Merge branch 'sh-fix-failure-project-destroy' into 'master'

Fix "Can't modify frozen hash" error when project is destroyed

See merge request gitlab-org/gitlab-ce!17816

app/services/projects/destroy_service.rb

@@ -88,7 +88,11 @@ module Projects
     def attempt_rollback(project, message)
       return unless project
-      project.update_attributes(delete_error: message, pending_delete: false)
+      # It's possible that the project was destroyed, but some after_commit
+      # hook failed and caused us to end up here. A destroyed model will be a frozen hash,
+      # which cannot be altered.
+      project.update_attributes(delete_error: message, pending_delete: false) unless project.destroyed?
+
       log_error("Deletion failed on #{project.full_path} with the following message: #{message}")
     end

changelogs/unreleased/sh-fix-failure-project-destroy.yml

+---
+title: Fix "Can't modify frozen hash" error when project is destroyed
+merge_request:
+author:
+type: fixed