diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index 016d16721f69e0a37f781e7c87fd3e58f4e351b9..fa74a002a64044905310007cdcb6d4de3deec126 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -417,7 +417,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
     response = {
       title: merge_request.title,
-      sha: merge_request.diff_head_commit.short_id,
+      sha: (merge_request.diff_head_commit.short_id if merge_request.diff_head_sha),
       status: status,
       coverage: coverage
     }