "%s" from remote failed: %s',
           $device->getName(),
           $ex->getMessage()));
       throw $ex;
     }
   }
 
 
   /**
    * @task internal
    */
   private function synchronizeWorkingCopyFromDevices(array $device_phids) {
     $repository = $this->getRepository();
 
     $service = $repository->loadAlmanacService();
     if (!$service) {
       throw new Exception(pht('Failed to load repository cluster service.'));
     }
 
     $device_map = array_fuse($device_phids);
     $bindings = $service->getActiveBindings();
 
     $fetchable = array();
     foreach ($bindings as $binding) {
       // We can't fetch from nodes which don't have the newest version.
       $device_phid = $binding->getDevicePHID();
       if (empty($device_map[$device_phid])) {
         continue;
       }
 
       // TODO: For now, only fetch over SSH. We could support fetching over
       // HTTP eventually.
       if ($binding->getAlmanacPropertyValue('protocol') != 'ssh') {
         continue;
       }
 
       $fetchable[] = $binding;
     }
 
     if (!$fetchable) {
       throw new Exception(
         pht(
           'Leader lost: no up-to-date nodes in repository cluster are '.
           'fetchable.'));
     }
 
+    // If we can synchronize from multiple sources, choose one at random.
+    shuffle($fetchable);
+
     $caught = null;
     foreach ($fetchable as $binding) {
       try {
         $this->synchronizeWorkingCopyFromBinding($binding);
         $caught = null;
         break;
       } catch (Exception $ex) {
         $caught = $ex;
       }
     }
 
     if ($caught) {
       throw $caught;
     }
   }
 
 
   /**
    * @task internal
    */
   private function synchronizeWorkingCopyFromBinding($binding) {
     $repository = $this->getRepository();
     $device = AlmanacKeys::getLiveDevice();
 
     $this->logLine(
       pht(
         'Synchronizing this device ("%s") from cluster leader ("%s") before '.
         'read.',
         $device->getName(),
         $binding->getDevice()->getName()));
 
     $fetch_uri = $repository->getClusterRepositoryURIFromBinding($binding);
     $local_path = $repository->getLocalPath();
 
     if ($repository->isGit()) {
       $this->requireWorkingCopy();
 
       $argv = array(
         'fetch --prune -- %s %s',
         $fetch_uri,
         '+refs/*:refs/*',
       );
     } else {
       throw new Exception(pht('Binding sync only supported for git!'));
     }
 
     $future = DiffusionCommandEngine::newCommandEngine($repository)
       ->setArgv($argv)
       ->setConnectAsDevice(true)
       ->setSudoAsDaemon(true)
       ->setURI($fetch_uri)
       ->newFuture();
 
     $future->setCWD($local_path);
 
     try {
       $future->resolvex();
     } catch (Exception $ex) {
       $this->logLine(
         pht(
           'Synchronization of "%s" from leader "%s" failed: %s',
           $device->getName(),
           $binding->getDevice()->getName(),
           $ex->getMessage()));
       throw $ex;
     }
   }
 
 
   /**
    * @task internal
    */
   private function logLine($message) {
     return $this->logText("# {$message}\n");
   }
 
 
   /**
    * @task internal
    */
   private function logText($message) {
     $log = $this->logger;
     if ($log) {
       $log->writeClusterEngineLogMessage($message);
     }
     return $this;
   }
 
   private function requireWorkingCopy() {
     $repository = $this->getRepository();
     $local_path = $repository->getLocalPath();
 
     if (!Filesystem::pathExists($local_path)) {
       $device = AlmanacKeys::getLiveDevice();
 
       throw new Exception(
         pht(
           'Repository "%s" does not have a working copy on this device '.
           'yet, so it can not be synchronized. Wait for the daemons to '.
           'construct one or run `bin/repository update %s` on this host '.
           '("%s") to build it explicitly.',
           $repository->getDisplayName(),
           $repository->getMonogram(),
           $device->getName()));
     }
   }
 
   private function logActiveWriter(
     PhabricatorUser $viewer,
     PhabricatorRepository $repository) {
 
     $writer = PhabricatorRepositoryWorkingCopyVersion::loadWriter(
       $repository->getPHID());
     if (!$writer) {
       $this->logLine(pht('Waiting on another user to finish writing...'));
       return;
     }
 
     $user_phid = $writer->getWriteProperty('userPHID');
     $device_phid = $writer->getWriteProperty('devicePHID');
     $epoch = $writer->getWriteProperty('epoch');
 
     $phids = array($user_phid, $device_phid);
     $handles = $viewer->loadHandles($phids);
 
     $duration = (PhabricatorTime::getNow() - $epoch) + 1;
 
     $this->logLine(
       pht(
         'Waiting for %s to finish writing (on device "%s" for %ss)...',
         $handles[$user_phid]->getName(),
         $handles[$device_phid]->getName(),
         new PhutilNumber($duration)));
   }
 
 }
diff --git a/src/applications/metamta/typeahead/PhabricatorMetaMTAMailableFunctionDatasource.php b/src/applications/metamta/typeahead/PhabricatorMetaMTAMailableFunctionDatasource.php
index 4b231b959e..b5d82c9749 100644
--- a/src/applications/metamta/typeahead/PhabricatorMetaMTAMailableFunctionDatasource.php
+++ b/src/applications/metamta/typeahead/PhabricatorMetaMTAMailableFunctionDatasource.php
@@ -1,29 +1,30 @@
 <?php
 
 final class PhabricatorMetaMTAMailableFunctionDatasource
   extends PhabricatorTypeaheadCompositeDatasource {
 
   public function getBrowseTitle() {
     return pht('Browse Subscribers');
   }
 
   public function getPlaceholderText() {
     return pht(
       'Type a username, project, mailing list, package, or function...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorMetaMTAApplication';
   }
 
   public function getComponentDatasources() {
     return array(
       new PhabricatorViewerDatasource(),
       new PhabricatorPeopleDatasource(),
       new PhabricatorProjectMembersDatasource(),
       new PhabricatorProjectDatasource(),
       new PhabricatorOwnersPackageDatasource(),
+      new PhabricatorOwnersPackageOwnerDatasource(),
     );
   }
 
 }
diff --git a/src/applications/owners/typeahead/PhabricatorOwnersPackageOwnerDatasource.php b/src/applications/owners/typeahead/PhabricatorOwnersPackageOwnerDatasource.php
index 99e770d266..2a0b16e60f 100644
--- a/src/applications/owners/typeahead/PhabricatorOwnersPackageOwnerDatasource.php
+++ b/src/applications/owners/typeahead/PhabricatorOwnersPackageOwnerDatasource.php
@@ -1,141 +1,149 @@
 <?php
 
 final class PhabricatorOwnersPackageOwnerDatasource
   extends PhabricatorTypeaheadCompositeDatasource {
 
   public function getBrowseTitle() {
     return pht('Browse Packages by Owner');
   }
 
   public function getPlaceholderText() {
     return pht('Type packages(<user>) or packages(<project>)...');
   }
 
   public function getDatasourceApplicationClass() {
     return 'PhabricatorOwnersApplication';
   }
 
   public function getComponentDatasources() {
     return array(
       new PhabricatorPeopleDatasource(),
       new PhabricatorProjectDatasource(),
     );
   }
 
   public function getDatasourceFunctions() {
     return array(
       'packages' => array(
         'name' => pht('Packages: ...'),
         'arguments' => pht('owner'),
-        'summary' => pht("Find results in any of an owner's projects."),
+        'summary' => pht("Find results in any of an owner's packages."),
         'description' => pht(
           "This function allows you to find results associated with any ".
           "of the packages a specified user or project is an owner of. ".
           "For example, this will find results associated with all of ".
           "the projects `%s` owns:\n\n%s\n\n",
           'alincoln',
           '> packages(alincoln)'),
       ),
     );
   }
 
   protected function didLoadResults(array $results) {
     foreach ($results as $result) {
       $result
         ->setColor(null)
         ->setTokenType(PhabricatorTypeaheadTokenView::TYPE_FUNCTION)
         ->setIcon('fa-asterisk')
         ->setPHID('packages('.$result->getPHID().')')
         ->setDisplayName(pht('Packages: %s', $result->getDisplayName()))
         ->setName($result->getName().' packages');
     }
 
     return $results;
   }
 
   protected function evaluateFunction($function, array $argv_list) {
     $phids = array();
     foreach ($argv_list as $argv) {
       $phids[] = head($argv);
     }
 
     $phids = $this->resolvePHIDs($phids);
 
-    $user_phids = array();
+    $owner_phids = array();
     foreach ($phids as $key => $phid) {
-      if (phid_get_type($phid) == PhabricatorPeopleUserPHIDType::TYPECONST) {
-        $user_phids[] = $phid;
-        unset($phids[$key]);
+      switch (phid_get_type($phid)) {
+        case PhabricatorPeopleUserPHIDType::TYPECONST:
+        case PhabricatorProjectProjectPHIDType::TYPECONST:
+          $owner_phids[] = $phid;
+          unset($phids[$key]);
+          break;
       }
     }
 
-    if ($user_phids) {
+    if ($owner_phids) {
       $packages = id(new PhabricatorOwnersPackageQuery())
         ->setViewer($this->getViewer())
-        ->withOwnerPHIDs($user_phids)
+        ->withOwnerPHIDs($owner_phids)
         ->execute();
       foreach ($packages as $package) {
         $phids[] = $package->getPHID();
       }
     }
 
     return $phids;
   }
 
   public function renderFunctionTokens($function, array $argv_list) {
     $phids = array();
     foreach ($argv_list as $argv) {
       $phids[] = head($argv);
     }
 
     $phids = $this->resolvePHIDs($phids);
 
     $tokens = $this->renderTokens($phids);
     foreach ($tokens as $token) {
       $token->setColor(null);
       if ($token->isInvalid()) {
         $token
           ->setValue(pht('Packages: Invalid Owner'));
       } else {
         $token
           ->setIcon('fa-asterisk')
           ->setTokenType(PhabricatorTypeaheadTokenView::TYPE_FUNCTION)
           ->setKey('packages('.$token->getKey().')')
           ->setValue(pht('Packages: %s', $token->getValue()));
       }
     }
 
     return $tokens;
   }
 
   private function resolvePHIDs(array $phids) {
 
     // TODO: It would be nice for this to handle `packages(#project)` from a
     // query string or eventually via Conduit. This could also share code with
     // PhabricatorProjectLogicalUserDatasource.
 
     $usernames = array();
     foreach ($phids as $key => $phid) {
-      if (phid_get_type($phid) != PhabricatorPeopleUserPHIDType::TYPECONST) {
-        $usernames[$key] = $phid;
+      switch (phid_get_type($phid)) {
+        case PhabricatorPeopleUserPHIDType::TYPECONST:
+        case PhabricatorProjectProjectPHIDType::TYPECONST:
+          break;
+        default:
+          $usernames[$key] = $phid;
+          break;
       }
     }
 
     if ($usernames) {
       $users = id(new PhabricatorPeopleQuery())
         ->setViewer($this->getViewer())
         ->withUsernames($usernames)
         ->execute();
       $users = mpull($users, null, 'getUsername');
       foreach ($usernames as $key => $username) {
         $user = idx($users, $username);
         if ($user) {
           $phids[$key] = $user->getPHID();
         }
       }
     }
 
     return $phids;
   }
 
 }
diff --git a/src/applications/repository/storage/PhabricatorRepository.php b/src/applications/repository/storage/PhabricatorRepository.php
index 8889040ddf..52824c2aa4 100644
--- a/src/applications/repository/storage/PhabricatorRepository.php
+++ b/src/applications/repository/storage/PhabricatorRepository.php
@@ -1,2705 +1,2767 @@
 <?php
 
 /**
  * @task uri        Repository URI Management
  * @task autoclose  Autoclose
  * @task sync       Cluster Synchronization
  */
 final class PhabricatorRepository extends PhabricatorRepositoryDAO
   implements
     PhabricatorApplicationTransactionInterface,
     PhabricatorPolicyInterface,
     PhabricatorFlaggableInterface,
     PhabricatorMarkupInterface,
     PhabricatorDestructibleInterface,
     PhabricatorDestructibleCodexInterface,
     PhabricatorProjectInterface,
     PhabricatorSpacesInterface,
     PhabricatorConduitResultInterface,
     PhabricatorFulltextInterface,
     PhabricatorFerretInterface {
 
   /**
    * Shortest hash we'll recognize in raw "a829f32" form.
    */
   const MINIMUM_UNQUALIFIED_HASH = 7;
 
   /**
    * Shortest hash we'll recognize in qualified "rXab7ef2f8" form.
    */
   const MINIMUM_QUALIFIED_HASH = 5;
 
   /**
    * Minimum number of commits to an empty repository to trigger "import" mode.
    */
   const IMPORT_THRESHOLD = 7;
 
   const TABLE_PATH = 'repository_path';
   const TABLE_PATHCHANGE = 'repository_pathchange';
   const TABLE_FILESYSTEM = 'repository_filesystem';
   const TABLE_SUMMARY = 'repository_summary';
   const TABLE_LINTMESSAGE = 'repository_lintmessage';
   const TABLE_PARENTS = 'repository_parents';
   const TABLE_COVERAGE = 'repository_coverage';
 
   const BECAUSE_REPOSITORY_IMPORTING = 'auto/importing';
   const BECAUSE_AUTOCLOSE_DISABLED = 'auto/disabled';
   const BECAUSE_NOT_ON_AUTOCLOSE_BRANCH = 'auto/nobranch';
   const BECAUSE_BRANCH_UNTRACKED = 'auto/notrack';
   const BECAUSE_BRANCH_NOT_AUTOCLOSE = 'auto/noclose';
   const BECAUSE_AUTOCLOSE_FORCED = 'auto/forced';
 
   const STATUS_ACTIVE = 'active';
   const STATUS_INACTIVE = 'inactive';
 
   protected $name;
   protected $callsign;
   protected $repositorySlug;
   protected $uuid;
   protected $viewPolicy;
   protected $editPolicy;
   protected $pushPolicy;
   protected $profileImagePHID;
 
   protected $versionControlSystem;
   protected $details = array();
   protected $credentialPHID;
   protected $almanacServicePHID;
   protected $spacePHID;
   protected $localPath;
 
   private $commitCount = self::ATTACHABLE;
   private $mostRecentCommit = self::ATTACHABLE;
   private $projectPHIDs = self::ATTACHABLE;
   private $uris = self::ATTACHABLE;
   private $profileImageFile = self::ATTACHABLE;
 
 
   public static function initializeNewRepository(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
       ->withClasses(array('PhabricatorDiffusionApplication'))
       ->executeOne();
 
     $view_policy = $app->getPolicy(DiffusionDefaultViewCapability::CAPABILITY);
     $edit_policy = $app->getPolicy(DiffusionDefaultEditCapability::CAPABILITY);
     $push_policy = $app->getPolicy(DiffusionDefaultPushCapability::CAPABILITY);
 
     $repository = id(new PhabricatorRepository())
       ->setViewPolicy($view_policy)
       ->setEditPolicy($edit_policy)
       ->setPushPolicy($push_policy)
       ->setSpacePHID($actor->getDefaultSpacePHID());
 
     // Put the repository in "Importing" mode until we finish
     // parsing it.
     $repository->setDetail('importing', true);
 
     return $repository;
   }
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_AUX_PHID => true,
       self::CONFIG_SERIALIZATION => array(
         'details' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
         'name' => 'sort255',
         'callsign' => 'sort32?',
         'repositorySlug' => 'sort64?',
         'versionControlSystem' => 'text32',
         'uuid' => 'text64?',
         'pushPolicy' => 'policy',
         'credentialPHID' => 'phid?',
         'almanacServicePHID' => 'phid?',
         'localPath' => 'text128?',
         'profileImagePHID' => 'phid?',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'callsign' => array(
           'columns' => array('callsign'),
           'unique' => true,
         ),
         'key_name' => array(
           'columns' => array('name(128)'),
         ),
         'key_vcs' => array(
           'columns' => array('versionControlSystem'),
         ),
         'key_slug' => array(
           'columns' => array('repositorySlug'),
           'unique' => true,
         ),
         'key_local' => array(
           'columns' => array('localPath'),
           'unique' => true,
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function generatePHID() {
     return PhabricatorPHID::generateNewPHID(
       PhabricatorRepositoryRepositoryPHIDType::TYPECONST);
   }
 
   public static function getStatusMap() {
     return array(
       self::STATUS_ACTIVE => array(
         'name' => pht('Active'),
         'isTracked' => 1,
       ),
       self::STATUS_INACTIVE => array(
         'name' => pht('Inactive'),
         'isTracked' => 0,
       ),
     );
   }
 
   public static function getStatusNameMap() {
     return ipull(self::getStatusMap(), 'name');
   }
 
   public function getStatus() {
     if ($this->isTracked()) {
       return self::STATUS_ACTIVE;
     } else {
       return self::STATUS_INACTIVE;
     }
   }
 
   public function toDictionary() {
     return array(
       'id'          => $this->getID(),
       'name'        => $this->getName(),
       'phid'        => $this->getPHID(),
       'callsign'    => $this->getCallsign(),
       'monogram'    => $this->getMonogram(),
       'vcs'         => $this->getVersionControlSystem(),
       'uri'         => PhabricatorEnv::getProductionURI($this->getURI()),
       'remoteURI'   => (string)$this->getRemoteURI(),
       'description' => $this->getDetail('description'),
       'isActive'    => $this->isTracked(),
       'isHosted'    => $this->isHosted(),
       'isImporting' => $this->isImporting(),
       'encoding'    => $this->getDefaultTextEncoding(),
       'staging' => array(
         'supported' => $this->supportsStaging(),
         'prefix' => 'phabricator',
         'uri' => $this->getStagingURI(),
       ),
     );
   }
 
   public function getDefaultTextEncoding() {
     return $this->getDetail('encoding', 'UTF-8');
   }
 
   public function getMonogram() {
     $callsign = $this->getCallsign();
     if (strlen($callsign)) {
       return "r{$callsign}";
     }
 
     $id = $this->getID();
     return "R{$id}";
   }
 
   public function getDisplayName() {
     $slug = $this->getRepositorySlug();
     if (strlen($slug)) {
       return $slug;
     }
 
     return $this->getMonogram();
   }
 
   public function getAllMonograms() {
     $monograms = array();
 
     $monograms[] = 'R'.$this->getID();
 
     $callsign = $this->getCallsign();
     if (strlen($callsign)) {
       $monograms[] = 'r'.$callsign;
     }
 
     return $monograms;
   }
 
   public function setLocalPath($path) {
     // Convert any extra slashes ("//") in the path to a single slash ("/").
     $path = preg_replace('(//+)', '/', $path);
 
     return parent::setLocalPath($path);
   }
 
   public function getDetail($key, $default = null) {
     return idx($this->details, $key, $default);
   }
 
   public function getHumanReadableDetail($key, $default = null) {
     $value = $this->getDetail($key, $default);
 
     switch ($key) {
       case 'branch-filter':
       case 'close-commits-filter':
         $value = array_keys($value);
         $value = implode(', ', $value);
         break;
     }
 
     return $value;
   }
 
   public function setDetail($key, $value) {
     $this->details[$key] = $value;
     return $this;
   }
 
   public function attachCommitCount($count) {
     $this->commitCount = $count;
     return $this;
   }
 
   public function getCommitCount() {
     return $this->assertAttached($this->commitCount);
   }
 
   public function attachMostRecentCommit(
     PhabricatorRepositoryCommit $commit = null) {
     $this->mostRecentCommit = $commit;
     return $this;
   }
 
   public function getMostRecentCommit() {
     return $this->assertAttached($this->mostRecentCommit);
   }
 
   public function getDiffusionBrowseURIForPath(
     PhabricatorUser $user,
     $path,
     $line = null,
     $branch = null) {
 
     $drequest = DiffusionRequest::newFromDictionary(
       array(
         'user' => $user,
         'repository' => $this,
         'path' => $path,
         'branch' => $branch,
       ));
 
     return $drequest->generateURI(
       array(
         'action' => 'browse',
         'line'   => $line,
       ));
   }
 
   public function getSubversionBaseURI($commit = null) {
     $subpath = $this->getDetail('svn-subpath');
     if (!strlen($subpath)) {
       $subpath = null;
     }
     return $this->getSubversionPathURI($subpath, $commit);
   }
 
   public function getSubversionPathURI($path = null, $commit = null) {
     $vcs = $this->getVersionControlSystem();
     if ($vcs != PhabricatorRepositoryType::REPOSITORY_TYPE_SVN) {
       throw new Exception(pht('Not a subversion repository!'));
     }
 
     if ($this->isHosted()) {
       $uri = 'file://'.$this->getLocalPath();
     } else {
       $uri = $this->getDetail('remote-uri');
     }
 
     $uri = rtrim($uri, '/');
 
     if (strlen($path)) {
       $path = rawurlencode($path);
       $path = str_replace('%2F', '/', $path);
       $uri = $uri.'/'.ltrim($path, '/');
     }
 
     if ($path !== null || $commit !== null) {
       $uri .= '@';
     }
 
     if ($commit !== null) {
       $uri .= $commit;
     }
 
     return $uri;
   }
 
   public function attachProjectPHIDs(array $project_phids) {
     $this->projectPHIDs = $project_phids;
     return $this;
   }
 
   public function getProjectPHIDs() {
     return $this->assertAttached($this->projectPHIDs);
   }
 
 
   /**
    * Get the name of the directory this repository should clone or checkout
    * into. For example, if the repository name is "Example Repository", a
    * reasonable name might be "example-repository". This is used to help users
    * get reasonable results when cloning repositories, since they generally do
    * not want to clone into directories called "X/" or "Example Repository/".
    *
    * @return string
    */
   public function getCloneName() {
     $name = $this->getRepositorySlug();
 
     // Make some reasonable effort to produce reasonable default directory
     // names from repository names.
     if (!strlen($name)) {
       $name = $this->getName();
       $name = phutil_utf8_strtolower($name);
       $name = preg_replace('@[ -/:->]+@', '-', $name);
       $name = trim($name, '-');
       if (!strlen($name)) {
         $name = $this->getCallsign();
       }
     }
 
     return $name;
   }
 
   public static function isValidRepositorySlug($slug) {
     try {
       self::assertValidRepositorySlug($slug);
       return true;
     } catch (Exception $ex) {
       return false;
     }
   }
 
   public static function assertValidRepositorySlug($slug) {
     if (!strlen($slug)) {
       throw new Exception(
         pht(
           'The empty string is not a valid repository short name. '.
           'Repository short names must be at least one character long.'));
     }
 
     if (strlen($slug) > 64) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names must not be longer than 64 characters.',
           $slug));
     }
 
     if (preg_match('/[^a-zA-Z0-9._-]/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names may only contain letters, numbers, periods, hyphens '.
           'and underscores.',
           $slug));
     }
 
     if (!preg_match('/^[a-zA-Z0-9]/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names must begin with a letter or number.',
           $slug));
     }
 
     if (!preg_match('/[a-zA-Z0-9]\z/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names must end with a letter or number.',
           $slug));
     }
 
     if (preg_match('/__|--|\\.\\./', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names must not contain multiple consecutive underscores, '.
           'hyphens, or periods.',
           $slug));
     }
 
     if (preg_match('/^[A-Z]+\z/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names may not contain only uppercase letters.',
           $slug));
     }
 
     if (preg_match('/^\d+\z/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names may not contain only numbers.',
           $slug));
     }
 
     if (preg_match('/\\.git/', $slug)) {
       throw new Exception(
         pht(
           'The name "%s" is not a valid repository short name. Repository '.
           'short names must not end in ".git". This suffix will be added '.
           'automatically in appropriate contexts.',
           $slug));
     }
   }
 
   public static function assertValidCallsign($callsign) {
     if (!strlen($callsign)) {
       throw new Exception(
         pht(
           'A repository callsign must be at least one character long.'));
     }
 
     if (strlen($callsign) > 32) {
       throw new Exception(
         pht(
           'The callsign "%s" is not a valid repository callsign. Callsigns '.
           'must be no more than 32 bytes long.',
           $callsign));
     }
 
     if (!preg_match('/^[A-Z]+\z/', $callsign)) {
       throw new Exception(
         pht(
           'The callsign "%s" is not a valid repository callsign. Callsigns '.
           'may only contain UPPERCASE letters.',
           $callsign));
     }
   }
 
   public function getProfileImageURI() {
     return $this->getProfileImageFile()->getBestURI();
   }
 
   public function attachProfileImageFile(PhabricatorFile $file) {
     $this->profileImageFile = $file;
     return $this;
   }
 
   public function getProfileImageFile() {
     return $this->assertAttached($this->profileImageFile);
   }
 
 
 
 /* -(  Remote Command Execution  )------------------------------------------- */
 
 
   public function execRemoteCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newRemoteCommandFuture($args)->resolve();
   }
 
   public function execxRemoteCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newRemoteCommandFuture($args)->resolvex();
   }
 
   public function getRemoteCommandFuture($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newRemoteCommandFuture($args);
   }
 
   public function passthruRemoteCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newRemoteCommandPassthru($args)->execute();
   }
 
   private function newRemoteCommandFuture(array $argv) {
     return $this->newRemoteCommandEngine($argv)
       ->newFuture();
   }
 
   private function newRemoteCommandPassthru(array $argv) {
     return $this->newRemoteCommandEngine($argv)
       ->setPassthru(true)
       ->newFuture();
   }
 
   private function newRemoteCommandEngine(array $argv) {
     return DiffusionCommandEngine::newCommandEngine($this)
       ->setArgv($argv)
       ->setCredentialPHID($this->getCredentialPHID())
       ->setURI($this->getRemoteURIObject());
   }
 
 /* -(  Local Command Execution  )-------------------------------------------- */
 
 
   public function execLocalCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newLocalCommandFuture($args)->resolve();
   }
 
   public function execxLocalCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newLocalCommandFuture($args)->resolvex();
   }
 
   public function getLocalCommandFuture($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newLocalCommandFuture($args);
   }
 
   public function passthruLocalCommand($pattern /* , $arg, ... */) {
     $args = func_get_args();
     return $this->newLocalCommandPassthru($args)->execute();
   }
 
   private function newLocalCommandFuture(array $argv) {
     $this->assertLocalExists();
 
     $future = DiffusionCommandEngine::newCommandEngine($this)
       ->setArgv($argv)
       ->newFuture();
 
     if ($this->usesLocalWorkingCopy()) {
       $future->setCWD($this->getLocalPath());
     }
 
     return $future;
   }
 
   private function newLocalCommandPassthru(array $argv) {
     $this->assertLocalExists();
 
     $future = DiffusionCommandEngine::newCommandEngine($this)
       ->setArgv($argv)
       ->setPassthru(true)
       ->newFuture();
 
     if ($this->usesLocalWorkingCopy()) {
       $future->setCWD($this->getLocalPath());
     }
 
     return $future;
   }
 
   public function getURI() {
     $short_name = $this->getRepositorySlug();
     if (strlen($short_name)) {
       return "/source/{$short_name}/";
     }
 
     $callsign = $this->getCallsign();
     if (strlen($callsign)) {
       return "/diffusion/{$callsign}/";
     }
 
     $id = $this->getID();
     return "/diffusion/{$id}/";
   }
 
   public function getPathURI($path) {
     return $this->getURI().ltrim($path, '/');
   }
 
   public function getCommitURI($identifier) {
     $callsign = $this->getCallsign();
     if (strlen($callsign)) {
       return "/r{$callsign}{$identifier}";
     }
 
     $id = $this->getID();
     return "/R{$id}:{$identifier}";
   }
 
   public static function parseRepositoryServicePath($request_path, $vcs) {
     $is_git = ($vcs == PhabricatorRepositoryType::REPOSITORY_TYPE_GIT);
 
     $patterns = array(
       '(^'.
         '(?P<base>/?(?:diffusion|source)/(?P<identifier>[^/]+))'.
         '(?P<path>.*)'.
       '\z)',
     );
 
     $identifier = null;
     foreach ($patterns as $pattern) {
       $matches = null;
       if (!preg_match($pattern, $request_path, $matches)) {
         continue;
       }
 
       $identifier = $matches['identifier'];
       if ($is_git) {
         $identifier = preg_replace('/\\.git\z/', '', $identifier);
       }
 
       $base = $matches['base'];
       $path = $matches['path'];
       break;
     }
 
     if ($identifier === null) {
       return null;
     }
 
     return array(
       'identifier' => $identifier,
       'base' => $base,
       'path' => $path,
     );
   }
 
   public function getCanonicalPath($request_path) {
     $standard_pattern =
       '(^'.
         '(?P<prefix>/(?:diffusion|source)/)'.
         '(?P<identifier>[^/]+)'.
         '(?P<suffix>(?:/.*)?)'.
       '\z)';
 
     $matches = null;
     if (preg_match($standard_pattern, $request_path, $matches)) {
       $suffix = $matches['suffix'];
       return $this->getPathURI($suffix);
     }
 
     $commit_pattern =
       '(^'.
         '(?P<prefix>/)'.
         '(?P<monogram>'.
           '(?:'.
             'r(?P<repositoryCallsign>[A-Z]+)'.
             '|'.
             'R(?P<repositoryID>[1-9]\d*):'.
           ')'.
           '(?P<commit>[a-f0-9]+)'.
         ')'.
       '\z)';
 
     $matches = null;
     if (preg_match($commit_pattern, $request_path, $matches)) {
       $commit = $matches['commit'];
       return $this->getCommitURI($commit);
     }
 
     return null;
   }
 
   public function generateURI(array $params) {
     $req_branch = false;
     $req_commit = false;
 
     $action = idx($params, 'action');
     switch ($action) {
       case 'history':
       case 'graph':
       case 'clone':
       case 'blame':
       case 'browse':
       case 'document':
       case 'change':
       case 'lastmodified':
       case 'tags':
       case 'branches':
       case 'lint':
       case 'pathtree':
       case 'refs':
       case 'compare':
         break;
       case 'branch':
         // NOTE: This does not actually require a branch, and won't have one
         // in Subversion. Possibly this should be more clear.
         break;
       case 'commit':
       case 'rendering-ref':
         $req_commit = true;
         break;
       default:
         throw new Exception(
           pht(
             'Action "%s" is not a valid repository URI action.',
             $action));
     }
 
     $path     = idx($params, 'path');
     $branch   = idx($params, 'branch');
     $commit   = idx($params, 'commit');
     $line     = idx($params, 'line');
 
     $head = idx($params, 'head');
     $against = idx($params, 'against');
 
     if ($req_commit && !strlen($commit)) {
       throw new Exception(
         pht(
           'Diffusion URI action "%s" requires commit!',
           $action));
     }
 
     if ($req_branch && !strlen($branch)) {
       throw new Exception(
         pht(
           'Diffusion URI action "%s" requires branch!',
           $action));
     }
 
     if ($action === 'commit') {
       return $this->getCommitURI($commit);
     }
 
     if (strlen($path)) {
       $path = ltrim($path, '/');
       $path = str_replace(array(';', '$'), array(';;', '$$'), $path);
       $path = phutil_escape_uri($path);
     }
 
     $raw_branch = $branch;
     if (strlen($branch)) {
       $branch = phutil_escape_uri_path_component($branch);
       $path = "{$branch}/{$path}";
     }
 
     $raw_commit = $commit;
     if (strlen($commit)) {
       $commit = str_replace('$', '$$', $commit);
       $commit = ';'.phutil_escape_uri($commit);
     }
 
     if (strlen($line)) {
       $line = '$'.phutil_escape_uri($line);
     }
 
     $query = array();
     switch ($action) {
       case 'change':
       case 'history':
       case 'graph':
       case 'blame':
       case 'browse':
       case 'document':
       case 'lastmodified':
       case 'tags':
       case 'branches':
       case 'lint':
       case 'pathtree':
       case 'refs':
         $uri = $this->getPathURI("/{$action}/{$path}{$commit}{$line}");
         break;
       case 'compare':
         $uri = $this->getPathURI("/{$action}/");
         if (strlen($head)) {
           $query['head'] = $head;
         } else if (strlen($raw_commit)) {
           $query['commit'] = $raw_commit;
         } else if (strlen($raw_branch)) {
           $query['head'] = $raw_branch;
         }
 
         if (strlen($against)) {
           $query['against'] = $against;
         }
         break;
       case 'branch':
         if (strlen($path)) {
           $uri = $this->getPathURI("/repository/{$path}");
         } else {
           $uri = $this->getPathURI('/');
         }
         break;
       case 'external':
         $commit = ltrim($commit, ';');
         $uri = "/diffusion/external/{$commit}/";
         break;
       case 'rendering-ref':
         // This isn't a real URI per se, it's passed as a query parameter to
         // the ajax changeset stuff but then we parse it back out as though
         // it came from a URI.
         $uri = rawurldecode("{$path}{$commit}");
         break;
       case 'clone':
         $uri = $this->getPathURI("/{$action}/");
       break;
     }
 
     if ($action == 'rendering-ref') {
       return $uri;
     }
 
     $uri = new PhutilURI($uri);
 
     if (isset($params['lint'])) {
       $params['params'] = idx($params, 'params', array()) + array(
         'lint' => $params['lint'],
       );
     }
 
     $query = idx($params, 'params', array()) + $query;
 
     if ($query) {
       $uri->setQueryParams($query);
     }
 
     return $uri;
   }
 
   public function updateURIIndex() {
     $indexes = array();
 
     $uris = $this->getURIs();
     foreach ($uris as $uri) {
       if ($uri->getIsDisabled()) {
         continue;
       }
 
       $indexes[] = $uri->getNormalizedURI();
     }
 
     PhabricatorRepositoryURIIndex::updateRepositoryURIs(
       $this->getPHID(),
       $indexes);
 
     return $this;
   }
 
   public function isTracked() {
     $status = $this->getDetail('tracking-enabled');
     $map = self::getStatusMap();
     $spec = idx($map, $status);
 
     if (!$spec) {
       if ($status) {
         $status = self::STATUS_ACTIVE;
       } else {
         $status = self::STATUS_INACTIVE;
       }
       $spec = idx($map, $status);
     }
 
     return (bool)idx($spec, 'isTracked', false);
   }
 
   public function getDefaultBranch() {
     $default = $this->getDetail('default-branch');
     if (strlen($default)) {
       return $default;
     }
 
     $default_branches = array(
       PhabricatorRepositoryType::REPOSITORY_TYPE_GIT        => 'master',
       PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL  => 'default',
     );
 
     return idx($default_branches, $this->getVersionControlSystem());
   }
 
   public function getDefaultArcanistBranch() {
     return coalesce($this->getDefaultBranch(), 'svn');
   }
 
   private function isBranchInFilter($branch, $filter_key) {
     $vcs = $this->getVersionControlSystem();
 
     $is_git = ($vcs == PhabricatorRepositoryType::REPOSITORY_TYPE_GIT);
 
     $use_filter = ($is_git);
     if (!$use_filter) {
       // If this VCS doesn't use filters, pass everything through.
       return true;
     }
 
 
     $filter = $this->getDetail($filter_key, array());
 
     // If there's no filter set, let everything through.
     if (!$filter) {
       return true;
     }
 
     // If this branch isn't literally named `regexp(...)`, and it's in the
     // filter list, let it through.
     if (isset($filter[$branch])) {
       if (self::extractBranchRegexp($branch) === null) {
         return true;
       }
     }
 
     // If the branch matches a regexp, let it through.
     foreach ($filter as $pattern => $ignored) {
       $regexp = self::extractBranchRegexp($pattern);
       if ($regexp !== null) {
         if (preg_match($regexp, $branch)) {
           return true;
         }
       }
     }
 
     // Nothing matched, so filter this branch out.
     return false;
   }
 
   public static function extractBranchRegexp($pattern) {
     $matches = null;
     if (preg_match('/^regexp\\((.*)\\)\z/', $pattern, $matches)) {
       return $matches[1];
     }
     return null;
   }
 
   public function shouldTrackRef(DiffusionRepositoryRef $ref) {
     // At least for now, don't track the staging area tags.
     if ($ref->isTag()) {
       if (preg_match('(^phabricator/)', $ref->getShortName())) {
         return false;
       }
     }
 
     if (!$ref->isBranch()) {
       return true;
     }
 
     return $this->shouldTrackBranch($ref->getShortName());
   }
 
   public function shouldTrackBranch($branch) {
     return $this->isBranchInFilter($branch, 'branch-filter');
   }
 
   public function formatCommitName($commit_identifier, $local = false) {
     $vcs = $this->getVersionControlSystem();
 
     $type_git = PhabricatorRepositoryType::REPOSITORY_TYPE_GIT;
     $type_hg = PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL;
 
     $is_git = ($vcs == $type_git);
     $is_hg = ($vcs == $type_hg);
     if ($is_git || $is_hg) {
       $name = substr($commit_identifier, 0, 12);
       $need_scope = false;
     } else {
       $name = $commit_identifier;
       $need_scope = true;
     }
 
     if (!$local) {
       $need_scope = true;
     }
 
     if ($need_scope) {
       $callsign = $this->getCallsign();
       if ($callsign) {
         $scope = "r{$callsign}";
       } else {
         $id = $this->getID();
         $scope = "R{$id}:";
       }
       $name = $scope.$name;
     }
 
     return $name;
   }
 
   public function isImporting() {
     return (bool)$this->getDetail('importing', false);
   }
 
   public function isNewlyInitialized() {
     return (bool)$this->getDetail('newly-initialized', false);
   }
 
   public function loadImportProgress() {
     $progress = queryfx_all(
       $this->establishConnection('r'),
       'SELECT importStatus, count(*) N FROM %T WHERE repositoryID = %d
         GROUP BY importStatus',
       id(new PhabricatorRepositoryCommit())->getTableName(),
       $this->getID());
 
     $done = 0;
     $total = 0;
     foreach ($progress as $row) {
       $total += $row['N'] * 4;
       $status = $row['importStatus'];
       if ($status & PhabricatorRepositoryCommit::IMPORTED_MESSAGE) {
         $done += $row['N'];
       }
       if ($status & PhabricatorRepositoryCommit::IMPORTED_CHANGE) {
         $done += $row['N'];
       }
       if ($status & PhabricatorRepositoryCommit::IMPORTED_OWNERS) {
         $done += $row['N'];
       }
       if ($status & PhabricatorRepositoryCommit::IMPORTED_HERALD) {
         $done += $row['N'];
       }
     }
 
     if ($total) {
       $ratio = ($done / $total);
     } else {
       $ratio = 0;
     }
 
     // Cap this at "99.99%", because it's confusing to users when the actual
     // fraction is "99.996%" and it rounds up to "100.00%".
     if ($ratio > 0.9999) {
       $ratio = 0.9999;
     }
 
     return $ratio;
   }
 
   /**
    * Should this repository publish feed, notifications, audits, and email?
    *
    * We do not publish information about repositories during initial import,
    * or if the repository has been set not to publish.
    */
   public function shouldPublish() {
     if ($this->isImporting()) {
       return false;
     }
 
     if ($this->getDetail('herald-disabled')) {
       return false;
     }
 
     return true;
   }
 
 
 /* -(  Autoclose  )---------------------------------------------------------- */
 
 
   public function shouldAutocloseRef(DiffusionRepositoryRef $ref) {
     if (!$ref->isBranch()) {
       return false;
     }
 
     return $this->shouldAutocloseBranch($ref->getShortName());
   }
 
   /**
    * Determine if autoclose is active for a branch.
    *
    * For more details about why, use @{method:shouldSkipAutocloseBranch}.
    *
    * @param string Branch name to check.
    * @return bool True if autoclose is active for the branch.
    * @task autoclose
    */
   public function shouldAutocloseBranch($branch) {
     return ($this->shouldSkipAutocloseBranch($branch) === null);
   }
 
   /**
    * Determine if autoclose is active for a commit.
    *
    * For more details about why, use @{method:shouldSkipAutocloseCommit}.
    *
    * @param PhabricatorRepositoryCommit Commit to check.
    * @return bool True if autoclose is active for the commit.
    * @task autoclose
    */
   public function shouldAutocloseCommit(PhabricatorRepositoryCommit $commit) {
     return ($this->shouldSkipAutocloseCommit($commit) === null);
   }
 
 
   /**
    * Determine why autoclose should be skipped for a branch.
    *
    * This method gives a detailed reason why autoclose will be skipped. To
    * perform a simple test, use @{method:shouldAutocloseBranch}.
    *
    * @param string Branch name to check.
    * @return const|null Constant identifying reason to skip this branch, or null
    *   if autoclose is active.
    * @task autoclose
    */
   public function shouldSkipAutocloseBranch($branch) {
     $all_reason = $this->shouldSkipAllAutoclose();
     if ($all_reason) {
       return $all_reason;
     }
 
     if (!$this->shouldTrackBranch($branch)) {
       return self::BECAUSE_BRANCH_UNTRACKED;
     }
 
     if (!$this->isBranchInFilter($branch, 'close-commits-filter')) {
       return self::BECAUSE_BRANCH_NOT_AUTOCLOSE;
     }
 
     return null;
   }
 
 
   /**
    * Determine why autoclose should be skipped for a commit.
    *
    * This method gives a detailed reason why autoclose will be skipped. To
    * perform a simple test, use @{method:shouldAutocloseCommit}.
    *
    * @param PhabricatorRepositoryCommit Commit to check.
    * @return const|null Constant identifying reason to skip this commit, or null
    *   if autoclose is active.
    * @task autoclose
    */
   public function shouldSkipAutocloseCommit(
     PhabricatorRepositoryCommit $commit) {
 
     $all_reason = $this->shouldSkipAllAutoclose();
     if ($all_reason) {
       return $all_reason;
     }
 
     switch ($this->getVersionControlSystem()) {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
       case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
         return null;
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
         break;
       default:
         throw new Exception(pht('Unrecognized version control system.'));
     }
 
     $closeable_flag = PhabricatorRepositoryCommit::IMPORTED_CLOSEABLE;
     if (!$commit->isPartiallyImported($closeable_flag)) {
       return self::BECAUSE_NOT_ON_AUTOCLOSE_BRANCH;
     }
 
     return null;
   }
 
 
   /**
    * Determine why all autoclose operations should be skipped for this
    * repository.
    *
    * @return const|null Constant identifying reason to skip all autoclose
    *   operations, or null if autoclose operations are not blocked at the
    *   repository level.
    * @task autoclose
    */
   private function shouldSkipAllAutoclose() {
     if ($this->isImporting()) {
       return self::BECAUSE_REPOSITORY_IMPORTING;
     }
 
     if ($this->getDetail('disable-autoclose', false)) {
       return self::BECAUSE_AUTOCLOSE_DISABLED;
     }
 
     return null;
   }
 
 
 /* -(  Repository URI Management  )------------------------------------------ */
 
 
   /**
    * Get the remote URI for this repository.
    *
    * @return string
    * @task uri
    */
   public function getRemoteURI() {
     return (string)$this->getRemoteURIObject();
   }
 
 
   /**
    * Get the remote URI for this repository, including credentials if they're
    * used by this repository.
    *
    * @return PhutilOpaqueEnvelope URI, possibly including credentials.
    * @task uri
    */
   public function getRemoteURIEnvelope() {
     $uri = $this->getRemoteURIObject();
 
     $remote_protocol = $this->getRemoteProtocol();
     if ($remote_protocol == 'http' || $remote_protocol == 'https') {
       // For SVN, we use `--username` and `--password` flags separately, so
       // don't add any credentials here.
       if (!$this->isSVN()) {
         $credential_phid = $this->getCredentialPHID();
         if ($credential_phid) {
           $key = PassphrasePasswordKey::loadFromPHID(
             $credential_phid,
             PhabricatorUser::getOmnipotentUser());
 
           $uri->setUser($key->getUsernameEnvelope()->openEnvelope());
           $uri->setPass($key->getPasswordEnvelope()->openEnvelope());
         }
       }
     }
 
     return new PhutilOpaqueEnvelope((string)$uri);
   }
 
 
   /**
    * Get the clone (or checkout) URI for this repository, without authentication
    * information.
    *
    * @return string Repository URI.
    * @task uri
    */
   public function getPublicCloneURI() {
     return (string)$this->getCloneURIObject();
   }
 
 
   /**
    * Get the protocol for the repository's remote.
    *
    * @return string Protocol, like "ssh" or "git".
    * @task uri
    */
   public function getRemoteProtocol() {
     $uri = $this->getRemoteURIObject();
     return $uri->getProtocol();
   }
 
 
   /**
    * Get a parsed object representation of the repository's remote URI..
    *
    * @return wild A @{class@libphutil:PhutilURI}.
    * @task uri
    */
   public function getRemoteURIObject() {
     $raw_uri = $this->getDetail('remote-uri');
     if (!strlen($raw_uri)) {
       return new PhutilURI('');
     }
 
     if (!strncmp($raw_uri, '/', 1)) {
       return new PhutilURI('file://'.$raw_uri);
     }
 
     return new PhutilURI($raw_uri);
   }
 
 
   /**
    * Get the "best" clone/checkout URI for this repository, on any protocol.
    */
   public function getCloneURIObject() {
     if (!$this->isHosted()) {
       if ($this->isSVN()) {
         // Make sure we pick up the "Import Only" path for Subversion, so
         // the user clones the repository starting at the correct path, not
         // from the root.
         $base_uri = $this->getSubversionBaseURI();
         $base_uri = new PhutilURI($base_uri);
         $path = $base_uri->getPath();
         if (!$path) {
           $path = '/';
         }
 
         // If the trailing "@" is not required to escape the URI, strip it for
         // readability.
         if (!preg_match('/@.*@/', $path)) {
           $path = rtrim($path, '@');
         }
 
         $base_uri->setPath($path);
         return $base_uri;
       } else {
         return $this->getRemoteURIObject();
       }
     }
 
     // TODO: This should be cleaned up to deal with all the new URI handling.
     $another_copy = id(new PhabricatorRepositoryQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withPHIDs(array($this->getPHID()))
       ->needURIs(true)
       ->executeOne();
 
     $clone_uris = $another_copy->getCloneURIs();
     if (!$clone_uris) {
       return null;
     }
 
     return head($clone_uris)->getEffectiveURI();
   }
 
   private function getRawHTTPCloneURIObject() {
     $uri = PhabricatorEnv::getProductionURI($this->getURI());
     $uri = new PhutilURI($uri);
 
     if ($this->isGit()) {
       $uri->setPath($uri->getPath().$this->getCloneName().'.git');
     } else if ($this->isHg()) {
       $uri->setPath($uri->getPath().$this->getCloneName().'/');
     }
 
     return $uri;
   }
 
 
   /**
    * Determine if we should connect to the remote using SSH flags and
    * credentials.
    *
    * @return bool True to use the SSH protocol.
    * @task uri
    */
   private function shouldUseSSH() {
     if ($this->isHosted()) {
       return false;
     }
 
     $protocol = $this->getRemoteProtocol();
     if ($this->isSSHProtocol($protocol)) {
       return true;
     }
 
     return false;
   }
 
 
   /**
    * Determine if we should connect to the remote using HTTP flags and
    * credentials.
    *
    * @return bool True to use the HTTP protocol.
    * @task uri
    */
   private function shouldUseHTTP() {
     if ($this->isHosted()) {
       return false;
     }
 
     $protocol = $this->getRemoteProtocol();
     return ($protocol == 'http' || $protocol == 'https');
   }
 
 
   /**
    * Determine if we should connect to the remote using SVN flags and
    * credentials.
    *
    * @return bool True to use the SVN protocol.
    * @task uri
    */
   private function shouldUseSVNProtocol() {
     if ($this->isHosted()) {
       return false;
     }
 
     $protocol = $this->getRemoteProtocol();
     return ($protocol == 'svn');
   }
 
 
   /**
    * Determine if a protocol is SSH or SSH-like.
    *
    * @param string A protocol string, like "http" or "ssh".
    * @return bool True if the protocol is SSH-like.
    * @task uri
    */
   private function isSSHProtocol($protocol) {
     return ($protocol == 'ssh' || $protocol == 'svn+ssh');
   }
 
   public function delete() {
     $this->openTransaction();
 
       $paths = id(new PhabricatorOwnersPath())
         ->loadAllWhere('repositoryPHID = %s', $this->getPHID());
       foreach ($paths as $path) {
         $path->delete();
       }
 
       queryfx(
         $this->establishConnection('w'),
         'DELETE FROM %T WHERE repositoryPHID = %s',
         id(new PhabricatorRepositorySymbol())->getTableName(),
         $this->getPHID());
 
       $commits = id(new PhabricatorRepositoryCommit())
         ->loadAllWhere('repositoryID = %d', $this->getID());
       foreach ($commits as $commit) {
         // note PhabricatorRepositoryAuditRequests and
         // PhabricatorRepositoryCommitData are deleted here too.
         $commit->delete();
       }
 
       $uris = id(new PhabricatorRepositoryURI())
         ->loadAllWhere('repositoryPHID = %s', $this->getPHID());
       foreach ($uris as $uri) {
         $uri->delete();
       }
 
       $ref_cursors = id(new PhabricatorRepositoryRefCursor())
         ->loadAllWhere('repositoryPHID = %s', $this->getPHID());
       foreach ($ref_cursors as $cursor) {
         $cursor->delete();
       }
 
       $conn_w = $this->establishConnection('w');
 
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE repositoryID = %d',
         self::TABLE_FILESYSTEM,
         $this->getID());
 
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE repositoryID = %d',
         self::TABLE_PATHCHANGE,
         $this->getID());
 
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE repositoryID = %d',
         self::TABLE_SUMMARY,
         $this->getID());
 
       $result = parent::delete();
 
     $this->saveTransaction();
     return $result;
   }
 
   public function isGit() {
     $vcs = $this->getVersionControlSystem();
     return ($vcs == PhabricatorRepositoryType::REPOSITORY_TYPE_GIT);
   }
 
   public function isSVN() {
     $vcs = $this->getVersionControlSystem();
     return ($vcs == PhabricatorRepositoryType::REPOSITORY_TYPE_SVN);
   }
 
   public function isHg() {
     $vcs = $this->getVersionControlSystem();
     return ($vcs == PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL);
   }
 
   public function isHosted() {
     return (bool)$this->getDetail('hosting-enabled', false);
   }
 
   public function setHosted($enabled) {
     return $this->setDetail('hosting-enabled', $enabled);
   }
 
   public function canServeProtocol($protocol, $write) {
     if (!$this->isTracked()) {
       return false;
     }
 
     $clone_uris = $this->getCloneURIs();
     foreach ($clone_uris as $uri) {
       if ($uri->getBuiltinProtocol() !== $protocol) {
         continue;
       }
 
       $io_type = $uri->getEffectiveIoType();
       if ($io_type == PhabricatorRepositoryURI::IO_READWRITE) {
         return true;
       }
 
       if (!$write) {
         if ($io_type == PhabricatorRepositoryURI::IO_READ) {
           return true;
         }
       }
     }
 
     return false;
   }
 
   public function hasLocalWorkingCopy() {
     try {
       self::assertLocalExists();
       return true;
     } catch (Exception $ex) {
       return false;
     }
   }
 
   /**
    * Raise more useful errors when there are basic filesystem problems.
    */
   private function assertLocalExists() {
     if (!$this->usesLocalWorkingCopy()) {
       return;
     }
 
     $local = $this->getLocalPath();
     Filesystem::assertExists($local);
     Filesystem::assertIsDirectory($local);
     Filesystem::assertReadable($local);
   }
 
   /**
    * Determine if the working copy is bare or not. In Git, this corresponds
    * to `--bare`. In Mercurial, `--noupdate`.
    */
   public function isWorkingCopyBare() {
     switch ($this->getVersionControlSystem()) {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
       case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
         return false;
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
         $local = $this->getLocalPath();
         if (Filesystem::pathExists($local.'/.git')) {
           return false;
         } else {
           return true;
         }
     }
   }
 
   public function usesLocalWorkingCopy() {
     switch ($this->getVersionControlSystem()) {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
         return $this->isHosted();
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
       case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
         return true;
     }
   }
 
   public function getHookDirectories() {
     $directories = array();
     if (!$this->isHosted()) {
       return $directories;
     }
 
     $root = $this->getLocalPath();
 
     switch ($this->getVersionControlSystem()) {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
         if ($this->isWorkingCopyBare()) {
           $directories[] = $root.'/hooks/pre-receive-phabricator.d/';
         } else {
           $directories[] = $root.'/.git/hooks/pre-receive-phabricator.d/';
         }
         break;
       case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
         $directories[] = $root.'/hooks/pre-commit-phabricator.d/';
         break;
       case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
         // NOTE: We don't support custom Mercurial hooks for now because they're
         // messy and we can't easily just drop a `hooks.d/` directory next to
         // the hooks.
         break;
     }
 
     return $directories;
   }
 
   public function canDestroyWorkingCopy() {
     if ($this->isHosted()) {
       // Never destroy hosted working copies.
       return false;
     }
 
     $default_path = PhabricatorEnv::getEnvConfig(
       'repository.default-local-path');
     return Filesystem::isDescendant($this->getLocalPath(), $default_path);
   }
 
   public function canUsePathTree() {
     return !$this->isSVN();
   }
 
   public function canUseGitLFS() {
     if (!$this->isGit()) {
       return false;
     }
 
     if (!$this->isHosted()) {
       return false;
     }
 
     if (!PhabricatorEnv::getEnvConfig('diffusion.allow-git-lfs')) {
       return false;
     }
 
     return true;
   }
 
   public function getGitLFSURI($path = null) {
     if (!$this->canUseGitLFS()) {
       throw new Exception(
         pht(
           'This repository does not support Git LFS, so Git LFS URIs can '.
           'not be generated for it.'));
     }
 
     $uri = $this->getRawHTTPCloneURIObject();
     $uri = (string)$uri;
     $uri = $uri.'/'.$path;
 
     return $uri;
   }
 
   public function canMirror() {
     if ($this->isGit() || $this->isHg()) {
       return true;
     }
 
     return false;
   }
 
   public function canAllowDangerousChanges() {
     if (!$this->isHosted()) {
       return false;
     }
 
     // In Git and Mercurial, ref deletions and rewrites are dangerous.
     // In Subversion, editing revprops is dangerous.
 
     return true;
   }
 
   public function shouldAllowDangerousChanges() {
     return (bool)$this->getDetail('allow-dangerous-changes');
   }
 
   public function canAllowEnormousChanges() {
     if (!$this->isHosted()) {
       return false;
     }
 
     return true;
   }
 
   public function shouldAllowEnormousChanges() {
     return (bool)$this->getDetail('allow-enormous-changes');
   }
 
   public function writeStatusMessage(
     $status_type,
     $status_code,
     array $parameters = array()) {
 
     $table = new PhabricatorRepositoryStatusMessage();
     $conn_w = $table->establishConnection('w');
     $table_name = $table->getTableName();
 
     if ($status_code === null) {
       queryfx(
         $conn_w,
         'DELETE FROM %T WHERE repositoryID = %d AND statusType = %s',
         $table_name,
         $this->getID(),
         $status_type);
     } else {
       // If the existing message has the same code (e.g., we just hit an
       // error and also previously hit an error) we increment the message
       // count. This allows us to determine how many times in a row we've
       // run into an error.
 
       // NOTE: The assignments in "ON DUPLICATE KEY UPDATE" are evaluated
       // in order, so the "messageCount" assignment must occur before the
       // "statusCode" assignment. See T11705.
 
       queryfx(
         $conn_w,
         'INSERT INTO %T
           (repositoryID, statusType, statusCode, parameters, epoch,
             messageCount)
           VALUES (%d, %s, %s, %s, %d, %d)
           ON DUPLICATE KEY UPDATE
             messageCount =
               IF(
                 statusCode = VALUES(statusCode),
                 messageCount + VALUES(messageCount),
                 VALUES(messageCount)),
             statusCode = VALUES(statusCode),
             parameters = VALUES(parameters),
             epoch = VALUES(epoch)',
         $table_name,
         $this->getID(),
         $status_type,
         $status_code,
         json_encode($parameters),
         time(),
         1);
     }
 
     return $this;
   }
 
   public static function assertValidRemoteURI($uri) {
     if (trim($uri) != $uri) {
       throw new Exception(
         pht('The remote URI has leading or trailing whitespace.'));
     }
 
     $uri_object = new PhutilURI($uri);
     $protocol = $uri_object->getProtocol();
 
     // Catch confusion between Git/SCP-style URIs and normal URIs. See T3619
     // for discussion. This is usually a user adding "ssh://" to an implicit
     // SSH Git URI.
     if ($protocol == 'ssh') {
       if (preg_match('(^[^:@]+://[^/:]+:[^\d])', $uri)) {
         throw new Exception(
           pht(
             "The remote URI is not formatted correctly. Remote URIs ".
             "with an explicit protocol should be in the form ".
             "'%s', not '%s'. The '%s' syntax is only valid in SCP-style URIs.",
             'proto://domain/path',
             'proto://domain:/path',
             ':/path'));
       }
     }
 
     switch ($protocol) {
       case 'ssh':
       case 'http':
       case 'https':
       case 'git':
       case 'svn':
       case 'svn+ssh':
         break;
       default:
         // NOTE: We're explicitly rejecting 'file://' because it can be
         // used to clone from the working copy of another repository on disk
         // that you don't normally have permission to access.
 
         throw new Exception(
           pht(
             'The URI protocol is unrecognized. It should begin with '.
             '"%s", "%s", "%s", "%s", "%s", "%s", or be in the form "%s".',
             'ssh://',
             'http://',
             'https://',
             'git://',
             'svn://',
             'svn+ssh://',
             'git@domain.com:path'));
     }
 
     return true;
   }
 
 
   /**
    * Load the pull frequency for this repository, based on the time since the
    * last activity.
    *
    * We pull rarely used repositories less frequently. This finds the most
    * recent commit which is older than the current time (which prevents us from
    * spinning on repositories with a silly commit post-dated to some time in
    * 2037). We adjust the pull frequency based on when the most recent commit
    * occurred.
    *
    * @param   int   The minimum update interval to use, in seconds.
    * @return  int   Repository update interval, in seconds.
    */
   public function loadUpdateInterval($minimum = 15) {
     // First, check if we've hit errors recently. If we have, wait one period
     // for each consecutive error. Normally, this corresponds to a backoff of
     // 15s, 30s, 45s, etc.
 
     $message_table = new PhabricatorRepositoryStatusMessage();
     $conn = $message_table->establishConnection('r');
     $error_count = queryfx_one(
       $conn,
       'SELECT MAX(messageCount) error_count FROM %T
         WHERE repositoryID = %d
         AND statusType IN (%Ls)
         AND statusCode IN (%Ls)',
       $message_table->getTableName(),
       $this->getID(),
       array(
         PhabricatorRepositoryStatusMessage::TYPE_INIT,
         PhabricatorRepositoryStatusMessage::TYPE_FETCH,
       ),
       array(
         PhabricatorRepositoryStatusMessage::CODE_ERROR,
       ));
 
     $error_count = (int)$error_count['error_count'];
     if ($error_count > 0) {
       return (int)($minimum * $error_count);
     }
 
     // If a repository is still importing, always pull it as frequently as
     // possible. This prevents us from hanging for a long time at 99.9% when
     // importing an inactive repository.
     if ($this->isImporting()) {
       return $minimum;
     }
 
     $window_start = (PhabricatorTime::getNow() + $minimum);
 
     $table = id(new PhabricatorRepositoryCommit());
     $last_commit = queryfx_one(
       $table->establishConnection('r'),
       'SELECT epoch FROM %T
         WHERE repositoryID = %d AND epoch <= %d
         ORDER BY epoch DESC LIMIT 1',
       $table->getTableName(),
       $this->getID(),
       $window_start);
     if ($last_commit) {
       $time_since_commit = ($window_start - $last_commit['epoch']);
     } else {
       // If the repository has no commits, treat the creation date as
       // though it were the date of the last commit. This makes empty
       // repositories update quickly at first but slow down over time
       // if they don't see any activity.
       $time_since_commit = ($window_start - $this->getDateCreated());
     }
 
     $last_few_days = phutil_units('3 days in seconds');
 
     if ($time_since_commit <= $last_few_days) {
       // For repositories with activity in the recent past, we wait one
       // extra second for every 10 minutes since the last commit. This
       // shorter backoff is intended to handle weekends and other short
       // breaks from development.
       $smart_wait = ($time_since_commit / 600);
     } else {
       // For repositories without recent activity, we wait one extra second
       // for every 4 minutes since the last commit. This longer backoff
       // handles rarely used repositories, up to the maximum.
       $smart_wait = ($time_since_commit / 240);
     }
 
     // We'll never wait more than 6 hours to pull a repository.
     $longest_wait = phutil_units('6 hours in seconds');
     $smart_wait = min($smart_wait, $longest_wait);
     $smart_wait = max($minimum, $smart_wait);
 
     return (int)$smart_wait;
   }
 
 
   /**
    * Retrieve the service URI for the device hosting this repository.
    *
    * See @{method:newConduitClient} for a general discussion of interacting
    * with repository services. This method provides lower-level resolution of
    * services, returning raw URIs.
    *
    * @param PhabricatorUser Viewing user.
    * @param map<string, wild> Constraints on selectable services.
    * @return string|null URI, or `null` for local repositories.
    */
   public function getAlmanacServiceURI(
     PhabricatorUser $viewer,
     array $options) {
 
     PhutilTypeSpec::checkMap(
       $options,
       array(
         'neverProxy' => 'bool',
         'protocols' => 'list<string>',
         'writable' => 'optional bool',
       ));
 
     $never_proxy = $options['neverProxy'];
     $protocols = $options['protocols'];
     $writable = idx($options, 'writable', false);
 
     $cache_key = $this->getAlmanacServiceCacheKey();
     if (!$cache_key) {
       return null;
     }
 
     $cache = PhabricatorCaches::getMutableStructureCache();
     $uris = $cache->getKey($cache_key, false);
 
     // If we haven't built the cache yet, build it now.
     if ($uris === false) {
       $uris = $this->buildAlmanacServiceURIs();
       $cache->setKey($cache_key, $uris);
     }
 
     if ($uris === null) {
       return null;
     }
 
     $local_device = AlmanacKeys::getDeviceID();
     if ($never_proxy && !$local_device) {
       throw new Exception(
         pht(
           'Unable to handle proxied service request. This device is not '.
           'registered, so it can not identify local services. Register '.
           'this device before sending requests here.'));
     }
 
     $protocol_map = array_fuse($protocols);
 
     $results = array();
     foreach ($uris as $uri) {
       // If we're never proxying this and it's locally satisfiable, return
       // `null` to tell the caller to handle it locally. If we're allowed to
       // proxy, we skip this check and may proxy the request to ourselves.
       // (That proxied request will end up here with proxying forbidden,
       // return `null`, and then the request will actually run.)
 
       if ($local_device && $never_proxy) {
         if ($uri['device'] == $local_device) {
           return null;
         }
       }
 
       if (isset($protocol_map[$uri['protocol']])) {
         $results[] = $uri;
       }
     }
 
     if (!$results) {
       throw new Exception(
         pht(
           'The Almanac service for this repository is not bound to any '.
           'interfaces which support the required protocols (%s).',
           implode(', ', $protocols)));
     }
 
     if ($never_proxy) {
       throw new Exception(
         pht(
           'Refusing to proxy a repository request from a cluster host. '.
           'Cluster hosts must correctly route their intracluster requests.'));
     }
 
     if (count($results) > 1) {
       if (!$this->supportsSynchronization()) {
         throw new Exception(
           pht(
             'Repository "%s" is bound to multiple active repository hosts, '.
             'but this repository does not support cluster synchronization. '.
             'Declusterize this repository or move it to a service with only '.
             'one host.',
             $this->getDisplayName()));
       }
     }
 
     // If we require a writable device, remove URIs which aren't writable.
     if ($writable) {
       foreach ($results as $key => $uri) {
         if (!$uri['writable']) {
           unset($results[$key]);
         }
       }
 
       if (!$results) {
         throw new Exception(
           pht(
             'This repository ("%s") is not writable with the given '.
             'protocols (%s). The Almanac service for this repository has no '.
             'writable bindings that support these protocols.',
             $this->getDisplayName(),
             implode(', ', $protocols)));
       }
     }
 
-    shuffle($results);
+    if ($writable) {
+      $results = $this->sortWritableAlmanacServiceURIs($results);
+    } else {
+      shuffle($results);
+    }
 
     $result = head($results);
     return $result['uri'];
   }
 
+  private function sortWritableAlmanacServiceURIs(array $results) {
+    // See T13109 for discussion of how this method routes requests.
+
+    // In the absence of other rules, we'll send traffic to devices randomly.
+    // We also want to select randomly among nodes which are equally good
+    // candidates to receive the write, and accomplish that by shuffling the
+    // list up front.
+    shuffle($results);
+
+    $order = array();
+
+    // If some device is currently holding the write lock, send all requests
+    // to that device. We're trying to queue writes on a single device so they
+    // do not need to wait for read synchronization after earlier writes
+    // complete.
+    $writer = PhabricatorRepositoryWorkingCopyVersion::loadWriter(
+      $this->getPHID());
+    if ($writer) {
+      $device_phid = $writer->getWriteProperty('devicePHID');
+      foreach ($results as $key => $result) {
+        if ($result['devicePHID'] === $device_phid) {
+          $order[] = $key;
+        }
+      }
+    }
+
+    // If no device is currently holding the write lock, try to send requests
+    // to a device which is already up to date and will not need to synchronize
+    // before it can accept the write.
+    $versions = PhabricatorRepositoryWorkingCopyVersion::loadVersions(
+      $this->getPHID());
+    if ($versions) {
+      $max_version = (int)max(mpull($versions, 'getRepositoryVersion'));
+
+      $max_devices = array();
+      foreach ($versions as $version) {
+        if ($version->getRepositoryVersion() == $max_version) {
+          $max_devices[] = $version->getDevicePHID();
+        }
+      }
+      $max_devices = array_fuse($max_devices);
+
+      foreach ($results as $key => $result) {
+        if (isset($max_devices[$result['devicePHID']])) {
+          $order[] = $key;
+        }
+      }
+    }
+
+    // Reorder the results, putting any we've selected as preferred targets for
+    // the write at the head of the list.
+    $results = array_select_keys($results, $order) + $results;
+
+    return $results;
+  }
+
   public function supportsSynchronization() {
     // TODO: For now, this is only supported for Git.
     if (!$this->isGit()) {
       return false;
     }
 
     return true;
   }
 
   public function getAlmanacServiceCacheKey() {
     $service_phid = $this->getAlmanacServicePHID();
     if (!$service_phid) {
       return null;
     }
 
     $repository_phid = $this->getPHID();
 
     $parts = array(
       "repo({$repository_phid})",
       "serv({$service_phid})",
-      'v2',
+      'v3',
     );
 
     return implode('.', $parts);
   }
 
   private function buildAlmanacServiceURIs() {
     $service = $this->loadAlmanacService();
     if (!$service) {
       return null;
     }
 
     $bindings = $service->getActiveBindings();
     if (!$bindings) {
       throw new Exception(
         pht(
           'The Almanac service for this repository is not bound to any '.
           'interfaces.'));
     }
 
     $uris = array();
     foreach ($bindings as $binding) {
       $iface = $binding->getInterface();
 
       $uri = $this->getClusterRepositoryURIFromBinding($binding);
       $protocol = $uri->getProtocol();
       $device_name = $iface->getDevice()->getName();
+      $device_phid = $iface->getDevice()->getPHID();
 
       $uris[] = array(
         'protocol' => $protocol,
         'uri' => (string)$uri,
         'device' => $device_name,
         'writable' => (bool)$binding->getAlmanacPropertyValue('writable'),
+        'devicePHID' => $device_phid,
       );
     }
 
     return $uris;
   }
 
   /**
    * Build a new Conduit client in order to make a service call to this
    * repository.
    *
    * If the repository is hosted locally, this method may return `null`. The
    * caller should use `ConduitCall` or other local logic to complete the
    * request.
    *
    * By default, we will return a @{class:ConduitClient} for any repository with
    * a service, even if that service is on the current device.
    *
    * We do this because this configuration does not make very much sense in a
    * production context, but is very common in a test/development context
    * (where the developer's machine is both the web host and the repository
    * service). By proxying in development, we get more consistent behavior
    * between development and production, and don't have a major untested
    * codepath.
    *
    * The `$never_proxy` parameter can be used to prevent this local proxying.
    * If the flag is passed:
    *
    *   - The method will return `null` (implying a local service call)
    *     if the repository service is hosted on the current device.
    *   - The method will throw if it would need to return a client.
    *
    * This is used to prevent loops in Conduit: the first request will proxy,
    * even in development, but the second request will be identified as a
    * cluster request and forced not to proxy.
    *
    * For lower-level service resolution, see @{method:getAlmanacServiceURI}.
    *
    * @param PhabricatorUser Viewing user.
    * @param bool `true` to throw if a client would be returned.
    * @return ConduitClient|null Client, or `null` for local repositories.
    */
   public function newConduitClient(
     PhabricatorUser $viewer,
     $never_proxy = false) {
 
     $uri = $this->getAlmanacServiceURI(
       $viewer,
       array(
         'neverProxy' => $never_proxy,
         'protocols' => array(
           'http',
           'https',
         ),
 
         // At least today, no Conduit call can ever write to a repository,
         // so it's fine to send anything to a read-only node.
         'writable' => false,
       ));
     if ($uri === null) {
       return null;
     }
 
     $domain = id(new PhutilURI(PhabricatorEnv::getURI('/')))->getDomain();
 
     $client = id(new ConduitClient($uri))
       ->setHost($domain);
 
     if ($viewer->isOmnipotent()) {
       // If the caller is the omnipotent user (normally, a daemon), we will
       // sign the request with this host's asymmetric keypair.
 
       $public_path = AlmanacKeys::getKeyPath('device.pub');
       try {
         $public_key = Filesystem::readFile($public_path);
       } catch (Exception $ex) {
         throw new PhutilAggregateException(
           pht(
             'Unable to read device public key while attempting to make '.
             'authenticated method call within the Phabricator cluster. '.
             'Use `%s` to register keys for this device. Exception: %s',
             'bin/almanac register',
             $ex->getMessage()),
           array($ex));
       }
 
       $private_path = AlmanacKeys::getKeyPath('device.key');
       try {
         $private_key = Filesystem::readFile($private_path);
         $private_key = new PhutilOpaqueEnvelope($private_key);
       } catch (Exception $ex) {
         throw new PhutilAggregateException(
           pht(
             'Unable to read device private key while attempting to make '.
             'authenticated method call within the Phabricator cluster. '.
             'Use `%s` to register keys for this device. Exception: %s',
             'bin/almanac register',
             $ex->getMessage()),
           array($ex));
       }
 
       $client->setSigningKeys($public_key, $private_key);
     } else {
       // If the caller is a normal user, we generate or retrieve a cluster
       // API token.
 
       $token = PhabricatorConduitToken::loadClusterTokenForUser($viewer);
       if ($token) {
         $client->setConduitToken($token->getToken());
       }
     }
 
     return $client;
   }
 
   public function getPassthroughEnvironmentalVariables() {
     $env = $_ENV;
 
     if ($this->isGit()) {
       // $_ENV does not populate in CLI contexts if "E" is missing from
       // "variables_order" in PHP config. Currently, we do not require this
       // to be configured. Since it may not be, explicitly bring expected Git
       // environmental variables into scope. This list is not exhaustive, but
       // only lists variables with a known impact on commit hook behavior.
 
       // This can be removed if we later require "E" in "variables_order".
 
       $git_env = array(
         'GIT_OBJECT_DIRECTORY',
         'GIT_ALTERNATE_OBJECT_DIRECTORIES',
         'GIT_QUARANTINE_PATH',
       );
       foreach ($git_env as $key) {
         $value = getenv($key);
         if (strlen($value)) {
           $env[$key] = $value;
         }
       }
 
       $key = 'GIT_PUSH_OPTION_COUNT';
       $git_count = getenv($key);
       if (strlen($git_count)) {
         $git_count = (int)$git_count;
         $env[$key] = $git_count;
         for ($ii = 0; $ii < $git_count; $ii++) {
           $key = 'GIT_PUSH_OPTION_'.$ii;
           $env[$key] = getenv($key);
         }
       }
     }
 
     $result = array();
     foreach ($env as $key => $value) {
       // In Git, pass anything matching "GIT_*" though. Some of these variables
       // need to be preserved to allow `git` operations to work properly when
       // running from commit hooks.
       if ($this->isGit()) {
         if (preg_match('/^GIT_/', $key)) {
           $result[$key] = $value;
         }
       }
     }
 
     return $result;
   }
 
   public function supportsBranchComparison() {
     return $this->isGit();
   }
 
 /* -(  Repository URIs  )---------------------------------------------------- */
 
 
   public function attachURIs(array $uris) {
     $custom_map = array();
     foreach ($uris as $key => $uri) {
       $builtin_key = $uri->getRepositoryURIBuiltinKey();
       if ($builtin_key !== null) {
         $custom_map[$builtin_key] = $key;
       }
     }
 
     $builtin_uris = $this->newBuiltinURIs();
     $seen_builtins = array();
     foreach ($builtin_uris as $builtin_uri) {
       $builtin_key = $builtin_uri->getRepositoryURIBuiltinKey();
       $seen_builtins[$builtin_key] = true;
 
       // If this builtin URI is disabled, don't attach it and remove the
       // persisted version if it exists.
       if ($builtin_uri->getIsDisabled()) {
         if (isset($custom_map[$builtin_key])) {
           unset($uris[$custom_map[$builtin_key]]);
         }
         continue;
       }
 
       // If the URI exists, make sure it's marked as not being disabled.
       if (isset($custom_map[$builtin_key])) {
         $uris[$custom_map[$builtin_key]]->setIsDisabled(false);
       }
     }
 
     // Remove any builtins which no longer exist.
     foreach ($custom_map as $builtin_key => $key) {
       if (empty($seen_builtins[$builtin_key])) {
         unset($uris[$key]);
       }
     }
 
     $this->uris = $uris;
 
     return $this;
   }
 
   public function getURIs() {
     return $this->assertAttached($this->uris);
   }
 
   public function getCloneURIs() {
     $uris = $this->getURIs();
 
     $clone = array();
     foreach ($uris as $uri) {
       if (!$uri->isBuiltin()) {
         continue;
       }
 
       if ($uri->getIsDisabled()) {
         continue;
       }
 
       $io_type = $uri->getEffectiveIoType();
       $is_clone =
         ($io_type == PhabricatorRepositoryURI::IO_READ) ||
         ($io_type == PhabricatorRepositoryURI::IO_READWRITE);
 
       if (!$is_clone) {
         continue;
       }
 
       $clone[] = $uri;
     }
 
     $clone = msort($clone, 'getURIScore');
     $clone = array_reverse($clone);
 
     return $clone;
   }
 
 
   public function newBuiltinURIs() {
     $has_callsign = ($this->getCallsign() !== null);
     $has_shortname = ($this->getRepositorySlug() !== null);
 
     $identifier_map = array(
       PhabricatorRepositoryURI::BUILTIN_IDENTIFIER_CALLSIGN => $has_callsign,
       PhabricatorRepositoryURI::BUILTIN_IDENTIFIER_SHORTNAME => $has_shortname,
       PhabricatorRepositoryURI::BUILTIN_IDENTIFIER_ID => true,
     );
 
     // If the view policy of the repository is public, support anonymous HTTP
     // even if authenticated HTTP is not supported.
     if ($this->getViewPolicy() === PhabricatorPolicies::POLICY_PUBLIC) {
       $allow_http = true;
     } else {
       $allow_http = PhabricatorEnv::getEnvConfig('diffusion.allow-http-auth');
     }
 
     $base_uri = PhabricatorEnv::getURI('/');
     $base_uri = new PhutilURI($base_uri);
     $has_https = ($base_uri->getProtocol() == 'https');
     $has_https = ($has_https && $allow_http);
 
     $has_http = !PhabricatorEnv::getEnvConfig('security.require-https');
     $has_http = ($has_http && $allow_http);
 
     // HTTP is not supported for Subversion.
     if ($this->isSVN()) {
       $has_http = false;
       $has_https = false;
     }
 
     $has_ssh = (bool)strlen(PhabricatorEnv::getEnvConfig('phd.user'));
 
     $protocol_map = array(
       PhabricatorRepositoryURI::BUILTIN_PROTOCOL_SSH => $has_ssh,
       PhabricatorRepositoryURI::BUILTIN_PROTOCOL_HTTPS => $has_https,
       PhabricatorRepositoryURI::BUILTIN_PROTOCOL_HTTP => $has_http,
     );
 
     $uris = array();
     foreach ($protocol_map as $protocol => $proto_supported) {
       foreach ($identifier_map as $identifier => $id_supported) {
         // This is just a dummy value because it can't be empty; we'll force
         // it to a proper value when using it in the UI.
         $builtin_uri = "{$protocol}://{$identifier}";
         $uris[] = PhabricatorRepositoryURI::initializeNewURI()
           ->setRepositoryPHID($this->getPHID())
           ->attachRepository($this)
           ->setBuiltinProtocol($protocol)
           ->setBuiltinIdentifier($identifier)
           ->setURI($builtin_uri)
           ->setIsDisabled((int)(!$proto_supported || !$id_supported));
       }
     }
 
     return $uris;
   }
 
 
   public function getClusterRepositoryURIFromBinding(
     AlmanacBinding $binding) {
     $protocol = $binding->getAlmanacPropertyValue('protocol');
     if ($protocol === null) {
       $protocol = 'https';
     }
 
     $iface = $binding->getInterface();
     $address = $iface->renderDisplayAddress();
 
     $path = $this->getURI();
 
     return id(new PhutilURI("{$protocol}://{$address}"))
       ->setPath($path);
   }
 
   public function loadAlmanacService() {
     $service_phid = $this->getAlmanacServicePHID();
     if (!$service_phid) {
       // No service, so this is a local repository.
       return null;
     }
 
     $service = id(new AlmanacServiceQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withPHIDs(array($service_phid))
       ->needBindings(true)
       ->needProperties(true)
       ->executeOne();
     if (!$service) {
       throw new Exception(
         pht(
           'The Almanac service for this repository is invalid or could not '.
           'be loaded.'));
     }
 
     $service_type = $service->getServiceImplementation();
     if (!($service_type instanceof AlmanacClusterRepositoryServiceType)) {
       throw new Exception(
         pht(
           'The Almanac service for this repository does not have the correct '.
           'service type.'));
     }
 
     return $service;
   }
 
   public function markImporting() {
     $this->openTransaction();
       $this->beginReadLocking();
         $repository = $this->reload();
         $repository->setDetail('importing', true);
         $repository->save();
       $this->endReadLocking();
     $this->saveTransaction();
 
     return $repository;
   }
 
 
 /* -(  Symbols  )-------------------------------------------------------------*/
 
   public function getSymbolSources() {
     return $this->getDetail('symbol-sources', array());
   }
 
   public function getSymbolLanguages() {
     return $this->getDetail('symbol-languages', array());
   }
 
 
 /* -(  Staging  )------------------------------------------------------------ */
 
 
   public function supportsStaging() {
     return $this->isGit();
   }
 
 
   public function getStagingURI() {
     if (!$this->supportsStaging()) {
       return null;
     }
     return $this->getDetail('staging-uri', null);
   }
 
 
 /* -(  Automation  )--------------------------------------------------------- */
 
 
   public function supportsAutomation() {
     return $this->isGit();
   }
 
   public function canPerformAutomation() {
     if (!$this->supportsAutomation()) {
       return false;
     }
 
     if (!$this->getAutomationBlueprintPHIDs()) {
       return false;
     }
 
     return true;
   }
 
   public function getAutomationBlueprintPHIDs() {
     if (!$this->supportsAutomation()) {
       return array();
     }
     return $this->getDetail('automation.blueprintPHIDs', array());
   }
 
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */
 
 
   public function getApplicationTransactionEditor() {
     return new PhabricatorRepositoryEditor();
   }
 
   public function getApplicationTransactionObject() {
     return $this;
   }
 
   public function getApplicationTransactionTemplate() {
     return new PhabricatorRepositoryTransaction();
   }
 
   public function willRenderTimeline(
     PhabricatorApplicationTransactionView $timeline,
     AphrontRequest $request) {
 
     return $timeline;
   }
 
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
 
   public function getCapabilities() {
     return array(
       PhabricatorPolicyCapability::CAN_VIEW,
       PhabricatorPolicyCapability::CAN_EDIT,
       DiffusionPushCapability::CAPABILITY,
     );
   }
 
   public function getPolicy($capability) {
     switch ($capability) {
       case PhabricatorPolicyCapability::CAN_VIEW:
         return $this->getViewPolicy();
       case PhabricatorPolicyCapability::CAN_EDIT:
         return $this->getEditPolicy();
       case DiffusionPushCapability::CAPABILITY:
         return $this->getPushPolicy();
     }
   }
 
   public function hasAutomaticCapability($capability, PhabricatorUser $user) {
     return false;
   }
 
 
 /* -(  PhabricatorMarkupInterface  )----------------------------------------- */
 
 
   public function getMarkupFieldKey($field) {
     $hash = PhabricatorHash::digestForIndex($this->getMarkupText($field));
     return "repo:{$hash}";
   }
 
   public function newMarkupEngine($field) {
     return PhabricatorMarkupEngine::newMarkupEngine(array());
   }
 
   public function getMarkupText($field) {
     return $this->getDetail('description');
   }
 
   public function didMarkupText(
     $field,
     $output,
     PhutilMarkupEngine $engine) {
     require_celerity_resource('phabricator-remarkup-css');
     return phutil_tag(
       'div',
       array(
         'class' => 'phabricator-remarkup',
       ),
       $output);
   }
 
   public function shouldUseMarkupCache($field) {
     return true;
   }
 
 
 /* -(  PhabricatorDestructibleInterface  )----------------------------------- */
 
 
   public function destroyObjectPermanently(
     PhabricatorDestructionEngine $engine) {
 
     $phid = $this->getPHID();
 
     $this->openTransaction();
 
       $this->delete();
 
       PhabricatorRepositoryURIIndex::updateRepositoryURIs($phid, array());
 
       $books = id(new DivinerBookQuery())
         ->setViewer($engine->getViewer())
         ->withRepositoryPHIDs(array($phid))
         ->execute();
       foreach ($books as $book) {
         $engine->destroyObject($book);
       }
 
       $atoms = id(new DivinerAtomQuery())
         ->setViewer($engine->getViewer())
         ->withRepositoryPHIDs(array($phid))
         ->execute();
       foreach ($atoms as $atom) {
         $engine->destroyObject($atom);
       }
 
       $lfs_refs = id(new PhabricatorRepositoryGitLFSRefQuery())
         ->setViewer($engine->getViewer())
         ->withRepositoryPHIDs(array($phid))
         ->execute();
       foreach ($lfs_refs as $ref) {
         $engine->destroyObject($ref);
       }
 
     $this->saveTransaction();
   }
 
 
 /* -(  PhabricatorDestructibleCodexInterface  )------------------------------ */
 
 
   public function newDestructibleCodex() {
     return new PhabricatorRepositoryDestructibleCodex();
   }
 
 
 /* -(  PhabricatorSpacesInterface  )----------------------------------------- */
 
 
   public function getSpacePHID() {
     return $this->spacePHID;
   }
 
 /* -(  PhabricatorConduitResultInterface  )---------------------------------- */
 
 
   public function getFieldSpecificationsForConduit() {
     return array(
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('name')
         ->setType('string')
         ->setDescription(pht('The repository name.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('vcs')
         ->setType('string')
         ->setDescription(
           pht('The VCS this repository uses ("git", "hg" or "svn").')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('callsign')
         ->setType('string')
         ->setDescription(pht('The repository callsign, if it has one.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('shortName')
         ->setType('string')
         ->setDescription(pht('Unique short name, if the repository has one.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('status')
         ->setType('string')
         ->setDescription(pht('Active or inactive status.')),
       id(new PhabricatorConduitSearchFieldSpecification())
         ->setKey('isImporting')
         ->setType('bool')
         ->setDescription(
           pht(
             'True if the repository is importing initial commits.')),
     );
   }
 
   public function getFieldValuesForConduit() {
     return array(
       'name' => $this->getName(),
       'vcs' => $this->getVersionControlSystem(),
       'callsign' => $this->getCallsign(),
       'shortName' => $this->getRepositorySlug(),
       'status' => $this->getStatus(),
       'isImporting' => (bool)$this->isImporting(),
     );
   }
 
   public function getConduitSearchAttachments() {
     return array(
       id(new DiffusionRepositoryURIsSearchEngineAttachment())
         ->setAttachmentKey('uris'),
     );
   }
 
 /* -(  PhabricatorFulltextInterface  )--------------------------------------- */
 
 
   public function newFulltextEngine() {
     return new PhabricatorRepositoryFulltextEngine();
   }
 
 
 /* -(  PhabricatorFerretInterface  )----------------------------------------- */
 
 
   public function newFerretEngine() {
     return new PhabricatorRepositoryFerretEngine();
   }
 
 }