diff --git a/resources/sql/autopatches/20141222.maniphestprojtxn.php b/resources/sql/autopatches/20141222.maniphestprojtxn.php
--- a/resources/sql/autopatches/20141222.maniphestprojtxn.php
+++ b/resources/sql/autopatches/20141222.maniphestprojtxn.php
@@ -9,41 +9,53 @@
   'edge:type' => PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
 );
 foreach (new LiskMigrationIterator($table) as $txn) {
-  // ManiphestTransaction::TYPE_PROJECTS
-  if ($txn->getTransactionType() == 'projects') {
-    $old_value = mig20141222_build_edge_data(
-      $txn->getOldValue(),
-      $txn->getObjectPHID());
-    $new_value = mig20141222_build_edge_data(
-      $txn->getNewvalue(),
-      $txn->getObjectPHID());
-    queryfx(
-      $conn_w,
-      'UPDATE %T SET '.
-        'transactionType = %s, oldValue = %s, newValue = %s, metaData = %s '.
-      'WHERE id = %d',
-      $table->getTableName(),
-      PhabricatorTransactions::TYPE_EDGE,
-      json_encode($old_value),
-      json_encode($new_value),
-      json_encode($metadata),
-      $txn->getID());
+  if ($txn->getTransactionType() != 'projects') {
+    continue;
   }
+
+  $old_value = mig20141222_build_edge_data(
+    $txn->getOldValue(),
+    $txn->getObjectPHID());
+
+  $new_value = mig20141222_build_edge_data(
+    $txn->getNewValue(),
+    $txn->getObjectPHID());
+
+  queryfx(
+    $conn_w,
+    'UPDATE %T SET '.
+      'transactionType = %s, oldValue = %s, newValue = %s, metaData = %s '.
+    'WHERE id = %d',
+    $table->getTableName(),
+    PhabricatorTransactions::TYPE_EDGE,
+    json_encode($old_value),
+    json_encode($new_value),
+    json_encode($metadata),
+    $txn->getID());
 }
 
 echo pht('Done.')."\n";
 
-function mig20141222_build_edge_data(array $project_phids, $task_phid) {
+function mig20141222_build_edge_data($project_phids, $task_phid) {
   $edge_data = array();
+
+  // See T9464. If we didn't get a proper array value out of the transaction,
+  // just return an empty value so we can move forward.
+  if (!is_array($project_phids)) {
+    return $edge_data;
+  }
+
   foreach ($project_phids as $project_phid) {
     if (!is_scalar($project_phid)) {
       continue;
     }
+
     $edge_data[$project_phid] = array(
       'src' => $task_phid,
       'type' => PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
       'dst' => $project_phid,
     );
   }
+
   return $edge_data;
 }