Merge branch '345349-catch-danger-insufficient-permission' into 'master'

Warn when Danger cannot apply labels

See merge request gitlab-org/gitlab!74274

Dangerfile

@@ -19,10 +19,17 @@ anything_to_post = status_report.values.any? { |data| data.any? }
 
 return unless helper.ci?
 
-if project_helper.labels_to_add.any?
+def post_labels
   gitlab.api.update_merge_request(gitlab.mr_json['project_id'],
                                   gitlab.mr_json['iid'],
                                   add_labels: project_helper.labels_to_add.join(','))
+rescue Gitlab::Error::Forbidden
+  labels = project_helper.labels_to_add.map { |label| %Q(~"#{label}") }
+  warn("This Merge Request needs to be labelled with #{labels.join(' ')}. Please request a reviewer or maintainer to add them.")
+end
+
+if project_helper.labels_to_add.any?
+  post_labels
 end
 
 if anything_to_post