diff --git a/src/applications/differential/conduit/ConduitAPI_differential_updaterevision_Method.php b/src/applications/differential/conduit/ConduitAPI_differential_updaterevision_Method.php
index a18a60bb64..532c56c384 100644
--- a/src/applications/differential/conduit/ConduitAPI_differential_updaterevision_Method.php
+++ b/src/applications/differential/conduit/ConduitAPI_differential_updaterevision_Method.php
@@ -60,9 +60,9 @@ final class ConduitAPI_differential_updaterevision_Method
     $editor->setActor($request->getUser());
     $editor->setContentSource($content_source);
     $fields = $request->getValue('fields');
+    $editor->addDiff($diff, $request->getValue('message'));
     $editor->copyFieldsFromConduit($fields);
 
-    $editor->addDiff($diff, $request->getValue('message'));
     $editor->save();
 
     return array(
diff --git a/src/applications/differential/editor/DifferentialRevisionEditor.php b/src/applications/differential/editor/DifferentialRevisionEditor.php
index c334cdffd8..5b6d90beab 100644
--- a/src/applications/differential/editor/DifferentialRevisionEditor.php
+++ b/src/applications/differential/editor/DifferentialRevisionEditor.php
@@ -34,9 +34,9 @@ final class DifferentialRevisionEditor extends PhabricatorEditor {
 
     $editor = new DifferentialRevisionEditor($revision);
     $editor->setActor($actor);
+    $editor->addDiff($diff, null);
     $editor->copyFieldsFromConduit($fields);
 
-    $editor->addDiff($diff, null);
     $editor->save();
 
     return $revision;
@@ -48,19 +48,19 @@ final class DifferentialRevisionEditor extends PhabricatorEditor {
     $revision = $this->revision;
     $revision->loadRelationships();
 
-    $aux_fields = DifferentialFieldSelector::newSelector()
+    $all_fields = DifferentialFieldSelector::newSelector()
       ->getFieldSpecifications();
 
-    foreach ($aux_fields as $key => $aux_field) {
+    $aux_fields = array();
+    foreach ($all_fields as $aux_field) {
       $aux_field->setRevision($revision);
+      $aux_field->setDiff($this->diff);
       $aux_field->setUser($actor);
-      if (!$aux_field->shouldAppearOnCommitMessage()) {
-        unset($aux_fields[$key]);
+      if ($aux_field->shouldAppearOnCommitMessage()) {
+        $aux_fields[$aux_field->getCommitMessageKey()] = $aux_field;
       }
     }
 
-    $aux_fields = mpull($aux_fields, null, 'getCommitMessageKey');
-
     foreach ($fields as $field => $value) {
       if (empty($aux_fields[$field])) {
         throw new Exception(
@@ -73,8 +73,7 @@ final class DifferentialRevisionEditor extends PhabricatorEditor {
       $aux_field->validateField();
     }
 
-    $aux_fields = array_values($aux_fields);
-    $this->setAuxiliaryFields($aux_fields);
+    $this->setAuxiliaryFields($all_fields);
   }
 
   public function setAuxiliaryFields(array $auxiliary_fields) {
diff --git a/src/applications/differential/field/specification/DifferentialBranchFieldSpecification.php b/src/applications/differential/field/specification/DifferentialBranchFieldSpecification.php
index 86b1399df8..c2563cb2c3 100644
--- a/src/applications/differential/field/specification/DifferentialBranchFieldSpecification.php
+++ b/src/applications/differential/field/specification/DifferentialBranchFieldSpecification.php
@@ -46,4 +46,28 @@ final class DifferentialBranchFieldSpecification
     }
   }
 
+  public function didWriteRevision(DifferentialRevisionEditor $editor) {
+    $branch = $this->getDiff()->getBranch();
+    $match = null;
+    if (preg_match('/^T(\d+)/i', $branch, $match)) { // No $ to allow T123_demo.
+      list(, $task_id) = $match;
+      $task = id(new ManiphestTask())->load($task_id);
+      if ($task) {
+        id(new PhabricatorEdgeEditor())
+          ->setActor($this->getUser())
+          ->addEdge(
+            $this->getRevision()->getPHID(),
+            PhabricatorEdgeConfig::TYPE_DREV_HAS_RELATED_TASK,
+            $task->getPHID())
+          ->save();
+      }
+    }
+  }
+
+  public function getCommitMessageTips() {
+    return array(
+      'Name branch "T123" to attach the diff to a task.',
+    );
+  }
+
 }