Fix merge requst relationships with pipeline in MWPSService

MWPSService currently uses the old pipeline lookup method. It searches
related merge requests with pipeline.ref, however, this doesn't work
for attached/detached merge request pipelines.

app/services/merge_requests/add_todo_when_build_fails_service.rb

@@ -7,7 +7,7 @@ module MergeRequests
     def execute(commit_status)
       return if commit_status.allow_failure? || commit_status.retried?
 
-      commit_status_merge_requests(commit_status) do |merge_request|
+      pipeline_merge_requests(commit_status.pipeline) do |merge_request|
         todo_service.merge_request_build_failed(merge_request)
       end
     end
@@ -16,7 +16,7 @@ module MergeRequests
     # build is retried
     #
     def close(commit_status)
-      commit_status_merge_requests(commit_status) do |merge_request|
+      pipeline_merge_requests(commit_status.pipeline) do |merge_request|
         todo_service.merge_request_build_retried(merge_request)
       end
     end

app/services/merge_requests/base_service.rb

@@ -99,22 +99,11 @@ module MergeRequests
     # rubocop: enable CodeReuse/ActiveRecord
 
     def pipeline_merge_requests(pipeline)
-      merge_requests_for(pipeline.ref).each do |merge_request|
+      pipeline.all_merge_requests.opened.each do |merge_request|
         next unless pipeline == merge_request.head_pipeline
 
         yield merge_request
       end
     end
-
-    def commit_status_merge_requests(commit_status)
-      merge_requests_for(commit_status.ref).each do |merge_request|
-        pipeline = merge_request.head_pipeline
-
-        next unless pipeline
-        next unless pipeline.sha == commit_status.sha
-
-        yield merge_request
-      end
-    end
   end
 end

changelogs/unreleased/fix-merge-request-relations-with-pipeline-on-mwps.yml

+---
+title: Fix MWPS does not work for merge request pipelines
+merge_request: 26906
+author:
+type: fixed

spec/models/ci/build_spec.rb

@@ -3216,7 +3216,7 @@ describe Ci::Build do
       it 'does not try to create a todo' do
         project.add_developer(user)
 
-        expect(service).not_to receive(:commit_status_merge_requests)
+        expect(service).not_to receive(:pipeline_merge_requests)
 
         subject.drop!
       end
@@ -3252,7 +3252,23 @@ describe Ci::Build do
     end
 
     context 'when build is not configured to be retried' do
-      subject { create(:ci_build, :running, project: project, user: user) }
+      subject { create(:ci_build, :running, project: project, user: user, pipeline: pipeline) }
+
+      let(:pipeline) do
+        create(:ci_pipeline,
+          project: project,
+          ref: 'feature',
+          sha: merge_request.diff_head_sha,
+          merge_requests_as_head_pipeline: [merge_request])
+      end
+
+      let(:merge_request) do
+        create(:merge_request, :opened,
+          source_branch: 'feature',
+          source_project: project,
+          target_branch: 'master',
+          target_project: project)
+      end
 
       it 'does not retry build' do
         expect(described_class).not_to receive(:retry)
@@ -3271,7 +3287,10 @@ describe Ci::Build do
       it 'creates a todo' do
         project.add_developer(user)
 
-        expect(service).to receive(:commit_status_merge_requests)
+        expect_next_instance_of(TodoService) do |todo_service|
+          expect(todo_service)
+            .to receive(:merge_request_build_failed).with(merge_request)
+        end
 
         subject.drop!
       end

spec/services/merge_requests/add_todo_when_build_fails_service_spec.rb

@@ -77,6 +77,22 @@ describe MergeRequests::AddTodoWhenBuildFailsService do
         service.execute(commit_status)
       end
     end
+
+    context 'when build belongs to a merge request pipeline' do
+      let(:pipeline) do
+        create(:ci_pipeline, source: :merge_request_event,
+                             ref: merge_request.merge_ref_path,
+                             merge_request: merge_request,
+                             merge_requests_as_head_pipeline: [merge_request])
+      end
+
+      let(:commit_status) { create(:ci_build, ref: merge_request.merge_ref_path, pipeline: pipeline) }
+
+      it 'notifies the todo service' do
+        expect(todo_service).to receive(:merge_request_build_failed).with(merge_request)
+        service.execute(commit_status)
+      end
+    end
   end
 
   describe '#close' do
@@ -106,6 +122,22 @@ describe MergeRequests::AddTodoWhenBuildFailsService do
         service.close(commit_status)
       end
     end
+
+    context 'when build belongs to a merge request pipeline' do
+      let(:pipeline) do
+        create(:ci_pipeline, source: :merge_request_event,
+                             ref: merge_request.merge_ref_path,
+                             merge_request: merge_request,
+                             merge_requests_as_head_pipeline: [merge_request])
+      end
+
+      let(:commit_status) { create(:ci_build, ref: merge_request.merge_ref_path, pipeline: pipeline) }
+
+      it 'notifies the todo service' do
+        expect(todo_service).to receive(:merge_request_build_retried).with(merge_request)
+        service.close(commit_status)
+      end
+    end
   end
 
   describe '#close_all' do

spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb

@@ -112,6 +112,21 @@ describe MergeRequests::MergeWhenPipelineSucceedsService do
         service.trigger(unrelated_pipeline)
       end
     end
+
+    context 'when pipeline is merge request pipeline' do
+      let(:pipeline) do
+        create(:ci_pipeline, :success,
+          source: :merge_request_event,
+          ref: mr_merge_if_green_enabled.merge_ref_path,
+          merge_request: mr_merge_if_green_enabled,
+          merge_requests_as_head_pipeline: [mr_merge_if_green_enabled])
+      end
+
+      it 'merges the associated merge request' do
+        expect(MergeWorker).to receive(:perform_async)
+        service.trigger(pipeline)
+      end
+    end
   end
 
   describe "#cancel" do