Merge remote-tracking branch 'upstream/master' into 30634-protected-pipeline

* upstream/master: (67 commits)
  Revert "Merge branch 'revert-12499' into 'master'"
  Prevent accidental deletion of protected MR source branch by repeating checks before actual deletion
  Document that GitLab 9.3 requires the TRIGGER permission on MySQL
  Instrument Unicorn with Ruby exporter
  Remove group modal like remove project modal. Closes #33130
  Update prometheus client gem
  Enables the option in user preferences to turn on the new navigation
  Simplify authentication logic in the v4 users API for !12445.
  wait_for_requests is not needed when AJAX is not in play
  Don't resolve fork relationships for projects pending delete
  Clean up the ForkedProjectLink specs
  Remove unnecessary clear_stubs calls
  Add test for GitalyClient::Ref#find_ref_name
  DeleteMergedBranchesService should not delete protected branches
  Optimize creation of commit API by using Repository#commit instead of Repository#commits
  Update CHANGELOG.md for 9.3.4
  Make autosize fields more performant and remove broken autosize handle
  Update GITLAB_SHELL_VERSION to 5.1.1
  Fixed the y_label not setting correctly for each graph on the monitoring dashboard
  Refactor and copyedit "Using Docker images" docs
  ...

1 files changed, 8 insertions, 0 deletions

diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index d178ee4422b..41c8b525273 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -102,6 +102,14 @@ module Issuable
     def locking_enabled?
       title_changed? || description_changed?
     end
+
+    def allows_multiple_assignees?
+      false
+    end
+
+    def has_multiple_assignees?
+      assignees.count > 1
+    end
   end
 
   module ClassMethods