Rescue RecordNotUnique when pipeline is created with non-unique iid

lib/gitlab/ci/pipeline/chain/create.rb

@@ -23,7 +23,7 @@ module Gitlab
                 end
               end
             end
-          rescue ActiveRecord::RecordInvalid => e
+          rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotUnique => e
             error("Failed to persist the pipeline: #{e}")
           end
 

spec/lib/gitlab/ci/pipeline/chain/create_spec.rb

@@ -37,6 +37,18 @@ describe Gitlab::Ci::Pipeline::Chain::Create do
   end
 
   context 'when pipeline has validation errors' do
+    shared_examples_for 'expectations' do
+      it 'breaks the chain' do
+        expect(step.break?).to be true
+      end
+  
+      it 'appends validation error' do
+        expect(pipeline.errors.to_a)
+          .to include /Failed to persist the pipeline/
+      end
+    end
+    
+    context 'when ref is nil' do
       let(:pipeline) do
         build(:ci_pipeline, project: project, ref: nil)
       end
@@ -45,13 +57,18 @@ describe Gitlab::Ci::Pipeline::Chain::Create do
         step.perform!
       end
 
-    it 'breaks the chain' do
-      expect(step.break?).to be true
+      it_behaves_like 'expectations'
     end
 
-    it 'appends validation error' do
-      expect(pipeline.errors.to_a)
-        .to include /Failed to persist the pipeline/
+    context 'when pipeline has a duplicate iid' do
+      before do
+        allow_any_instance_of(Ci::Pipeline).to receive(:ensure_project_iid!) { |p| p.send(:write_attribute, :iid, 1) }
+        create(:ci_pipeline, project: project)
+  
+        step.perform!
+      end
+
+      it_behaves_like 'expectations'
     end
   end
 end

spec/models/ci/pipeline_spec.rb

@@ -41,7 +41,7 @@ describe Ci::Pipeline, :mailer do
       let(:instance) { build(:ci_pipeline) }
       let(:scope_attrs) { { project: instance.project } }
       let(:usage) { :ci_pipelines }
-      let(:validate_presence) { false }
+      let(:allow_nil) { true }
     end
   end
 

spec/support/shared_examples/models/atomic_internal_id_spec.rb

 require 'spec_helper'
 
 shared_examples_for 'AtomicInternalId' do
-  let(:validate_presence) { true }
+  let(:allow_nil) { false }
 
   describe '.has_internal_id' do
     describe 'Module inclusion' do
@@ -18,7 +18,11 @@ shared_examples_for 'AtomicInternalId' do
       it 'validates presence' do
         instance.valid?
 
-        expect(instance.errors[:iid]).to include("can't be blank") if validate_presence
+        if allow_nil
+          expect(instance.errors[:iid]).to be_empty
+        else
+          expect(instance.errors[:iid]).to include("can't be blank")
+        end
       end
     end