diff --git a/src/applications/diffusion/data/DiffusionCommitHash.php b/src/applications/diffusion/data/DiffusionCommitHash.php
--- a/src/applications/diffusion/data/DiffusionCommitHash.php
+++ b/src/applications/diffusion/data/DiffusionCommitHash.php
@@ -23,4 +23,15 @@
     return $this->hashType;
   }
 
+  public static function convertArrayToObjects(array $hashes) {
+    $hash_objects = array();
+    foreach ($hashes as $hash) {
+      $type = $hash[0];
+      $hash = $hash[1];
+      $hash_objects[] = id(new DiffusionCommitHash())
+        ->setHashType($type)
+        ->setHashValue($hash);
+    }
+    return $hash_objects;
+  }
 }
diff --git a/src/applications/diffusion/query/lowlevel/DiffusionLowLevelCommitFieldsQuery.php b/src/applications/diffusion/query/lowlevel/DiffusionLowLevelCommitFieldsQuery.php
--- a/src/applications/diffusion/query/lowlevel/DiffusionLowLevelCommitFieldsQuery.php
+++ b/src/applications/diffusion/query/lowlevel/DiffusionLowLevelCommitFieldsQuery.php
@@ -71,6 +71,8 @@
         $revision = $this->pickBestRevision($revisions);
         $fields['revisionID'] = $revision->getID();
         $revision_hashes = $revision->getHashes();
+        $revision_hashes = DiffusionCommitHash::convertArrayToObjects(
+          $revision_hashes);
         $revision_hashes = mpull($revision_hashes, 'getHashType');
         // sort the hashes in the order the mighty
         // @{class:ArcanstDifferentialRevisionHash} does; probably unnecessary
@@ -79,7 +81,10 @@
           $revision_hashes,
           ArcanistDifferentialRevisionHash::getTypes());
         foreach ($hashes as $hash) {
-          $revision_hash = $revision_hashes[$hash->getHashType()];
+          $revision_hash = idx($revision_hashes, $hash->getHashType());
+          if (!$revision_hash) {
+            continue;
+          }
           if ($revision_hash->getHashValue() == $hash->getHashValue()) {
             $this->setRevisionMatchData(
               'matchHashType',