diff --git a/src/applications/differential/application/PhabricatorDifferentialApplication.php b/src/applications/differential/application/PhabricatorDifferentialApplication.php
index a510bb8f26..be0ee46ac9 100644
--- a/src/applications/differential/application/PhabricatorDifferentialApplication.php
+++ b/src/applications/differential/application/PhabricatorDifferentialApplication.php
@@ -1,185 +1,189 @@
 <?php
 
 final class PhabricatorDifferentialApplication extends PhabricatorApplication {
 
   public function getBaseURI() {
     return '/differential/';
   }
 
   public function getName() {
     return pht('Differential');
   }
 
   public function getShortDescription() {
     return pht('Review Code');
   }
 
   public function getFontIcon() {
     return 'fa-cog';
   }
 
   public function isPinnedByDefault(PhabricatorUser $viewer) {
     return true;
   }
 
   public function getHelpURI() {
     return PhabricatorEnv::getDoclink('Differential User Guide');
   }
 
   public function getFactObjectsForAnalysis() {
     return array(
       new DifferentialRevision(),
     );
   }
 
   public function getTitleGlyph() {
     return "\xE2\x9A\x99";
   }
 
   public function getEventListeners() {
     return array(
       new DifferentialActionMenuEventListener(),
       new DifferentialHovercardEventListener(),
       new DifferentialLandingActionMenuEventListener(),
     );
   }
 
   public function getOverview() {
     return pht(<<<EOTEXT
 Differential is a **code review application** which allows engineers to review,
 discuss and approve changes to software.
 EOTEXT
 );
   }
 
   public function getRoutes() {
     return array(
       '/D(?P<id>[1-9]\d*)' => 'DifferentialRevisionViewController',
       '/differential/' => array(
         '(?:query/(?P<queryKey>[^/]+)/)?'
           => 'DifferentialRevisionListController',
         'diff/' => array(
           '(?P<id>[1-9]\d*)/' => 'DifferentialDiffViewController',
           'create/' => 'DifferentialDiffCreateController',
         ),
         'changeset/' => 'DifferentialChangesetViewController',
-        'revision/edit/(?:(?P<id>[1-9]\d*)/)?'
-          => 'DifferentialRevisionEditController',
-        'revision/land/(?:(?P<id>[1-9]\d*))/(?P<strategy>[^/]+)/'
-          => 'DifferentialRevisionLandController',
-        'revision/closedetails/(?P<phid>[^/]+)/'
-          => 'DifferentialRevisionCloseDetailsController',
+        'revision/' => array(
+          'edit/(?:(?P<id>[1-9]\d*)/)?'
+            => 'DifferentialRevisionEditController',
+          'land/(?:(?P<id>[1-9]\d*))/(?P<strategy>[^/]+)/'
+            => 'DifferentialRevisionLandController',
+          'closedetails/(?P<phid>[^/]+)/'
+            => 'DifferentialRevisionCloseDetailsController',
+          'update/(?P<revisionID>[1-9]\d*)/'
+            => 'DifferentialDiffCreateController',
+        ),
         'comment/' => array(
           'preview/(?P<id>[1-9]\d*)/' => 'DifferentialCommentPreviewController',
           'save/(?P<id>[1-9]\d*)/' => 'DifferentialCommentSaveController',
           'inline/' => array(
             'preview/(?P<id>[1-9]\d*)/'
               => 'DifferentialInlineCommentPreviewController',
             'edit/(?P<id>[1-9]\d*)/'
               => 'DifferentialInlineCommentEditController',
           ),
         ),
         'preview/' => 'PhabricatorMarkupPreviewController',
       ),
     );
   }
 
   public function getApplicationOrder() {
     return 0.100;
   }
 
   public function getRemarkupRules() {
     return array(
       new DifferentialRemarkupRule(),
     );
   }
 
   public function loadStatus(PhabricatorUser $user) {
     $revisions = id(new DifferentialRevisionQuery())
       ->setViewer($user)
       ->withResponsibleUsers(array($user->getPHID()))
       ->withStatus(DifferentialRevisionQuery::STATUS_OPEN)
       ->needRelationships(true)
       ->setLimit(self::MAX_STATUS_ITEMS)
       ->execute();
 
     $status = array();
     if (count($revisions) == self::MAX_STATUS_ITEMS) {
       $all_count = count($revisions);
       $all_count_str = self::formatStatusCount(
         $all_count,
         '%s Active Reviews',
         '%d Active Review(s)');
       $type = PhabricatorApplicationStatusView::TYPE_WARNING;
       $status[] = id(new PhabricatorApplicationStatusView())
         ->setType($type)
         ->setText($all_count_str)
         ->setCount($all_count);
     } else {
       list($blocking, $active, $waiting) =
         DifferentialRevisionQuery::splitResponsible(
           $revisions,
           array($user->getPHID()));
 
       $blocking = count($blocking);
       $blocking_str = self::formatStatusCount(
         $blocking,
         '%s Reviews Blocking Others',
         '%d Review(s) Blocking Others');
       $type = PhabricatorApplicationStatusView::TYPE_NEEDS_ATTENTION;
       $status[] = id(new PhabricatorApplicationStatusView())
         ->setType($type)
         ->setText($blocking_str)
         ->setCount($blocking);
 
       $active = count($active);
       $active_str = self::formatStatusCount(
         $active,
         '%s Reviews Need Attention',
         '%d Review(s) Need Attention');
       $type = PhabricatorApplicationStatusView::TYPE_WARNING;
       $status[] = id(new PhabricatorApplicationStatusView())
         ->setType($type)
         ->setText($active_str)
         ->setCount($active);
 
       $waiting = count($waiting);
       $waiting_str = self::formatStatusCount(
         $waiting,
         '%s Reviews Waiting on Others',
         '%d Review(s) Waiting on Others');
       $type = PhabricatorApplicationStatusView::TYPE_INFO;
       $status[] = id(new PhabricatorApplicationStatusView())
         ->setType($type)
         ->setText($waiting_str)
         ->setCount($waiting);
     }
 
     return $status;
   }
 
   public function supportsEmailIntegration() {
     return true;
   }
 
   public function getAppEmailBlurb() {
     return pht(
       'Send email to these addresses to create revisions. The body of the '.
       'message and / or one or more attachments should be the output of a '.
       '"diff" command. %s',
       phutil_tag(
         'a',
         array(
           'href' => $this->getInboundEmailSupportLink(),),
         pht('Learn More')));
   }
 
   protected function getCustomCapabilities() {
     return array(
       DifferentialDefaultViewCapability::CAPABILITY => array(
         'caption' => pht('Default view policy for newly created revisions.'),
       ),
     );
   }
 
 }
diff --git a/src/applications/differential/controller/DifferentialController.php b/src/applications/differential/controller/DifferentialController.php
index 964f989ae5..30e8c92d39 100644
--- a/src/applications/differential/controller/DifferentialController.php
+++ b/src/applications/differential/controller/DifferentialController.php
@@ -1,36 +1,24 @@
 <?php
 
 abstract class DifferentialController extends PhabricatorController {
 
-  protected function buildApplicationCrumbs() {
-    $crumbs = parent::buildApplicationCrumbs();
-
-    $crumbs->addAction(
-      id(new PHUIListItemView())
-        ->setHref($this->getApplicationURI('/diff/create/'))
-        ->setName(pht('Create Diff'))
-        ->setIcon('fa-plus-square'));
-
-    return $crumbs;
-  }
-
   public function buildSideNavView($for_app = false) {
     $viewer = $this->getRequest()->getUser();
 
     $nav = new AphrontSideNavFilterView();
     $nav->setBaseURI(new PhutilURI($this->getApplicationURI()));
 
     id(new DifferentialRevisionSearchEngine())
       ->setViewer($viewer)
       ->addNavigationItems($nav->getMenu());
 
     $nav->selectFilter(null);
 
     return $nav;
   }
 
   public function buildApplicationMenu() {
     return $this->buildSideNavView(true)->getMenu();
   }
 
 }
diff --git a/src/applications/differential/controller/DifferentialDiffCreateController.php b/src/applications/differential/controller/DifferentialDiffCreateController.php
index 9c3698e3f2..e23f6cf718 100644
--- a/src/applications/differential/controller/DifferentialDiffCreateController.php
+++ b/src/applications/differential/controller/DifferentialDiffCreateController.php
@@ -1,143 +1,211 @@
 <?php
 
 final class DifferentialDiffCreateController extends DifferentialController {
 
-  public function processRequest() {
-
-    $request = $this->getRequest();
-    $viewer = $request->getUser();
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $this->getViewer();
+
+    // If we're on the "Update Diff" workflow, load the revision we're going
+    // to update.
+    $revision = null;
+    $revision_id = $request->getURIData('revisionID');
+    if ($revision_id) {
+      $revision = id(new DifferentialRevisionQuery())
+        ->setViewer($viewer)
+        ->withIDs(array($revision_id))
+        ->requireCapabilities(
+          array(
+            PhabricatorPolicyCapability::CAN_VIEW,
+            PhabricatorPolicyCapability::CAN_EDIT,
+          ))
+        ->executeOne();
+      if (!$revision) {
+        return new Aphront404Response();
+      }
+    }
 
     $diff = null;
     // This object is just for policy stuff
     $diff_object = DifferentialDiff::initializeNewDiff($viewer);
     $repository_phid = null;
     $repository_value = array();
     $errors = array();
     $e_diff = null;
     $e_file = null;
     $validation_exception = null;
     if ($request->isFormPost()) {
 
       $repository_tokenizer = $request->getArr(
         id(new DifferentialRepositoryField())->getFieldKey());
       if ($repository_tokenizer) {
         $repository_phid = reset($repository_tokenizer);
       }
 
       if ($request->getFileExists('diff-file')) {
         $diff = PhabricatorFile::readUploadedFileData($_FILES['diff-file']);
       } else {
         $diff = $request->getStr('diff');
       }
 
       if (!strlen($diff)) {
         $errors[] = pht(
-          'You can not create an empty diff. Copy/paste a diff, or upload a '.
-          'diff file.');
+          'You can not create an empty diff. Paste a diff or upload a '.
+          'file containing a diff.');
         $e_diff = pht('Required');
         $e_file = pht('Required');
       }
 
       if (!$errors) {
         try {
           $call = new ConduitCall(
             'differential.createrawdiff',
             array(
               'diff' => $diff,
               'repositoryPHID' => $repository_phid,
               'viewPolicy' => $request->getStr('viewPolicy'),));
           $call->setUser($viewer);
           $result = $call->execute();
-          $path = id(new PhutilURI($result['uri']))->getPath();
-          return id(new AphrontRedirectResponse())->setURI($path);
+
+          $diff_id = $result['id'];
+
+          $uri = $this->getApplicationURI("diff/{$diff_id}/");
+          $uri = new PhutilURI($uri);
+          if ($revision) {
+            $uri->setQueryParam('revisionID', $revision->getID());
+          }
+
+          return id(new AphrontRedirectResponse())->setURI($uri);
         } catch (PhabricatorApplicationTransactionValidationException $ex) {
           $validation_exception = $ex;
         }
       }
     }
 
     $form = new AphrontFormView();
     $arcanist_href = PhabricatorEnv::getDoclink('Arcanist User Guide');
     $arcanist_link = phutil_tag(
       'a',
       array(
         'href' => $arcanist_href,
         'target' => '_blank',
       ),
-      'Arcanist');
+      'Learn More');
 
     $cancel_uri = $this->getApplicationURI();
 
     if ($repository_phid) {
       $repository_value = $this->loadViewerHandles(array($repository_phid));
     }
 
     $policies = id(new PhabricatorPolicyQuery())
       ->setViewer($viewer)
       ->setObject($diff_object)
       ->execute();
 
+    $info_view = null;
+    if (!$request->isFormPost()) {
+      $info_view = id(new PHUIInfoView())
+        ->setSeverity(PHUIInfoView::SEVERITY_NOTICE)
+        ->setErrors(
+          array(
+            array(
+              pht(
+                'The best way to create a diff is to use the Arcanist '.
+                'command-line tool.'),
+              ' ',
+              $arcanist_link,
+            ),
+            pht(
+              'You can also paste a diff below, or upload a file '.
+              'containing a diff (for example, from %s, %s or %s).',
+              phutil_tag('tt', array(), 'svn diff'),
+              phutil_tag('tt', array(), 'git diff'),
+              phutil_tag('tt', array(), 'hg diff --git')),
+          ));
+    }
+
+    if ($revision) {
+      $title = pht('Update Diff');
+      $header = pht('Update Diff');
+      $button = pht('Continue');
+    } else {
+      $title = pht('Create Diff');
+      $header = pht('Create New Diff');
+      $button = pht('Create Diff');
+    }
+
     $form
-      ->setAction('/differential/diff/create/')
       ->setEncType('multipart/form-data')
-      ->setUser($viewer)
-      ->appendInstructions(
-        pht(
-          'The best way to create a Differential diff is by using %s, but you '.
-          'can also just paste a diff (for example, from %s, %s or %s) into '.
-          'this box, or upload a diff file.',
-          $arcanist_link,
-          phutil_tag('tt', array(), 'svn diff'),
-          phutil_tag('tt', array(), 'git diff'),
-          phutil_tag('tt', array(), 'hg diff --git')))
+      ->setUser($viewer);
+
+    if ($revision) {
+      $revision_handles = $this->loadViewerHandles(array($revision->getPHID()));
+      $revision_handle = head($revision_handles);
+
+      $form->appendChild(
+        id(new AphrontFormMarkupControl())
+          ->setLabel(pht('Updating Revision'))
+          ->setValue($revision_handle->renderLink()));
+    }
+
+    $form
       ->appendChild(
         id(new AphrontFormTextAreaControl())
           ->setLabel(pht('Raw Diff'))
           ->setName('diff')
           ->setValue($diff)
           ->setHeight(AphrontFormTextAreaControl::HEIGHT_VERY_TALL)
           ->setError($e_diff))
       ->appendChild(
         id(new AphrontFormFileControl())
           ->setLabel(pht('Raw Diff From File'))
           ->setName('diff-file')
           ->setError($e_file))
       ->appendChild(
         id(new AphrontFormTokenizerControl())
         ->setName(id(new DifferentialRepositoryField())->getFieldKey())
         ->setLabel(pht('Repository'))
         ->setDatasource(new DiffusionRepositoryDatasource())
         ->setValue($repository_value)
         ->setLimit(1))
       ->appendChild(
         id(new AphrontFormPolicyControl())
         ->setUser($viewer)
         ->setName('viewPolicy')
         ->setPolicyObject($diff_object)
         ->setPolicies($policies)
         ->setCapability(PhabricatorPolicyCapability::CAN_VIEW))
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->addCancelButton($cancel_uri)
-          ->setValue(pht('Create Diff')));
+          ->setValue($button));
 
     $form_box = id(new PHUIObjectBoxView())
-      ->setHeaderText(pht('Create New Diff'))
+      ->setHeaderText($header)
       ->setValidationException($validation_exception)
       ->setForm($form)
       ->setFormErrors($errors);
 
+    if ($info_view) {
+      $form_box->setInfoView($info_view);
+    }
+
     $crumbs = $this->buildApplicationCrumbs();
-    $crumbs->addTextCrumb(pht('Create Diff'));
+    if ($revision) {
+      $crumbs->addTextCrumb(
+        $revision->getMonogram(),
+        '/'.$revision->getMonogram());
+    }
+    $crumbs->addTextCrumb($title);
 
     return $this->buildApplicationPage(
       array(
         $crumbs,
         $form_box,
       ),
       array(
-        'title' => pht('Create Diff'),
+        'title' => $title,
       ));
   }
 
 }
diff --git a/src/applications/differential/controller/DifferentialDiffViewController.php b/src/applications/differential/controller/DifferentialDiffViewController.php
index d521c54385..419e6d9ce9 100644
--- a/src/applications/differential/controller/DifferentialDiffViewController.php
+++ b/src/applications/differential/controller/DifferentialDiffViewController.php
@@ -1,146 +1,156 @@
 <?php
 
 final class DifferentialDiffViewController extends DifferentialController {
 
   private $id;
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function willProcessRequest(array $data) {
     $this->id = $data['id'];
   }
 
   public function processRequest() {
     $request = $this->getRequest();
     $viewer = $request->getUser();
 
     $diff = id(new DifferentialDiffQuery())
       ->setViewer($viewer)
       ->withIDs(array($this->id))
       ->executeOne();
     if (!$diff) {
       return new Aphront404Response();
     }
 
     if ($diff->getRevisionID()) {
       return id(new AphrontRedirectResponse())
         ->setURI('/D'.$diff->getRevisionID().'?id='.$diff->getID());
     }
 
-    $error_view = id(new PHUIInfoView())
-        ->setSeverity(PHUIInfoView::SEVERITY_NOTICE);
     // TODO: implement optgroup support in AphrontFormSelectControl?
     $select = array();
     $select[] = hsprintf('<optgroup label="%s">', pht('Create New Revision'));
     $select[] = phutil_tag(
       'option',
       array('value' => ''),
       pht('Create a new Revision...'));
     $select[] = hsprintf('</optgroup>');
 
     $revisions = id(new DifferentialRevisionQuery())
       ->setViewer($viewer)
       ->withAuthors(array($viewer->getPHID()))
       ->withStatus(DifferentialRevisionQuery::STATUS_OPEN)
+      ->requireCapabilities(
+        array(
+          PhabricatorPolicyCapability::CAN_VIEW,
+          PhabricatorPolicyCapability::CAN_EDIT,
+        ))
       ->execute();
 
+    $selected_id = $request->getInt('revisionID');
+
     if ($revisions) {
       $select[] = hsprintf(
         '<optgroup label="%s">',
         pht('Update Existing Revision'));
       foreach ($revisions as $revision) {
+        if ($selected_id == $revision->getID()) {
+          $selected = 'selected';
+        } else {
+          $selected = null;
+        }
+
         $select[] = phutil_tag(
           'option',
           array(
             'value' => $revision->getID(),
+            'selected' => $selected,
           ),
           id(new PhutilUTF8StringTruncator())
           ->setMaximumGlyphs(128)
           ->truncateString(
             'D'.$revision->getID().' '.$revision->getTitle()));
       }
       $select[] = hsprintf('</optgroup>');
     }
 
     $select = phutil_tag(
       'select',
       array('name' => 'revisionID'),
       $select);
 
     $form = id(new AphrontFormView())
       ->setUser($request->getUser())
       ->setAction('/differential/revision/edit/')
       ->addHiddenInput('diffID', $diff->getID())
       ->addHiddenInput('viaDiffView', 1)
       ->addHiddenInput(
         id(new DifferentialRepositoryField())->getFieldKey(),
         $diff->getRepositoryPHID())
       ->appendRemarkupInstructions(
         pht(
           'Review the diff for correctness. When you are satisfied, either '.
           '**create a new revision** or **update an existing revision**.'))
       ->appendChild(
         id(new AphrontFormMarkupControl())
         ->setLabel(pht('Attach To'))
         ->setValue($select))
       ->appendChild(
         id(new AphrontFormSubmitControl())
         ->setValue(pht('Continue')));
 
-    $error_view->appendChild($form);
-
     $props = id(new DifferentialDiffProperty())->loadAllWhere(
     'diffID = %d',
       $diff->getID());
     $props = mpull($props, 'getData', 'getName');
 
     $property_head = id(new PHUIHeaderView())
       ->setHeader(pht('Properties'));
 
     $property_view = new PHUIPropertyListView();
 
     $changesets = $diff->loadChangesets();
     $changesets = msort($changesets, 'getSortKey');
 
     $table_of_contents = id(new DifferentialDiffTableOfContentsView())
       ->setChangesets($changesets)
       ->setVisibleChangesets($changesets)
       ->setUnitTestData(idx($props, 'arc:unit', array()));
 
     $refs = array();
     foreach ($changesets as $changeset) {
       $refs[$changeset->getID()] = $changeset->getID();
     }
 
     $details = id(new DifferentialChangesetListView())
       ->setChangesets($changesets)
       ->setVisibleChangesets($changesets)
       ->setRenderingReferences($refs)
       ->setStandaloneURI('/differential/changeset/')
       ->setDiff($diff)
       ->setTitle(pht('Diff %d', $diff->getID()))
       ->setUser($request->getUser());
 
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->addTextCrumb(pht('Diff %d', $diff->getID()));
 
     $prop_box = id(new PHUIObjectBoxView())
       ->setHeader($property_head)
       ->addPropertyList($property_view)
-      ->setInfoView($error_view);
+      ->appendChild($form);
 
     return $this->buildApplicationPage(
       array(
         $crumbs,
         $prop_box,
         $table_of_contents,
         $details,
       ),
       array(
         'title' => pht('Diff View'),
       ));
   }
 
 }
diff --git a/src/applications/differential/controller/DifferentialRevisionListController.php b/src/applications/differential/controller/DifferentialRevisionListController.php
index bb6f13a5df..e48b088e6b 100644
--- a/src/applications/differential/controller/DifferentialRevisionListController.php
+++ b/src/applications/differential/controller/DifferentialRevisionListController.php
@@ -1,24 +1,36 @@
 <?php
 
 final class DifferentialRevisionListController extends DifferentialController {
 
   private $queryKey;
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function willProcessRequest(array $data) {
     $this->queryKey = idx($data, 'queryKey');
   }
 
   public function processRequest() {
     $controller = id(new PhabricatorApplicationSearchController())
       ->setQueryKey($this->queryKey)
       ->setSearchEngine(new DifferentialRevisionSearchEngine())
       ->setNavigation($this->buildSideNavView());
 
     return $this->delegateToController($controller);
   }
 
+  protected function buildApplicationCrumbs() {
+    $crumbs = parent::buildApplicationCrumbs();
+
+    $crumbs->addAction(
+      id(new PHUIListItemView())
+        ->setHref($this->getApplicationURI('/diff/create/'))
+        ->setName(pht('Create Diff'))
+        ->setIcon('fa-plus-square'));
+
+    return $crumbs;
+  }
+
 }
diff --git a/src/applications/differential/controller/DifferentialRevisionViewController.php b/src/applications/differential/controller/DifferentialRevisionViewController.php
index 940cd35b92..1b33b9bac8 100644
--- a/src/applications/differential/controller/DifferentialRevisionViewController.php
+++ b/src/applications/differential/controller/DifferentialRevisionViewController.php
@@ -1,937 +1,944 @@
 <?php
 
 final class DifferentialRevisionViewController extends DifferentialController {
 
   private $revisionID;
 
   public function shouldAllowPublic() {
     return true;
   }
 
   public function willProcessRequest(array $data) {
     $this->revisionID = $data['id'];
   }
 
   public function processRequest() {
 
     $request = $this->getRequest();
     $user = $request->getUser();
     $viewer_is_anonymous = !$user->isLoggedIn();
 
     $revision = id(new DifferentialRevisionQuery())
       ->withIDs(array($this->revisionID))
       ->setViewer($request->getUser())
       ->needRelationships(true)
       ->needReviewerStatus(true)
       ->needReviewerAuthority(true)
       ->executeOne();
 
     if (!$revision) {
       return new Aphront404Response();
     }
 
     $diffs = id(new DifferentialDiffQuery())
       ->setViewer($request->getUser())
       ->withRevisionIDs(array($this->revisionID))
       ->needArcanistProjects(true)
       ->execute();
     $diffs = array_reverse($diffs, $preserve_keys = true);
 
     if (!$diffs) {
       throw new Exception(
         'This revision has no diffs. Something has gone quite wrong.');
     }
 
     $revision->attachActiveDiff(last($diffs));
 
     $diff_vs = $request->getInt('vs');
 
     $target_id = $request->getInt('id');
     $target = idx($diffs, $target_id, end($diffs));
 
     $target_manual = $target;
     if (!$target_id) {
       foreach ($diffs as $diff) {
         if ($diff->getCreationMethod() != 'commit') {
           $target_manual = $diff;
         }
       }
     }
 
     if (empty($diffs[$diff_vs])) {
       $diff_vs = null;
     }
 
     $repository = null;
     $repository_phid = $target->getRepositoryPHID();
     if ($repository_phid) {
       if ($repository_phid == $revision->getRepositoryPHID()) {
         $repository = $revision->getRepository();
       } else {
         $repository = id(new PhabricatorRepositoryQuery())
           ->setViewer($user)
           ->withPHIDs(array($repository_phid))
           ->executeOne();
       }
     }
 
     list($changesets, $vs_map, $vs_changesets, $rendering_references) =
       $this->loadChangesetsAndVsMap(
         $target,
         idx($diffs, $diff_vs),
         $repository);
 
     if ($request->getExists('download')) {
       return $this->buildRawDiffResponse(
         $revision,
         $changesets,
         $vs_changesets,
         $vs_map,
         $repository);
     }
 
     $props = id(new DifferentialDiffProperty())->loadAllWhere(
       'diffID = %d',
       $target_manual->getID());
     $props = mpull($props, 'getData', 'getName');
 
     $all_changesets = $changesets;
     $inlines = $revision->loadInlineComments($all_changesets);
 
     $object_phids = array_merge(
       $revision->getReviewers(),
       $revision->getCCPHIDs(),
       $revision->loadCommitPHIDs(),
       array(
         $revision->getAuthorPHID(),
         $user->getPHID(),
       ));
 
     foreach ($revision->getAttached() as $type => $phids) {
       foreach ($phids as $phid => $info) {
         $object_phids[] = $phid;
       }
     }
 
     $field_list = PhabricatorCustomField::getObjectFields(
       $revision,
       PhabricatorCustomField::ROLE_VIEW);
 
     $field_list->setViewer($user);
     $field_list->readFieldsFromStorage($revision);
 
     $warning_handle_map = array();
     foreach ($field_list->getFields() as $key => $field) {
       $req = $field->getRequiredHandlePHIDsForRevisionHeaderWarnings();
       foreach ($req as $phid) {
         $warning_handle_map[$key][] = $phid;
         $object_phids[] = $phid;
       }
     }
 
     $handles = $this->loadViewerHandles($object_phids);
 
     $request_uri = $request->getRequestURI();
 
     $limit = 100;
     $large = $request->getStr('large');
     if (count($changesets) > $limit && !$large) {
       $count = count($changesets);
       $warning = new PHUIInfoView();
       $warning->setTitle('Very Large Diff');
       $warning->setSeverity(PHUIInfoView::SEVERITY_WARNING);
       $warning->appendChild(hsprintf(
         '%s <strong>%s</strong>',
         pht(
           'This diff is very large and affects %s files. '.
           'You may load each file individually or ',
           new PhutilNumber($count)),
         phutil_tag(
           'a',
           array(
             'class' => 'button grey',
             'href' => $request_uri
               ->alter('large', 'true')
               ->setFragment('toc'),
           ),
           pht('Show All Files Inline'))));
       $warning = $warning->render();
 
       $my_inlines = id(new DifferentialInlineCommentQuery())
         ->withDraftComments($user->getPHID(), $this->revisionID)
         ->execute();
 
       $visible_changesets = array();
       foreach ($inlines + $my_inlines as $inline) {
         $changeset_id = $inline->getChangesetID();
         if (isset($changesets[$changeset_id])) {
           $visible_changesets[$changeset_id] = $changesets[$changeset_id];
         }
       }
 
       if (!empty($props['arc:lint'])) {
         $changeset_paths = mpull($changesets, null, 'getFilename');
         foreach ($props['arc:lint'] as $lint) {
           $changeset = idx($changeset_paths, $lint['path']);
           if ($changeset) {
             $visible_changesets[$changeset->getID()] = $changeset;
           }
         }
       }
     } else {
       $warning = null;
       $visible_changesets = $changesets;
     }
 
 
     // TODO: This should be in a DiffQuery or similar.
     $need_props = array();
     foreach ($field_list->getFields() as $field) {
       foreach ($field->getRequiredDiffPropertiesForRevisionView() as $prop) {
         $need_props[$prop] = $prop;
       }
     }
 
     if ($need_props) {
       $prop_diff = $revision->getActiveDiff();
       $load_props = id(new DifferentialDiffProperty())->loadAllWhere(
         'diffID = %d AND name IN (%Ls)',
         $prop_diff->getID(),
         $need_props);
       $load_props = mpull($load_props, 'getData', 'getName');
       foreach ($need_props as $need) {
         $prop_diff->attachProperty($need, idx($load_props, $need));
       }
     }
 
     $commit_hashes = mpull($diffs, 'getSourceControlBaseRevision');
     $local_commits = idx($props, 'local:commits', array());
     foreach ($local_commits as $local_commit) {
       $commit_hashes[] = idx($local_commit, 'tree');
       $commit_hashes[] = idx($local_commit, 'local');
     }
     $commit_hashes = array_unique(array_filter($commit_hashes));
     if ($commit_hashes) {
       $commits_for_links = id(new DiffusionCommitQuery())
         ->setViewer($user)
         ->withIdentifiers($commit_hashes)
         ->execute();
       $commits_for_links = mpull(
         $commits_for_links,
         null,
         'getCommitIdentifier');
     } else {
       $commits_for_links = array();
     }
 
     $revision_detail = id(new DifferentialRevisionDetailView())
       ->setUser($user)
       ->setRevision($revision)
       ->setDiff(end($diffs))
       ->setCustomFields($field_list)
       ->setURI($request->getRequestURI());
 
     $actions = $this->getRevisionActions($revision);
 
     $whitespace = $request->getStr(
       'whitespace',
       DifferentialChangesetParser::WHITESPACE_IGNORE_MOST);
 
     $arc_project = $target->getArcanistProject();
     if ($arc_project) {
       list($symbol_indexes, $project_phids) = $this->buildSymbolIndexes(
         $arc_project,
         $visible_changesets);
     } else {
       $symbol_indexes = array();
       $project_phids = null;
     }
 
     $revision_detail->setActions($actions);
     $revision_detail->setUser($user);
 
     $revision_detail_box = $revision_detail->render();
 
     $revision_warnings = $this->buildRevisionWarnings(
       $revision,
       $field_list,
       $warning_handle_map,
       $handles);
     if ($revision_warnings) {
       $revision_warnings = id(new PHUIInfoView())
         ->setSeverity(PHUIInfoView::SEVERITY_WARNING)
         ->setErrors($revision_warnings);
       $revision_detail_box->setInfoView($revision_warnings);
     }
 
     $comment_view = $this->buildTransactions(
       $revision,
       $diff_vs ? $diffs[$diff_vs] : $target,
       $target,
       $all_changesets);
 
     if (!$viewer_is_anonymous) {
       $comment_view->setQuoteRef('D'.$revision->getID());
       $comment_view->setQuoteTargetID('comment-content');
     }
 
     $wrap_id = celerity_generate_unique_node_id();
     $comment_view = phutil_tag(
       'div',
       array(
         'id' => $wrap_id,
       ),
       $comment_view);
 
     if ($arc_project) {
       Javelin::initBehavior(
         'repository-crossreference',
         array(
           'section' => $wrap_id,
           'projects' => $project_phids,
         ));
     }
 
     $changeset_view = new DifferentialChangesetListView();
     $changeset_view->setChangesets($changesets);
     $changeset_view->setVisibleChangesets($visible_changesets);
 
     if (!$viewer_is_anonymous) {
       $changeset_view->setInlineCommentControllerURI(
         '/differential/comment/inline/edit/'.$revision->getID().'/');
     }
 
     $changeset_view->setStandaloneURI('/differential/changeset/');
     $changeset_view->setRawFileURIs(
       '/differential/changeset/?view=old',
       '/differential/changeset/?view=new');
 
     $changeset_view->setUser($user);
     $changeset_view->setDiff($target);
     $changeset_view->setRenderingReferences($rendering_references);
     $changeset_view->setVsMap($vs_map);
     $changeset_view->setWhitespace($whitespace);
     if ($repository) {
       $changeset_view->setRepository($repository);
     }
     $changeset_view->setSymbolIndexes($symbol_indexes);
     $changeset_view->setTitle('Diff '.$target->getID());
 
     $diff_history = id(new DifferentialRevisionUpdateHistoryView())
       ->setUser($user)
       ->setDiffs($diffs)
       ->setSelectedVersusDiffID($diff_vs)
       ->setSelectedDiffID($target->getID())
       ->setSelectedWhitespace($whitespace)
       ->setCommitsForLinks($commits_for_links);
 
     $local_view = id(new DifferentialLocalCommitsView())
       ->setUser($user)
       ->setLocalCommits(idx($props, 'local:commits'))
       ->setCommitsForLinks($commits_for_links);
 
     if ($repository) {
       $other_revisions = $this->loadOtherRevisions(
         $changesets,
         $target,
         $repository);
     } else {
       $other_revisions = array();
     }
 
     $other_view = null;
     if ($other_revisions) {
       $other_view = $this->renderOtherRevisions($other_revisions);
     }
 
     $toc_view = new DifferentialDiffTableOfContentsView();
     $toc_view->setChangesets($changesets);
     $toc_view->setVisibleChangesets($visible_changesets);
     $toc_view->setRenderingReferences($rendering_references);
     $toc_view->setUnitTestData(idx($props, 'arc:unit', array()));
     if ($repository) {
       $toc_view->setRepository($repository);
     }
     $toc_view->setDiff($target);
     $toc_view->setUser($user);
     $toc_view->setRevisionID($revision->getID());
     $toc_view->setWhitespace($whitespace);
 
     $comment_form = null;
     if (!$viewer_is_anonymous) {
       $draft = id(new PhabricatorDraft())->loadOneWhere(
         'authorPHID = %s AND draftKey = %s',
         $user->getPHID(),
         'differential-comment-'.$revision->getID());
 
       $reviewers = array();
       $ccs = array();
       if ($draft) {
         $reviewers = idx($draft->getMetadata(), 'reviewers', array());
         $ccs = idx($draft->getMetadata(), 'ccs', array());
         if ($reviewers || $ccs) {
           $handles = $this->loadViewerHandles(array_merge($reviewers, $ccs));
           $reviewers = array_select_keys($handles, $reviewers);
           $ccs = array_select_keys($handles, $ccs);
         }
       }
 
       $comment_form = new DifferentialAddCommentView();
       $comment_form->setRevision($revision);
 
       $review_warnings = array();
       foreach ($field_list->getFields() as $field) {
         $review_warnings[] = $field->getWarningsForDetailView();
       }
       $review_warnings = array_mergev($review_warnings);
 
       if ($review_warnings) {
         $review_warnings_panel = id(new PHUIInfoView())
           ->setSeverity(PHUIInfoView::SEVERITY_WARNING)
           ->setErrors($review_warnings);
         $comment_form->setInfoView($review_warnings_panel);
       }
 
       $comment_form->setActions($this->getRevisionCommentActions($revision));
       $action_uri = $this->getApplicationURI(
         'comment/save/'.$revision->getID().'/');
 
       $comment_form->setActionURI($action_uri);
       $comment_form->setUser($user);
       $comment_form->setDraft($draft);
       $comment_form->setReviewers(mpull($reviewers, 'getFullName', 'getPHID'));
       $comment_form->setCCs(mpull($ccs, 'getFullName', 'getPHID'));
 
       // TODO: This just makes the "Z" key work. Generalize this and remove
       // it at some point.
       $comment_form = phutil_tag(
         'div',
         array(
           'class' => 'differential-add-comment-panel',
         ),
         $comment_form);
     }
 
     $pane_id = celerity_generate_unique_node_id();
     Javelin::initBehavior(
       'differential-keyboard-navigation',
       array(
         'haunt' => $pane_id,
       ));
     Javelin::initBehavior('differential-user-select');
 
     $page_pane = id(new DifferentialPrimaryPaneView())
       ->setID($pane_id)
       ->appendChild($comment_view);
 
     $signatures = DifferentialRequiredSignaturesField::loadForRevision(
       $revision);
     $missing_signatures = false;
     foreach ($signatures as $phid => $signed) {
       if (!$signed) {
         $missing_signatures = true;
       }
     }
 
     if ($missing_signatures) {
       $signature_message = id(new PHUIInfoView())
         ->setErrors(
           array(
             array(
               phutil_tag('strong', array(), pht('Content Hidden:')),
               ' ',
               pht(
                 'The content of this revision is hidden until the author has '.
                 'signed all of the required legal agreements.'),
             ),
           ));
       $page_pane->appendChild($signature_message);
     } else {
       $page_pane->appendChild(
         array(
           $diff_history,
           $warning,
           $local_view,
           $toc_view,
           $other_view,
           $changeset_view,
         ));
     }
 
     if ($comment_form) {
       $page_pane->appendChild($comment_form);
     } else {
       // TODO: For now, just use this to get "Login to Comment".
       $page_pane->appendChild(
         id(new PhabricatorApplicationTransactionCommentView())
           ->setUser($user)
           ->setRequestURI($request->getRequestURI()));
     }
 
     $object_id = 'D'.$revision->getID();
 
     $content = array(
       $revision_detail_box,
       $page_pane,
     );
 
     $crumbs = $this->buildApplicationCrumbs();
     $crumbs->addTextCrumb($object_id, '/'.$object_id);
 
     $prefs = $user->loadPreferences();
 
     $pref_filetree = PhabricatorUserPreferences::PREFERENCE_DIFF_FILETREE;
     if ($prefs->getPreference($pref_filetree)) {
       $collapsed = $prefs->getPreference(
         PhabricatorUserPreferences::PREFERENCE_NAV_COLLAPSED,
         false);
 
       $nav = id(new DifferentialChangesetFileTreeSideNavBuilder())
         ->setTitle('D'.$revision->getID())
         ->setBaseURI(new PhutilURI('/D'.$revision->getID()))
         ->setCollapsed((bool)$collapsed)
         ->build($changesets);
       $nav->appendChild($content);
       $nav->setCrumbs($crumbs);
       $content = $nav;
     } else {
       array_unshift($content, $crumbs);
     }
 
     return $this->buildApplicationPage(
       $content,
       array(
         'title' => $object_id.' '.$revision->getTitle(),
         'pageObjects' => array($revision->getPHID()),
       ));
   }
 
   private function getRevisionActions(DifferentialRevision $revision) {
     $viewer = $this->getRequest()->getUser();
     $revision_id = $revision->getID();
     $revision_phid = $revision->getPHID();
 
     $can_edit = PhabricatorPolicyFilter::hasCapability(
       $viewer,
       $revision,
       PhabricatorPolicyCapability::CAN_EDIT);
 
     $actions = array();
 
     $actions[] = id(new PhabricatorActionView())
       ->setIcon('fa-pencil')
       ->setHref("/differential/revision/edit/{$revision_id}/")
       ->setName(pht('Edit Revision'))
       ->setDisabled(!$can_edit)
       ->setWorkflow(!$can_edit);
 
+    $actions[] = id(new PhabricatorActionView())
+      ->setIcon('fa-upload')
+      ->setHref("/differential/revision/update/{$revision_id}/")
+      ->setName(pht('Update Diff'))
+      ->setDisabled(!$can_edit)
+      ->setWorkflow(!$can_edit);
+
     $this->requireResource('phabricator-object-selector-css');
     $this->requireResource('javelin-behavior-phabricator-object-selector');
 
     $actions[] = id(new PhabricatorActionView())
       ->setIcon('fa-link')
       ->setName(pht('Edit Dependencies'))
       ->setHref("/search/attach/{$revision_phid}/DREV/dependencies/")
       ->setWorkflow(true)
       ->setDisabled(!$can_edit);
 
     $maniphest = 'PhabricatorManiphestApplication';
     if (PhabricatorApplication::isClassInstalled($maniphest)) {
       $actions[] = id(new PhabricatorActionView())
         ->setIcon('fa-anchor')
         ->setName(pht('Edit Maniphest Tasks'))
         ->setHref("/search/attach/{$revision_phid}/TASK/")
         ->setWorkflow(true)
         ->setDisabled(!$can_edit);
     }
 
     $request_uri = $this->getRequest()->getRequestURI();
     $actions[] = id(new PhabricatorActionView())
       ->setIcon('fa-download')
       ->setName(pht('Download Raw Diff'))
       ->setHref($request_uri->alter('download', 'true'));
 
     return $actions;
   }
 
   private function getRevisionCommentActions(DifferentialRevision $revision) {
     $actions = array(
       DifferentialAction::ACTION_COMMENT => true,
     );
 
     $viewer = $this->getRequest()->getUser();
     $viewer_phid = $viewer->getPHID();
     $viewer_is_owner = ($viewer_phid == $revision->getAuthorPHID());
     $viewer_is_reviewer = in_array($viewer_phid, $revision->getReviewers());
     $status = $revision->getStatus();
 
     $viewer_has_accepted = false;
     $viewer_has_rejected = false;
     $status_accepted = DifferentialReviewerStatus::STATUS_ACCEPTED;
     $status_rejected = DifferentialReviewerStatus::STATUS_REJECTED;
     foreach ($revision->getReviewerStatus() as $reviewer) {
       if ($reviewer->getReviewerPHID() == $viewer_phid) {
         if ($reviewer->getStatus() == $status_accepted) {
           $viewer_has_accepted = true;
         }
         if ($reviewer->getStatus() == $status_rejected) {
           $viewer_has_rejected = true;
         }
         break;
       }
     }
 
     $allow_self_accept = PhabricatorEnv::getEnvConfig(
       'differential.allow-self-accept');
     $always_allow_abandon = PhabricatorEnv::getEnvConfig(
       'differential.always-allow-abandon');
     $always_allow_close = PhabricatorEnv::getEnvConfig(
       'differential.always-allow-close');
     $allow_reopen = PhabricatorEnv::getEnvConfig(
       'differential.allow-reopen');
 
     if ($viewer_is_owner) {
       switch ($status) {
         case ArcanistDifferentialRevisionStatus::NEEDS_REVIEW:
           $actions[DifferentialAction::ACTION_ACCEPT] = $allow_self_accept;
           $actions[DifferentialAction::ACTION_ABANDON] = true;
           $actions[DifferentialAction::ACTION_RETHINK] = true;
           break;
         case ArcanistDifferentialRevisionStatus::NEEDS_REVISION:
         case ArcanistDifferentialRevisionStatus::CHANGES_PLANNED:
           $actions[DifferentialAction::ACTION_ACCEPT] = $allow_self_accept;
           $actions[DifferentialAction::ACTION_ABANDON] = true;
           $actions[DifferentialAction::ACTION_REQUEST] = true;
           break;
         case ArcanistDifferentialRevisionStatus::ACCEPTED:
           $actions[DifferentialAction::ACTION_ABANDON] = true;
           $actions[DifferentialAction::ACTION_REQUEST] = true;
           $actions[DifferentialAction::ACTION_RETHINK] = true;
           $actions[DifferentialAction::ACTION_CLOSE] = true;
           break;
         case ArcanistDifferentialRevisionStatus::CLOSED:
           break;
         case ArcanistDifferentialRevisionStatus::ABANDONED:
           $actions[DifferentialAction::ACTION_RECLAIM] = true;
           break;
       }
     } else {
       switch ($status) {
         case ArcanistDifferentialRevisionStatus::NEEDS_REVIEW:
           $actions[DifferentialAction::ACTION_ABANDON] = $always_allow_abandon;
           $actions[DifferentialAction::ACTION_ACCEPT] = true;
           $actions[DifferentialAction::ACTION_REJECT] = true;
           $actions[DifferentialAction::ACTION_RESIGN] = $viewer_is_reviewer;
           break;
         case ArcanistDifferentialRevisionStatus::NEEDS_REVISION:
         case ArcanistDifferentialRevisionStatus::CHANGES_PLANNED:
           $actions[DifferentialAction::ACTION_ABANDON] = $always_allow_abandon;
           $actions[DifferentialAction::ACTION_ACCEPT] = true;
           $actions[DifferentialAction::ACTION_REJECT] = !$viewer_has_rejected;
           $actions[DifferentialAction::ACTION_RESIGN] = $viewer_is_reviewer;
           break;
         case ArcanistDifferentialRevisionStatus::ACCEPTED:
           $actions[DifferentialAction::ACTION_ABANDON] = $always_allow_abandon;
           $actions[DifferentialAction::ACTION_ACCEPT] = !$viewer_has_accepted;
           $actions[DifferentialAction::ACTION_REJECT] = true;
           $actions[DifferentialAction::ACTION_RESIGN] = $viewer_is_reviewer;
           break;
         case ArcanistDifferentialRevisionStatus::CLOSED:
         case ArcanistDifferentialRevisionStatus::ABANDONED:
           break;
       }
       if ($status != ArcanistDifferentialRevisionStatus::CLOSED) {
         $actions[DifferentialAction::ACTION_CLAIM] = true;
         $actions[DifferentialAction::ACTION_CLOSE] = $always_allow_close;
       }
     }
 
     $actions[DifferentialAction::ACTION_ADDREVIEWERS] = true;
     $actions[DifferentialAction::ACTION_ADDCCS] = true;
     $actions[DifferentialAction::ACTION_REOPEN] = $allow_reopen &&
       ($status == ArcanistDifferentialRevisionStatus::CLOSED);
 
     $actions = array_keys(array_filter($actions));
     $actions_dict = array();
     foreach ($actions as $action) {
       $actions_dict[$action] = DifferentialAction::getActionVerb($action);
     }
 
     return $actions_dict;
   }
 
   private function loadChangesetsAndVsMap(
     DifferentialDiff $target,
     DifferentialDiff $diff_vs = null,
     PhabricatorRepository $repository = null) {
 
     $load_diffs = array($target);
     if ($diff_vs) {
       $load_diffs[] = $diff_vs;
     }
 
     $raw_changesets = id(new DifferentialChangesetQuery())
       ->setViewer($this->getRequest()->getUser())
       ->withDiffs($load_diffs)
       ->execute();
     $changeset_groups = mgroup($raw_changesets, 'getDiffID');
 
     $changesets = idx($changeset_groups, $target->getID(), array());
     $changesets = mpull($changesets, null, 'getID');
 
     $refs          = array();
     $vs_map        = array();
     $vs_changesets = array();
     if ($diff_vs) {
       $vs_id                  = $diff_vs->getID();
       $vs_changesets_path_map = array();
       foreach (idx($changeset_groups, $vs_id, array()) as $changeset) {
         $path = $changeset->getAbsoluteRepositoryPath($repository, $diff_vs);
         $vs_changesets_path_map[$path] = $changeset;
         $vs_changesets[$changeset->getID()] = $changeset;
       }
       foreach ($changesets as $key => $changeset) {
         $path = $changeset->getAbsoluteRepositoryPath($repository, $target);
         if (isset($vs_changesets_path_map[$path])) {
           $vs_map[$changeset->getID()] =
             $vs_changesets_path_map[$path]->getID();
           $refs[$changeset->getID()] =
             $changeset->getID().'/'.$vs_changesets_path_map[$path]->getID();
           unset($vs_changesets_path_map[$path]);
         } else {
           $refs[$changeset->getID()] = $changeset->getID();
         }
       }
       foreach ($vs_changesets_path_map as $path => $changeset) {
         $changesets[$changeset->getID()] = $changeset;
         $vs_map[$changeset->getID()]     = -1;
         $refs[$changeset->getID()]       = $changeset->getID().'/-1';
       }
     } else {
       foreach ($changesets as $changeset) {
         $refs[$changeset->getID()] = $changeset->getID();
       }
     }
 
     $changesets = msort($changesets, 'getSortKey');
 
     return array($changesets, $vs_map, $vs_changesets, $refs);
   }
 
   private function buildSymbolIndexes(
     PhabricatorRepositoryArcanistProject $arc_project,
     array $visible_changesets) {
     assert_instances_of($visible_changesets, 'DifferentialChangeset');
 
     $engine = PhabricatorSyntaxHighlighter::newEngine();
 
     $langs = $arc_project->getSymbolIndexLanguages();
     if (!$langs) {
       return array(array(), array());
     }
 
     $symbol_indexes = array();
 
     $project_phids = array_merge(
       array($arc_project->getPHID()),
       nonempty($arc_project->getSymbolIndexProjects(), array()));
 
     $indexed_langs = array_fill_keys($langs, true);
     foreach ($visible_changesets as $key => $changeset) {
       $lang = $engine->getLanguageFromFilename($changeset->getFilename());
       if (isset($indexed_langs[$lang])) {
         $symbol_indexes[$key] = array(
           'lang'      => $lang,
           'projects'  => $project_phids,
         );
       }
     }
 
     return array($symbol_indexes, $project_phids);
   }
 
   private function loadOtherRevisions(
     array $changesets,
     DifferentialDiff $target,
     PhabricatorRepository $repository) {
     assert_instances_of($changesets, 'DifferentialChangeset');
 
     $paths = array();
     foreach ($changesets as $changeset) {
       $paths[] = $changeset->getAbsoluteRepositoryPath(
         $repository,
         $target);
     }
 
     if (!$paths) {
       return array();
     }
 
     $path_map = id(new DiffusionPathIDQuery($paths))->loadPathIDs();
 
     if (!$path_map) {
       return array();
     }
 
     $query = id(new DifferentialRevisionQuery())
       ->setViewer($this->getRequest()->getUser())
       ->withStatus(DifferentialRevisionQuery::STATUS_OPEN)
       ->setOrder(DifferentialRevisionQuery::ORDER_PATH_MODIFIED)
       ->setLimit(10)
       ->needFlags(true)
       ->needDrafts(true)
       ->needRelationships(true);
 
     foreach ($path_map as $path => $path_id) {
       $query->withPath($repository->getID(), $path_id);
     }
 
     $results = $query->execute();
 
     // Strip out *this* revision.
     foreach ($results as $key => $result) {
       if ($result->getID() == $this->revisionID) {
         unset($results[$key]);
       }
     }
 
     return $results;
   }
 
   private function renderOtherRevisions(array $revisions) {
     assert_instances_of($revisions, 'DifferentialRevision');
 
     $user = $this->getRequest()->getUser();
 
     $view = id(new DifferentialRevisionListView())
       ->setHeader(pht('Open Revisions Affecting These Files'))
       ->setRevisions($revisions)
       ->setUser($user);
 
     $phids = $view->getRequiredHandlePHIDs();
     $handles = $this->loadViewerHandles($phids);
     $view->setHandles($handles);
 
     return $view;
   }
 
 
   /**
    * Note this code is somewhat similar to the buildPatch method in
    * @{class:DifferentialReviewRequestMail}.
    *
    * @return @{class:AphrontRedirectResponse}
    */
   private function buildRawDiffResponse(
     DifferentialRevision $revision,
     array $changesets,
     array $vs_changesets,
     array $vs_map,
     PhabricatorRepository $repository = null) {
 
     assert_instances_of($changesets,    'DifferentialChangeset');
     assert_instances_of($vs_changesets, 'DifferentialChangeset');
 
     $viewer = $this->getRequest()->getUser();
 
     id(new DifferentialHunkQuery())
       ->setViewer($viewer)
       ->withChangesets($changesets)
       ->needAttachToChangesets(true)
       ->execute();
 
     $diff = new DifferentialDiff();
     $diff->attachChangesets($changesets);
     $raw_changes = $diff->buildChangesList();
     $changes = array();
     foreach ($raw_changes as $changedict) {
       $changes[] = ArcanistDiffChange::newFromDictionary($changedict);
     }
 
     $loader = id(new PhabricatorFileBundleLoader())
       ->setViewer($viewer);
 
     $bundle = ArcanistBundle::newFromChanges($changes);
     $bundle->setLoadFileDataCallback(array($loader, 'loadFileData'));
 
     $vcs = $repository ? $repository->getVersionControlSystem() : null;
     switch ($vcs) {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
       case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
         $raw_diff = $bundle->toGitPatch();
         break;
       case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
       default:
         $raw_diff = $bundle->toUnifiedDiff();
         break;
     }
 
     $request_uri = $this->getRequest()->getRequestURI();
 
     // this ends up being something like
     //   D123.diff
     // or the verbose
     //   D123.vs123.id123.whitespaceignore-all.diff
     // lame but nice to include these options
     $file_name = ltrim($request_uri->getPath(), '/').'.';
     foreach ($request_uri->getQueryParams() as $key => $value) {
       if ($key == 'download') {
         continue;
       }
       $file_name .= $key.$value.'.';
     }
     $file_name .= 'diff';
 
     $file = PhabricatorFile::buildFromFileDataOrHash(
       $raw_diff,
       array(
         'name' => $file_name,
         'ttl' => (60 * 60 * 24),
         'viewPolicy' => PhabricatorPolicies::POLICY_NOONE,
       ));
 
     $unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
       $file->attachToObject($revision->getPHID());
     unset($unguarded);
 
     return $file->getRedirectResponse();
   }
 
   private function buildTransactions(
     DifferentialRevision $revision,
     DifferentialDiff $left_diff,
     DifferentialDiff $right_diff,
     array $changesets) {
 
     $timeline = $this->buildTransactionTimeline(
       $revision,
       new DifferentialTransactionQuery(),
       $engine = null,
       array(
         'left' => $left_diff->getID(),
         'right' => $right_diff->getID(),
       ));
 
     return $timeline;
   }
 
   private function buildRevisionWarnings(
     DifferentialRevision $revision,
     PhabricatorCustomFieldList $field_list,
     array $warning_handle_map,
     array $handles) {
 
     $warnings = array();
     foreach ($field_list->getFields() as $key => $field) {
       $phids = idx($warning_handle_map, $key, array());
       $field_handles = array_select_keys($handles, $phids);
       $field_warnings = $field->getWarningsForRevisionHeader($field_handles);
       foreach ($field_warnings as $warning) {
         $warnings[] = $warning;
       }
     }
 
     return $warnings;
   }
 
 }