Fix wrong MR link in pipeline failure email

This MR fixes the pipeline failure email bug

app/mailers/emails/pipelines.rb

@@ -15,7 +15,13 @@ module Emails
     def pipeline_mail(pipeline, recipients, status)
       @project = pipeline.project
       @pipeline = pipeline
-      @merge_request = pipeline.all_merge_requests.first
+
+      @merge_request = if pipeline.merge_request?
+                         pipeline.merge_request
+                       else
+                         pipeline.merge_requests_as_head_pipeline.first
+                       end
+
       add_headers
 
       # We use bcc here because we don't want to generate these emails for a

changelogs/unreleased/fix-wrong-mr-id-in-pipeline-failure-email.yml

+---
+title: Fix wrong MR link is shown on pipeline failure email
+merge_request:
+author:
+type: fixed

spec/mailers/emails/pipelines_spec.rb

@@ -19,6 +19,25 @@ describe Emails::Pipelines do
       expect(subject).to have_body_text status_text
     end
 
+    context 'when pipeline on master branch has a merge request' do
+      let(:pipeline) { create(:ci_pipeline, ref: 'master', sha: sha, project: project) }
+
+      let!(:merge_request) do
+        create(:merge_request, source_branch: 'master', target_branch: 'feature',
+          source_project: project, target_project: project)
+      end
+
+      it 'has correct information that there is no merge request link' do
+        expect(subject)
+            .to have_subject "#{project.name} | Pipeline ##{pipeline.id} has " \
+                             "#{status} for #{pipeline.source_ref} | " \
+                             "#{pipeline.short_sha}".to_s
+
+        expect(subject).to have_body_text pipeline.source_ref
+        expect(subject).to have_body_text status_text
+      end
+    end
+
     context 'when pipeline for merge requests' do
       let(:pipeline) { merge_request.all_pipelines.first }
 
@@ -28,7 +47,7 @@ describe Emails::Pipelines do
           target_project: project)
       end
 
-      it 'has a correct information with merge request link' do
+      it 'has correct information that there is a merge request link' do
         expect(subject)
           .to have_subject "#{project.name} | Pipeline ##{pipeline.id} has " \
                            "#{status} for #{pipeline.source_ref} | " \
@@ -39,6 +58,27 @@ describe Emails::Pipelines do
         expect(subject).not_to have_body_text pipeline.ref
       end
     end
+
+    context 'when branch pipeline is set to a merge request as a head pipeline' do
+      let(:pipeline) do
+        create(:ci_pipeline, project: project, ref: ref, sha: sha,
+          merge_requests_as_head_pipeline: [merge_request])
+      end
+
+      let(:merge_request) do
+        create(:merge_request, source_project: project, target_project: project)
+      end
+
+      it 'has correct information that there is a merge request link' do
+        expect(subject)
+          .to have_subject "#{project.name} | Pipeline ##{pipeline.id} has " \
+                           "#{status} for #{pipeline.source_ref} | " \
+                           "#{pipeline.short_sha} in !#{merge_request.iid}".to_s
+
+        expect(subject).to have_body_text merge_request.to_reference
+        expect(subject).to have_body_text pipeline.source_ref
+      end
+    end
   end
 
   describe '#pipeline_success_email' do