Drop merge_check endpoint and use only MR show instead

app/assets/javascripts/vue_merge_request_widget/services/mr_widget_service.js

@@ -6,7 +6,7 @@ Vue.use(VueResource);
 export default class MRWidgetService {
   constructor(endpoints) {
     this.mergeResource = Vue.resource(endpoints.mergePath);
-    this.mergeCheckResource = Vue.resource(endpoints.mergeCheckPath);
+    this.mergeCheckResource = Vue.resource(endpoints.statusPath);
     this.cancelAutoMergeResource = Vue.resource(endpoints.cancelAutoMergePath);
     this.removeWIPResource = Vue.resource(endpoints.removeWIPPath);
     this.removeSourceBranchResource = Vue.resource(endpoints.sourceBranchPath);

app/controllers/projects/merge_requests_controller.rb

@@ -9,14 +9,15 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   before_action :module_enabled
   before_action :merge_request, only: [
-    :edit, :update, :show, :diffs, :commits, :conflicts, :conflict_for_path, :pipelines, :merge, :merge_check,
+    :edit, :update, :show, :diffs, :commits, :conflicts, :conflict_for_path, :pipelines, :merge,
     :pipeline_status, :ci_environments_status, :toggle_subscription, :cancel_merge_when_pipeline_succeeds, :remove_wip, :resolve_conflicts, :assign_related_issues, :commit_change_content
   ]
   before_action :validates_merge_request, only: [:show, :diffs, :commits, :pipelines]
-  before_action :define_show_vars, only: [:show, :diffs, :commits, :conflicts, :conflict_for_path, :builds, :pipelines]
+  before_action :define_show_vars, only: [:diffs, :commits, :conflicts, :conflict_for_path, :builds, :pipelines]
   before_action :define_commit_vars, only: [:diffs]
   before_action :ensure_ref_fetched, only: [:show, :diffs, :commits, :builds, :conflicts, :conflict_for_path, :pipelines]
   before_action :close_merge_request_without_source_project, only: [:show, :diffs, :commits, :builds, :pipelines]
+  before_action :check_if_can_be_merged, only: :show
   before_action :apply_diff_view_cookie!, only: [:new_diffs]
   before_action :build_merge_request, only: [:new, :new_diffs]
 
@@ -75,9 +76,12 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     respond_to do |format|
       format.html do
         define_discussion_vars
+        define_show_vars
       end
 
       format.json do
+        Gitlab::PollingInterval.set_header(response, interval: 10_000)
+
         render json: serializer.represent(@merge_request, basic: params[:basic])
       end
 
@@ -309,12 +313,6 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     render json: serializer.represent(@merge_request)
   end
 
-  def merge_check
-    @merge_request.check_if_can_be_merged
-
-    render json: serializer.represent(@merge_request)
-  end
-
   def commit_change_content
     render partial: 'projects/merge_requests/widget/commit_change_content', layout: false
   end
@@ -640,6 +638,10 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   private
 
+  def check_if_can_be_merged
+    @merge_request.check_if_can_be_merged
+  end
+
   def merge!
     # Disable the CI check if merge_when_pipeline_succeeds is enabled since we have
     # to wait until CI completes to know

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -119,6 +119,15 @@ describe Projects::MergeRequestsController do
           expect(response).to match_response_schema('entities/merge_request')
         end
       end
+
+      context 'number of queries' do
+        it 'verifies number of queries' do
+          recorded = ActiveRecord::QueryRecorder.new { go(format: :json) }
+
+          expect(recorded.count).to be_within(1).of(94)
+          expect(recorded.cached_count).to eq(0)
+        end
+      end
     end
 
     describe "as diff" do