Fix race condition between pipeline creation and MR diff_head_sha update

2 files changed, 6 insertions, 12 deletions

diff --git a/app/services/ci/create_pipeline_service.rb b/app/services/ci/create_pipeline_service.rb
index 8227a78a650..13baa63220d 100644
--- a/app/services/ci/create_pipeline_service.rb
+++ b/app/services/ci/create_pipeline_service.rb
@@ -63,13 +63,10 @@ module Ci
     private
 
     def update_merge_requests_head_pipeline
-      merge_requests = MergeRequest.where(source_branch: @pipeline.ref, source_project: @pipeline.project)
+      return unless pipeline.latest?
 
-      merge_requests = merge_requests.select do |mr|
-        mr.diff_head_sha == @pipeline.sha
-      end
-
-      MergeRequest.where(id: merge_requests).update_all(head_pipeline_id: @pipeline.id)
+      MergeRequest.where(source_project: @pipeline.project, source_branch: @pipeline.ref).
+        update_all(head_pipeline_id: @pipeline.id)
     end
 
     def skip_ci?
diff --git a/app/services/merge_requests/create_service.rb b/app/services/merge_requests/create_service.rb
index fbf171f705e..71d37797bb4 100644
--- a/app/services/merge_requests/create_service.rb
+++ b/app/services/merge_requests/create_service.rb
@@ -30,15 +30,12 @@ module MergeRequests
     def head_pipeline_for(merge_request)
       return unless merge_request.source_project
 
-      sha = merge_request.source_branch_head&.id
-
+      sha = merge_request.source_branch_sha
       return unless sha
 
-      pipelines =
-        Ci::Pipeline.where(ref: merge_request.source_branch, project_id: merge_request.source_project.id, sha: sha).
-        order(id: :desc)
+      pipelines = merge_request.source_project.pipelines.where(ref: merge_request.source_branch, sha: sha)
 
-      pipelines.first
+      pipelines.order(id: :desc).first
     end
   end
 end