Use MergeRequest#merge_base_pipeline for comparing Metrics reports [RUN ALL RSPEC] [RUN AS-IF-FOSS]

app/models/merge_request.rb

@@ -37,6 +37,7 @@ class MergeRequest < ApplicationRecord
   SORTING_PREFERENCE_FIELD = :merge_requests_sort
 
   ALLOWED_TO_USE_MERGE_BASE_PIPELINE_FOR_COMPARISON = {
+    'Ci::CompareMetricsReportsService'     => ->(project) { ::Gitlab::Ci::Features.merge_base_pipeline_for_metrics_comparison?(project) },
     'Ci::CompareCodequalityReportsService' => ->(project) { true }
   }.freeze
 

config/feature_flags/development/merge_base_pipeline_for_metrics_comparison.yml

+---
+name: merge_base_pipeline_for_metrics_comparison
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/61282
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/330809
+milestone: '13.12'
+type: development
+group: group::testing
+default_enabled: false

lib/gitlab/ci/features.rb

@@ -18,6 +18,10 @@ module Gitlab
         Feature.enabled?(:ci_pipeline_status_omit_commit_sha_in_cache_key, project, default_enabled: true)
       end
 
+      def self.merge_base_pipeline_for_metrics_comparison?(project)
+        Feature.enabled?(:merge_base_pipeline_for_metrics_comparison, project, default_enabled: :yaml)
+      end
+
       # Remove in https://gitlab.com/gitlab-org/gitlab/-/issues/224199
       def self.store_pipeline_messages?(project)
         ::Feature.enabled?(:ci_store_pipeline_messages, project, default_enabled: true)

spec/models/merge_request_spec.rb

@@ -3876,6 +3876,20 @@ RSpec.describe MergeRequest, factory_default: :keep do
 
     subject { merge_request.use_merge_base_pipeline_for_comparison?(service_class) }
 
+    context 'when service class is Ci::CompareMetricsReportsService' do
+      let(:service_class) { 'Ci::CompareMetricsReportsService' }
+
+      it { is_expected.to be_truthy }
+
+      context 'with the metrics report flag disabled' do
+        before do
+          stub_feature_flags(merge_base_pipeline_for_metrics_comparison: false)
+        end
+
+        it { is_expected.to be_falsey }
+      end
+    end
+
     context 'when service class is Ci::CompareCodequalityReportsService' do
       let(:service_class) { 'Ci::CompareCodequalityReportsService' }