Exclude coverage data from the pipelines page

app/controllers/projects/pipelines_controller.rb

@@ -34,7 +34,7 @@ class Projects::PipelinesController < Projects::ApplicationController
           pipelines: PipelineSerializer
             .new(project: @project, current_user: @current_user)
             .with_pagination(request, response)
-            .represent(@pipelines),
+            .represent(@pipelines, disable_coverage: true),
           count: {
             all: @pipelines_count,
             running: @running_count,

app/serializers/pipeline_entity.rb

@@ -4,7 +4,11 @@ class PipelineEntity < Grape::Entity
   expose :id
   expose :user, using: UserEntity
   expose :active?, as: :active
-  expose :coverage
+
+  # Coverage isn't always necessary (e.g. when displaying project pipelines in
+  # the UI). Instead of creating an entirely different entity we just allow the
+  # disabling of this specific field whenever necessary.
+  expose :coverage, unless: proc { options[:disable_coverage] }
   expose :source
 
   expose :created_at, :updated_at

spec/controllers/projects/pipelines_controller_spec.rb

@@ -41,6 +41,12 @@ describe Projects::PipelinesController do
       expect(json_response['count']['finished']).to eq '1'
     end
 
+    it 'does not include coverage data for the pipelines' do
+      subject
+
+      expect(json_response['pipelines'][0]).not_to include('coverage')
+    end
+
     context 'when performing gitaly calls', :request_store do
       it 'limits the Gitaly requests' do
         expect { subject }.to change { Gitlab::GitalyClient.get_request_count }.by(3)

spec/serializers/pipeline_entity_spec.rb

@@ -26,6 +26,13 @@ describe PipelineEntity do
         expect(subject).to include :updated_at, :created_at
       end
 
+      it 'excludes coverage data when disabled' do
+        entity = described_class
+          .represent(pipeline, request: request, disable_coverage: true)
+
+        expect(entity.as_json).not_to include(:coverage)
+      end
+
       it 'contains details' do
         expect(subject).to include :details
         expect(subject[:details])