diff --git a/src/applications/search/controller/PhabricatorSearchAttachController.php b/src/applications/search/controller/PhabricatorSearchAttachController.php
--- a/src/applications/search/controller/PhabricatorSearchAttachController.php
+++ b/src/applications/search/controller/PhabricatorSearchAttachController.php
@@ -57,33 +57,67 @@
       $phids = array_values($phids);
 
       if ($edge_type) {
-        if (!$object instanceof PhabricatorApplicationTransactionInterface) {
-          throw new Exception(
-            pht(
-              'Expected object ("%s") to implement interface "%s".',
-              get_class($object),
-              'PhabricatorApplicationTransactionInterface'));
+        if ($object instanceof PhabricatorRepositoryCommit) {
+          // TODO: Remove this entire branch of special cased grossness
+          // after T4896.
+
+          $old_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
+            $this->phid,
+            $edge_type);
+          $add_phids = $phids;
+          $rem_phids = array_diff($old_phids, $add_phids);
+
+          // Doing this correctly (in a way that writes edge transactions) would
+          // be a huge mess and we don't get the commit half of the transaction
+          // anyway until T4896, so just write the edges themselves and skip
+          // the transactions for now.
+
+          $editor = new PhabricatorEdgeEditor();
+          foreach ($add_phids as $phid) {
+            $editor->addEdge(
+              $object->getPHID(),
+              DiffusionCommitHasTaskEdgeType::EDGECONST,
+              $phid);
+          }
+
+          foreach ($rem_phids as $phid) {
+            $editor->removeEdge(
+              $object->getPHID(),
+              DiffusionCommitHasTaskEdgeType::EDGECONST,
+              $phid);
+          }
+
+          $editor->save();
+
+        } else {
+          if (!$object instanceof PhabricatorApplicationTransactionInterface) {
+            throw new Exception(
+              pht(
+                'Expected object ("%s") to implement interface "%s".',
+                get_class($object),
+                'PhabricatorApplicationTransactionInterface'));
+          }
+
+          $old_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
+            $this->phid,
+            $edge_type);
+          $add_phids = $phids;
+          $rem_phids = array_diff($old_phids, $add_phids);
+
+          $txn_editor = $object->getApplicationTransactionEditor()
+            ->setActor($user)
+            ->setContentSourceFromRequest($request);
+          $txn_template = $object->getApplicationTransactionTemplate()
+            ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
+            ->setMetadataValue('edge:type', $edge_type)
+            ->setNewValue(array(
+              '+' => array_fuse($add_phids),
+              '-' => array_fuse($rem_phids)));
+          $txn_editor->applyTransactions(
+            $object->getApplicationTransactionObject(),
+            array($txn_template));
         }
 
-        $old_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
-          $this->phid,
-          $edge_type);
-        $add_phids = $phids;
-        $rem_phids = array_diff($old_phids, $add_phids);
-
-        $txn_editor = $object->getApplicationTransactionEditor()
-          ->setActor($user)
-          ->setContentSourceFromRequest($request);
-        $txn_template = $object->getApplicationTransactionTemplate()
-          ->setTransactionType(PhabricatorTransactions::TYPE_EDGE)
-          ->setMetadataValue('edge:type', $edge_type)
-          ->setNewValue(array(
-            '+' => array_fuse($add_phids),
-            '-' => array_fuse($rem_phids)));
-        $txn_editor->applyTransactions(
-          $object->getApplicationTransactionObject(),
-          array($txn_template));
-
         return id(new AphrontReloadResponse())->setURI($handle->getURI());
       } else {
         return $this->performMerge($object, $handle, $phids);