Calculate mergeability check sync on first widget load

When an MR is loaded, we perform an async widget.json call
Currently, this first call performs mergeability check async
Let's perform it sync in order to deliver the current state
of the merge request faster

Changelog: fixed

app/controllers/projects/merge_requests/content_controller.rb

@@ -14,8 +14,6 @@ class Projects::MergeRequests::ContentController < Projects::MergeRequests::Appl
   SLOW_POLLING_INTERVAL = 5.minutes.in_milliseconds
 
   def widget
-    check_mergeability_async!
-
     respond_to do |format|
       format.json do
         render json: serializer(MergeRequestPollWidgetEntity)
@@ -40,13 +38,6 @@ class Projects::MergeRequests::ContentController < Projects::MergeRequests::Appl
 
   def serializer(entity)
     serializer = MergeRequestSerializer.new(current_user: current_user, project: merge_request.project)
-    serializer.represent(merge_request, { async_mergeability_check: params[:async_mergeability_check] }, entity)
-  end
-
-  def check_mergeability_async!
-    return unless Feature.enabled?(:check_mergeability_async_in_widget, merge_request.project, default_enabled: :yaml)
-    return if params[:async_mergeability_check].blank?
-
-    merge_request.check_mergeability(async: true)
+    serializer.represent(merge_request, {}, entity)
   end
 end

app/serializers/merge_request_poll_widget_entity.rb

@@ -31,7 +31,6 @@ class MergeRequestPollWidgetEntity < Grape::Entity
 
   expose :mergeable do |merge_request, options|
     next merge_request.mergeable? if Feature.disabled?(:check_mergeability_async_in_widget, merge_request.project, default_enabled: :yaml)
-    next false if options[:async_mergeability_check].present? && merge_request.checking?
 
     merge_request.mergeable?
   end

app/serializers/merge_request_widget_entity.rb

@@ -36,7 +36,7 @@ class MergeRequestWidgetEntity < Grape::Entity
   end
 
   expose :merge_request_widget_path do |merge_request|
-    widget_project_json_merge_request_path(merge_request.target_project, merge_request, async_mergeability_check: true, format: :json)
+    widget_project_json_merge_request_path(merge_request.target_project, merge_request, format: :json)
   end
 
   expose :merge_request_cached_widget_path do |merge_request|

app/views/projects/merge_requests/show.html.haml

@@ -62,7 +62,7 @@
                   - add_page_startup_api_call notes_url
                 - else
                   - add_page_startup_api_call discussions_path(@merge_request)
-                - add_page_startup_api_call widget_project_json_merge_request_path(@project, @merge_request, async_mergeability_check: true, format: :json)
+                - add_page_startup_api_call widget_project_json_merge_request_path(@project, @merge_request, format: :json)
                 - add_page_startup_api_call cached_widget_project_json_merge_request_path(@project, @merge_request, format: :json)
               #js-vue-mr-discussions{ data: { notes_data: notes_data(@merge_request, Feature.enabled?(:paginated_notes, @project)).to_json,
                 endpoint_metadata: @endpoint_metadata_url,

spec/controllers/projects/merge_requests/content_controller_spec.rb

@@ -57,17 +57,6 @@ RSpec.describe Projects::MergeRequests::ContentController do
         expect(response.headers['Poll-Interval']).to eq('10000')
       end
 
-      context 'when async_mergeability_check param is passed' do
-        it 'checks mergeability asynchronously' do
-          expect_next_instance_of(MergeRequests::MergeabilityCheckService) do |service|
-            expect(service).not_to receive(:execute)
-            expect(service).to receive(:async_execute).and_call_original
-          end
-
-          do_request(:widget, { async_mergeability_check: true })
-        end
-      end
-
       context 'merged merge request' do
         let(:merge_request) do
           create(:merged_merge_request, :with_test_reports, target_project: project, source_project: project)

spec/serializers/merge_request_poll_widget_entity_spec.rb

@@ -229,21 +229,13 @@ RSpec.describe MergeRequestPollWidgetEntity do
         expect(subject[:mergeable]).to eq(true)
       end
 
-      context 'when async_mergeability_check is passed' do
-        let(:options) { { async_mergeability_check: true } }
-
-        it 'returns false' do
-          expect(subject[:mergeable]).to eq(false)
+      context 'when check_mergeability_async_in_widget is disabled' do
+        before do
+          stub_feature_flags(check_mergeability_async_in_widget: false)
         end
 
-        context 'when check_mergeability_async_in_widget is disabled' do
-          before do
-            stub_feature_flags(check_mergeability_async_in_widget: false)
-          end
-
-          it 'calculates mergeability and returns true' do
-            expect(subject[:mergeable]).to eq(true)
-          end
+        it 'calculates mergeability and returns true' do
+          expect(subject[:mergeable]).to eq(true)
         end
       end
     end