Fix label links update on project transfer

1 files changed, 8 insertions, 3 deletions

diff --git a/app/services/labels/transfer_service.rb b/app/services/labels/transfer_service.rb
index 775efed48eb..9b7486cf53b 100644
--- a/app/services/labels/transfer_service.rb
+++ b/app/services/labels/transfer_service.rb
@@ -64,9 +64,14 @@ module Labels
     end
 
     def update_label_links(labels, old_label_id:, new_label_id:)
-      LabelLink.joins(:label)
-        .merge(labels)
-        .where(label_id: old_label_id)
+      # use 'labels' relation to get label_link ids only of issues/MRs
+      # in the project being transferred.
+      # IDs are fetched in a separate query because MySQL doesn't
+      # allow referring of 'label_links' table in UPDATE query:
+      # https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/62435068
+      link_ids = labels.pluck('label_links.id')
+
+      LabelLink.where(id: link_ids, label_id: old_label_id)
         .update_all(label_id: new_label_id)
     end