Use a better performing query to find all MRs for pipeline

And add some specs.

app/models/ci/pipeline.rb

@@ -80,22 +80,22 @@ module Ci
       end
 
       after_transition [:created, :pending] => :running do |pipeline|
-        pipeline.run_after_commit { PipelineMetricsWorker.perform_async(id) }
+        pipeline.run_after_commit { PipelineMetricsWorker.perform_async(pipeline.id) }
       end
 
       after_transition any => [:success] do |pipeline|
-        pipeline.run_after_commit { PipelineMetricsWorker.perform_async(id) }
+        pipeline.run_after_commit { PipelineMetricsWorker.perform_async(pipeline.id) }
       end
 
       after_transition [:created, :pending, :running] => :success do |pipeline|
-        pipeline.run_after_commit { PipelineSuccessWorker.perform_async(id) }
+        pipeline.run_after_commit { PipelineSuccessWorker.perform_async(pipeline.id) }
       end
 
       after_transition do |pipeline, transition|
         next if transition.loopback?
 
         pipeline.run_after_commit do
-          PipelineHooksWorker.perform_async(id)
+          PipelineHooksWorker.perform_async(pipeline.id)
           ExpirePipelineCacheWorker.perform_async(pipeline.id)
         end
       end
@@ -386,9 +386,7 @@ module Ci
 
     # All the merge requests for which the current pipeline runs/ran against
     def all_merge_requests
-      @all_merge_requests ||= project.merge_requests
-        .where(source_branch: ref)
-        .select { |merge_request| merge_request.all_pipelines.includes(self) }
+      @all_merge_requests ||= project.merge_requests.where(source_branch: ref)
     end
 
     def detailed_status(current_user)

app/workers/expire_pipeline_cache_worker.rb

@@ -2,8 +2,8 @@ class ExpirePipelineCacheWorker
   include Sidekiq::Worker
   include PipelineQueue
 
-  def perform(id)
-    pipeline = Ci::Pipeline.find(id)
+  def perform(pipeline_id)
+    pipeline = Ci::Pipeline.find(pipeline_id)
     project = pipeline.project
     store = Gitlab::EtagCaching::Store.new
 

changelogs/unreleased/tc-realtime-every-pipeline-on-mr.yml

+---
+title: Properly expire cache for all MRs of a pipeline
+merge_request: 10770
+author:

spec/models/ci/pipeline_spec.rb

@@ -1037,6 +1037,30 @@ describe Ci::Pipeline, models: true do
     end
   end
 
+  describe "#all_merge_requests" do
+    let(:project) { create(:project, :repository) }
+    let(:pipeline) { create(:ci_empty_pipeline, status: 'created', project: project, ref: 'master', sha: project.repository.commit('master').id) }
+
+    it "returns merge requests whose `diff_head_sha` matches the pipeline's SHA" do
+      merge_request = create(:merge_request, source_project: project, source_branch: pipeline.ref)
+
+      expect(pipeline.all_merge_requests).to eq([merge_request])
+    end
+
+    it "returns merge requests whose source branch matches the pipeline's source branch" do
+      pipeline = create(:ci_empty_pipeline, status: 'created', project: project, ref: 'master', sha: project.repository.commit('master^').id)
+      merge_request = create(:merge_request, source_project: project, source_branch: pipeline.ref)
+
+      expect(pipeline.all_merge_requests).to eq([merge_request])
+    end
+
+    it "doesn't return merge requests whose source branch doesn't match the pipeline's ref" do
+      create(:merge_request, source_project: project, source_branch: 'feature', target_branch: 'master')
+
+      expect(pipeline.all_merge_requests).to be_empty
+    end
+  end
+
   describe '#stuck?' do
     before do
       create(:ci_build, :pending, pipeline: pipeline)

spec/workers/expire_pipeline_cache_worker_spec.rb

@@ -7,7 +7,7 @@ describe ExpirePipelineCacheWorker do
   subject { described_class.new }
 
   describe '#perform' do
-    it 'invalidate Etag caching for project pipelines path' do
+    it 'invalidates Etag caching for project pipelines path' do
       pipelines_path = "/#{project.full_path}/pipelines.json"
       new_mr_pipelines_path = "/#{project.full_path}/merge_requests/new.json"
 
@@ -17,6 +17,18 @@ describe ExpirePipelineCacheWorker do
       subject.perform(pipeline.id)
     end
 
+    it 'invalidates Etag caching for merge request pipelines if pipeline runs on any commit of that source branch' do
+      project = create(:project, :repository)
+      pipeline = create(:ci_empty_pipeline, status: 'created', project: project, ref: 'master', sha: project.repository.commit('master^').id)
+      merge_request = create(:merge_request, source_project: project, source_branch: pipeline.ref)
+      merge_request_pipelines_path = "/#{project.full_path}/merge_requests/#{merge_request.iid}/pipelines.json"
+
+      allow_any_instance_of(Gitlab::EtagCaching::Store).to receive(:touch)
+      expect_any_instance_of(Gitlab::EtagCaching::Store).to receive(:touch).with(merge_request_pipelines_path)
+
+      subject.perform(pipeline.id)
+    end
+
     it 'updates the cached status for a project' do
       expect(Gitlab::Cache::Ci::ProjectPipelineStatus).to receive(:update_for_pipeline).
                                                             with(pipeline)