Fix incorrect rendering of flash messages

Flash messages are not cleared unless they are accessed in
a request. Our JSON requests don't read the flash causing these
messages to persist to unrelated requests.

We fix this by only setting the flash message for non-AJAX
HTML requests.

app/controllers/concerns/routable_actions.rb

@@ -47,7 +47,7 @@ module RoutableActions
 
     canonical_path = routable.full_path
     if canonical_path != requested_full_path
-      if canonical_path.casecmp(requested_full_path) != 0
+      if !request.xhr? && request.format.html? && canonical_path.casecmp(requested_full_path) != 0
         flash[:notice] = "#{routable.class.to_s.titleize} '#{requested_full_path}' was moved to '#{canonical_path}'. Please update any links and bookmarks that may still have the old path."
       end
 

changelogs/unreleased/32198-banner-alerting-of-project-move-is-showing-up-everywhere.yml

+---
+title: Fix "project or group was moved" alerts showing up in the wrong pages
+merge_request: 18985
+author:
+type: fixed

spec/controllers/groups/milestones_controller_spec.rb

@@ -314,6 +314,24 @@ describe Groups::MilestonesController do
           expect(controller).to set_flash[:notice].to(group_moved_message(redirect_route, group))
         end
 
+        context 'with an AJAX request' do
+          it 'redirects to the canonical path but does not set flash message' do
+            get :merge_requests, params: { group_id: redirect_route.path, id: title }, xhr: true
+
+            expect(response).to redirect_to(merge_requests_group_milestone_path(group.to_param, title))
+            expect(controller).not_to set_flash[:notice]
+          end
+        end
+
+        context 'with JSON format' do
+          it 'redirects to the canonical path but does not set flash message' do
+            get :merge_requests, params: { group_id: redirect_route.path, id: title }, format: :json
+
+            expect(response).to redirect_to(merge_requests_group_milestone_path(group.to_param, title, format: :json))
+            expect(controller).not_to set_flash[:notice]
+          end
+        end
+
         context 'when the old group path is a substring of the scheme or host' do
           let(:redirect_route) { group.redirect_routes.create(path: 'http') }
 

spec/controllers/projects/labels_controller_spec.rb

@@ -204,6 +204,24 @@ describe Projects::LabelsController do
           expect(response).to redirect_to(project_labels_path(project))
           expect(controller).to set_flash[:notice].to(project_moved_message(redirect_route, project))
         end
+
+        context 'with an AJAX request' do
+          it 'redirects to the canonical path but does not set flash message' do
+            get :index, params: { namespace_id: project.namespace, project_id: project.to_param + 'old' }, xhr: true
+
+            expect(response).to redirect_to(project_labels_path(project))
+            expect(controller).not_to set_flash[:notice]
+          end
+        end
+
+        context 'with JSON format' do
+          it 'redirects to the canonical path but does not set flash message' do
+            get :index, params: { namespace_id: project.namespace, project_id: project.to_param + 'old' }, format: :json
+
+            expect(response).to redirect_to(project_labels_path(project, format: :json))
+            expect(controller).not_to set_flash[:notice]
+          end
+        end
       end
     end
   end