Do not process jobs when pipeline activity limit exceeded

app/models/ci/pipeline.rb

@@ -5,6 +5,7 @@ module Ci
     include Importable
     include AfterCommitQueue
     include Presentable
+    include Gitlab::OptimisticLocking
 
     prepend ::EE::Ci::Pipeline
 
@@ -287,7 +288,7 @@ module Ci
     end
 
     def cancel_running
-      Gitlab::OptimisticLocking.retry_lock(cancelable_statuses) do |cancelable|
+      retry_optimistic_lock(cancelable_statuses) do |cancelable|
         cancelable.find_each do |job|
           yield(job) if block_given?
           job.cancel
@@ -431,7 +432,7 @@ module Ci
     end
 
     def update_status
-      Gitlab::OptimisticLocking.retry_lock(self) do
+      retry_optimistic_lock(self) do
         case latest_builds_status
         when 'pending' then enqueue
         when 'running' then run

ee/lib/ee/gitlab/ci/pipeline/chain/limit/activity.rb

@@ -18,18 +18,9 @@ module EE
               def perform!
                 return unless @limit.exceeded?
 
-                @pipeline.cancel_running
-
                 retry_optimistic_lock(@pipeline) do
                   @pipeline.drop!(:activity_limit_exceeded)
                 end
-
-                # TODO, should we invalidate the pipeline
-                # while it is already persisted?
-                #
-                # Should we show info in the UI or alert/warning?
-                #
-                error(@limit.message)
               end
 
               def break?

spec/ee/spec/lib/ee/gitlab/ci/pipeline/chain/limit/activity_spec.rb

@@ -6,18 +6,13 @@ describe EE::Gitlab::Ci::Pipeline::Chain::Limit::Activity do
   set(:user) { create(:user) }
 
   let(:command) do
-    double('command', project: project,
-                      current_user: user)
+    double('command', project: project, current_user: user)
   end
 
   let(:pipeline) do
     create(:ci_pipeline, project: project)
   end
 
-  before do
-    create(:ci_build, pipeline: pipeline)
-  end
-
   let(:step) { described_class.new(pipeline, command) }
 
   context 'when active pipelines limit is exceeded' do
@@ -38,11 +33,6 @@ describe EE::Gitlab::Ci::Pipeline::Chain::Limit::Activity do
       expect(pipeline).to be_persisted
     end
 
-    it 'cancels all pipeline jobs' do
-      expect(pipeline.statuses).not_to be_empty
-      expect(pipeline.statuses).to all(be_canceled)
-    end
-
     it 'breaks the chain' do
       expect(step.break?).to be true
     end

spec/ee/spec/services/ci/create_pipeline_service_spec.rb

@@ -37,13 +37,13 @@ describe Ci::CreatePipelineService, '#execute' do
         create(:ci_pipeline, project: project, status: 'running')
       end
 
-      it 'drops the pipeline and cancels all jobs' do
+      it 'drops the pipeline and does not process jobs' do
         pipeline = create_pipeline!
 
         expect(pipeline).to be_persisted
         expect(pipeline).to be_failed
         expect(pipeline.statuses).not_to be_empty
-        expect(pipeline.statuses).to all(be_canceled)
+        expect(pipeline.statuses).to all(be_created)
         expect(pipeline.activity_limit_exceeded?).to be true
       end
     end