diff --git a/src/applications/differential/editor/DifferentialRevisionEditEngine.php b/src/applications/differential/editor/DifferentialRevisionEditEngine.php
index 07b693044f..9c399036d5 100644
--- a/src/applications/differential/editor/DifferentialRevisionEditEngine.php
+++ b/src/applications/differential/editor/DifferentialRevisionEditEngine.php
@@ -1,327 +1,353 @@
 <?php
 
 final class DifferentialRevisionEditEngine
   extends PhabricatorEditEngine {
 
   private $diff;
 
   const ENGINECONST = 'differential.revision';
 
   const ACTIONGROUP_REVIEW = 'review';
   const ACTIONGROUP_REVISION = 'revision';
 
   public function getEngineName() {
     return pht('Revisions');
   }
 
   public function getSummaryHeader() {
     return pht('Configure Revision Forms');
   }
 
   public function getSummaryText() {
     return pht(
       'Configure creation and editing revision forms in Differential.');
   }
 
   public function getEngineApplicationClass() {
     return 'PhabricatorDifferentialApplication';
   }
 
   public function isEngineConfigurable() {
     return false;
   }
 
   protected function newEditableObject() {
     $viewer = $this->getViewer();
     return DifferentialRevision::initializeNewRevision($viewer);
   }
 
   protected function newObjectQuery() {
     return id(new DifferentialRevisionQuery())
       ->needActiveDiffs(true)
       ->needReviewers(true)
       ->needReviewerAuthority(true);
   }
 
   protected function getObjectCreateTitleText($object) {
     return pht('Create New Revision');
   }
 
   protected function getObjectEditTitleText($object) {
     $monogram = $object->getMonogram();
     $title = $object->getTitle();
 
     $diff = $this->getDiff();
     if ($diff) {
       return pht('Update Revision %s: %s', $monogram, $title);
     } else {
       return pht('Edit Revision %s: %s', $monogram, $title);
     }
   }
 
   protected function getObjectEditShortText($object) {
     return $object->getMonogram();
   }
 
   protected function getObjectCreateShortText() {
     return pht('Create Revision');
   }
 
   protected function getObjectName() {
     return pht('Revision');
   }
 
   protected function getCommentViewButtonText($object) {
     if ($object->isDraft()) {
       return pht('Submit Quietly');
     }
 
     return parent::getCommentViewButtonText($object);
   }
 
   protected function getObjectViewURI($object) {
     return $object->getURI();
   }
 
   protected function getEditorURI() {
     return $this->getApplication()->getApplicationURI('revision/edit/');
   }
 
   public function setDiff(DifferentialDiff $diff) {
     $this->diff = $diff;
     return $this;
   }
 
   public function getDiff() {
     return $this->diff;
   }
 
   protected function newCommentActionGroups() {
     return array(
       id(new PhabricatorEditEngineCommentActionGroup())
         ->setKey(self::ACTIONGROUP_REVIEW)
         ->setLabel(pht('Review Actions')),
       id(new PhabricatorEditEngineCommentActionGroup())
         ->setKey(self::ACTIONGROUP_REVISION)
         ->setLabel(pht('Revision Actions')),
     );
   }
 
   protected function buildCustomEditFields($object) {
     $viewer = $this->getViewer();
 
     $plan_required = PhabricatorEnv::getEnvConfig(
       'differential.require-test-plan-field');
     $plan_enabled = $this->isCustomFieldEnabled(
       $object,
       'differential:test-plan');
 
     $diff = $this->getDiff();
     if ($diff) {
       $diff_phid = $diff->getPHID();
     } else {
       $diff_phid = null;
     }
 
     $is_create = $this->getIsCreate();
     $is_update = ($diff && !$is_create);
 
     $fields = array();
 
     $fields[] = id(new PhabricatorHandlesEditField())
       ->setKey(DifferentialRevisionUpdateTransaction::EDITKEY)
       ->setLabel(pht('Update Diff'))
       ->setDescription(pht('New diff to create or update the revision with.'))
       ->setConduitDescription(pht('Create or update a revision with a diff.'))
       ->setConduitTypeDescription(pht('PHID of the diff.'))
       ->setTransactionType(
         DifferentialRevisionUpdateTransaction::TRANSACTIONTYPE)
       ->setHandleParameterType(new AphrontPHIDListHTTPParameterType())
       ->setSingleValue($diff_phid)
       ->setIsFormField((bool)$diff)
       ->setIsReorderable(false)
       ->setIsDefaultable(false)
       ->setIsInvisible(true)
       ->setIsLockable(false);
 
     if ($is_update) {
       $fields[] = id(new PhabricatorInstructionsEditField())
         ->setKey('update.help')
         ->setValue(pht('Describe the updates you have made to the diff.'));
       $fields[] = id(new PhabricatorCommentEditField())
         ->setKey('update.comment')
         ->setLabel(pht('Comment'))
         ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
         ->setIsWebOnly(true)
         ->setDescription(pht('Comments providing context for the update.'));
       $fields[] = id(new PhabricatorSubmitEditField())
         ->setKey('update.submit')
         ->setValue($this->getObjectEditButtonText($object));
       $fields[] = id(new PhabricatorDividerEditField())
         ->setKey('update.note');
     }
 
     $fields[] = id(new PhabricatorTextEditField())
       ->setKey(DifferentialRevisionTitleTransaction::EDITKEY)
       ->setLabel(pht('Title'))
       ->setIsRequired(true)
       ->setTransactionType(
         DifferentialRevisionTitleTransaction::TRANSACTIONTYPE)
       ->setDescription(pht('The title of the revision.'))
       ->setConduitDescription(pht('Retitle the revision.'))
       ->setConduitTypeDescription(pht('New revision title.'))
       ->setValue($object->getTitle());
 
     $fields[] = id(new PhabricatorRemarkupEditField())
       ->setKey(DifferentialRevisionSummaryTransaction::EDITKEY)
       ->setLabel(pht('Summary'))
       ->setTransactionType(
         DifferentialRevisionSummaryTransaction::TRANSACTIONTYPE)
       ->setDescription(pht('The summary of the revision.'))
       ->setConduitDescription(pht('Change the revision summary.'))
       ->setConduitTypeDescription(pht('New revision summary.'))
       ->setValue($object->getSummary());
 
     if ($plan_enabled) {
       $fields[] = id(new PhabricatorRemarkupEditField())
         ->setKey(DifferentialRevisionTestPlanTransaction::EDITKEY)
         ->setLabel(pht('Test Plan'))
         ->setIsRequired($plan_required)
         ->setTransactionType(
           DifferentialRevisionTestPlanTransaction::TRANSACTIONTYPE)
         ->setDescription(
           pht('Actions performed to verify the behavior of the change.'))
         ->setConduitDescription(pht('Update the revision test plan.'))
         ->setConduitTypeDescription(pht('New test plan.'))
         ->setValue($object->getTestPlan());
     }
 
     $fields[] = id(new PhabricatorDatasourceEditField())
       ->setKey(DifferentialRevisionReviewersTransaction::EDITKEY)
       ->setLabel(pht('Reviewers'))
       ->setDatasource(new DifferentialReviewerDatasource())
       ->setUseEdgeTransactions(true)
       ->setTransactionType(
         DifferentialRevisionReviewersTransaction::TRANSACTIONTYPE)
       ->setCommentActionLabel(pht('Change Reviewers'))
       ->setDescription(pht('Reviewers for this revision.'))
       ->setConduitDescription(pht('Change the reviewers for this revision.'))
       ->setConduitTypeDescription(pht('New reviewers.'))
       ->setValue($object->getReviewerPHIDsForEdit());
 
     $fields[] = id(new PhabricatorDatasourceEditField())
       ->setKey('repositoryPHID')
       ->setLabel(pht('Repository'))
       ->setDatasource(new DiffusionRepositoryDatasource())
       ->setTransactionType(
         DifferentialRevisionRepositoryTransaction::TRANSACTIONTYPE)
       ->setDescription(pht('The repository the revision belongs to.'))
       ->setConduitDescription(pht('Change the repository for this revision.'))
       ->setConduitTypeDescription(pht('New repository.'))
       ->setSingleValue($object->getRepositoryPHID());
 
     // This is a little flimsy, but allows "Maniphest Tasks: ..." to continue
     // working properly in commit messages until we fully sort out T5873.
     $fields[] = id(new PhabricatorHandlesEditField())
       ->setKey('tasks')
       ->setUseEdgeTransactions(true)
       ->setIsFormField(false)
       ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
       ->setMetadataValue(
         'edge:type',
         DifferentialRevisionHasTaskEdgeType::EDGECONST)
       ->setDescription(pht('Tasks associated with this revision.'))
       ->setConduitDescription(pht('Change associated tasks.'))
       ->setConduitTypeDescription(pht('List of tasks.'))
       ->setValue(array());
 
+    $fields[] = id(new PhabricatorHandlesEditField())
+      ->setKey('parents')
+      ->setUseEdgeTransactions(true)
+      ->setIsFormField(false)
+      ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
+      ->setMetadataValue(
+        'edge:type',
+        DifferentialRevisionDependsOnRevisionEdgeType::EDGECONST)
+      ->setDescription(pht('Parent revisions of this revision.'))
+      ->setConduitDescription(pht('Change associated parent revisions.'))
+      ->setConduitTypeDescription(pht('List of revisions.'))
+      ->setValue(array());
+
+    $fields[] = id(new PhabricatorHandlesEditField())
+      ->setKey('children')
+      ->setUseEdgeTransactions(true)
+      ->setIsFormField(false)
+      ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
+      ->setMetadataValue(
+        'edge:type',
+        DifferentialRevisionDependedOnByRevisionEdgeType::EDGECONST)
+      ->setDescription(pht('Child revisions of this revision.'))
+      ->setConduitDescription(pht('Change associated child revisions.'))
+      ->setConduitTypeDescription(pht('List of revisions.'))
+      ->setValue(array());
+
     $actions = DifferentialRevisionActionTransaction::loadAllActions();
     $actions = msortv($actions, 'getRevisionActionOrderVector');
 
     foreach ($actions as $key => $action) {
       $fields[] = $action->newEditField($object, $viewer);
     }
 
     $fields[] = id(new PhabricatorBoolEditField())
       ->setKey('draft')
       ->setLabel(pht('Hold as Draft'))
       ->setIsFormField(false)
       ->setOptions(
         pht('Autosubmit Once Builds Finish'),
         pht('Hold as Draft'))
       ->setTransactionType(
         DifferentialRevisionHoldDraftTransaction::TRANSACTIONTYPE)
       ->setDescription(pht('Hold revision as as draft.'))
       ->setConduitDescription(
         pht(
           'Change autosubmission from draft state after builds finish.'))
       ->setConduitTypeDescription(pht('New "Hold as Draft" setting.'))
       ->setValue($object->getHoldAsDraft());
 
     return $fields;
   }
 
   private function isCustomFieldEnabled(DifferentialRevision $revision, $key) {
     $field_list = PhabricatorCustomField::getObjectFields(
       $revision,
       PhabricatorCustomField::ROLE_VIEW);
 
     $fields = $field_list->getFields();
     return isset($fields[$key]);
   }
 
   protected function newAutomaticCommentTransactions($object) {
     $viewer = $this->getViewer();
     $xactions = array();
 
     $inlines = DifferentialTransactionQuery::loadUnsubmittedInlineComments(
       $viewer,
       $object);
     $inlines = msort($inlines, 'getID');
 
     $editor = $object->getApplicationTransactionEditor()
       ->setActor($viewer);
 
     $query_template = id(new DifferentialDiffInlineCommentQuery())
       ->withRevisionPHIDs(array($object->getPHID()));
 
     $xactions = $editor->newAutomaticInlineTransactions(
       $object,
       $inlines,
       DifferentialTransaction::TYPE_INLINE,
       $query_template);
 
     return $xactions;
   }
 
   protected function newCommentPreviewContent($object, array $xactions) {
     $viewer = $this->getViewer();
     $type_inline = DifferentialTransaction::TYPE_INLINE;
 
     $inlines = array();
     foreach ($xactions as $xaction) {
       if ($xaction->getTransactionType() === $type_inline) {
         $inlines[] = $xaction->getComment();
       }
     }
 
     $content = array();
 
     if ($inlines) {
       $inline_preview = id(new PHUIDiffInlineCommentPreviewListView())
         ->setViewer($viewer)
         ->setInlineComments($inlines);
 
       $content[] = phutil_tag(
         'div',
         array(
           'id' => 'inline-comment-preview',
         ),
         $inline_preview);
     }
 
     return $content;
   }
 
 
 }