Make sure that CI jobs are preloaded

Because artifact's job is now used also when rendering
pipeline jobs (if merge_request_cached_pipeline_serializer flag is
enabled), we should preload jobs independently on non_public_artifacts
flag enablement.

app/models/ci/job_artifact.rb

@@ -136,11 +136,7 @@ module Ci
     scope :for_sha, ->(sha, project_id) { joins(job: :pipeline).where(ci_pipelines: { sha: sha, project_id: project_id }) }
     scope :for_job_name, ->(name) { joins(:job).where(ci_builds: { name: name }) }
 
-    scope :with_job, -> do
-      if Feature.enabled?(:non_public_artifacts, type: :development)
-        joins(:job).includes(:job)
-      end
-    end
+    scope :with_job, -> { joins(:job).includes(:job) }
 
     scope :with_file_types, -> (file_types) do
       types = self.file_types.select { |file_type| file_types.include?(file_type) }.values

spec/requests/projects/merge_requests/content_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'merge request content spec' do
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:merge_request) { create(:merge_request, :with_head_pipeline, target_project: project, source_project: project) }
+  let_it_be(:ci_build) { create(:ci_build, :artifacts, pipeline: merge_request.head_pipeline) }
+
+  before do
+    sign_in(user)
+    project.add_maintainer(user)
+  end
+
+  shared_examples 'cached widget request' do
+    it 'avoids N+1 queries when multiple job artifacts are present' do
+      control = ActiveRecord::QueryRecorder.new(skip_cached: false) do
+        get cached_widget_project_json_merge_request_path(project, merge_request, format: :json)
+      end
+
+      create_list(:ci_build, 10, :artifacts, pipeline: merge_request.head_pipeline)
+
+      expect do
+        get cached_widget_project_json_merge_request_path(project, merge_request, format: :json)
+      end.not_to exceed_query_limit(control)
+    end
+  end
+
+  describe 'GET cached_widget' do
+    it_behaves_like 'cached widget request'
+
+    context 'with non_public_artifacts disabled' do
+      before do
+        stub_feature_flags(non_public_artifacts: false)
+      end
+
+      it_behaves_like 'cached widget request'
+    end
+  end
+end