Clone epic data when cloning issues

When using the clone quick action we should also clone epic data!

app/services/issues/clone_service.rb

@@ -88,3 +88,5 @@ module Issues
     end
   end
 end
+
+Issues::CloneService.prepend_if_ee('EE::Issues::CloneService')

ee/app/services/ee/issues/clone_service.rb

+# frozen_string_literal: true
+
+module EE
+  module Issues
+    module CloneService
+      extend ::Gitlab::Utils::Override
+
+      override :update_new_entity
+      def update_new_entity
+        super
+        add_epic
+      end
+
+      private
+
+      def add_epic
+        return unless epic = original_entity.epic
+        return unless can?(current_user, :update_epic, epic.group)
+
+        updated = ::Issues::UpdateService.new(target_project, current_user, epic: epic).execute(new_entity)
+
+        ::Gitlab::UsageDataCounters::IssueActivityUniqueCounter.track_issue_changed_epic_action(author: current_user) if updated
+      end
+    end
+  end
+end

ee/changelogs/unreleased/9421-epics-should-clone.yml

+---
+title: Clone epic data when cloning issues
+merge_request: 50097
+author:
+type: added

ee/spec/services/ee/issues/clone_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Issues::CloneService do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:group) { create(:group) }
+  let_it_be(:old_project) { create(:project, group: group) }
+  let_it_be(:new_project) { create(:project, group: group) }
+  let_it_be(:old_issue, reload: true) { create(:issue, project: old_project, author: user) }
+
+  let(:clone_service) { described_class.new(old_project, user) }
+
+  subject { clone_service.execute(old_issue, new_project) }
+
+  before do
+    group.add_reporter(user)
+  end
+
+  describe '#execute' do
+    context 'group issue hooks' do
+      let_it_be(:hook) { create(:group_hook, group: group, issues_events: true) }
+
+      it 'executes group issue hooks' do
+        allow_next_instance_of(WebHookService) do |instance|
+          allow(instance).to receive(:execute)
+        end
+
+        # Ideally, we'd test that `WebHookWorker.jobs.size` increased by 1,
+        # but since the entire spec run takes place in a transaction, we never
+        # actually get to the `after_commit` hook that queues these jobs.
+        expect { subject }
+        .not_to raise_error # Sidekiq::Worker::EnqueueFromTransactionError
+      end
+    end
+
+    context 'resource weight events' do
+      let_it_be(:old_issue) { create(:issue, project: old_project, author: user, weight: 5) }
+      let_it_be(:event1) { create(:resource_weight_event, issue: old_issue, weight: 1) }
+      let_it_be(:event2) { create(:resource_weight_event, issue: old_issue, weight: 42) }
+      let_it_be(:event3) { create(:resource_weight_event, issue: old_issue, weight: 5) }
+
+      let_it_be(:another_old_issue) { create(:issue, project: new_project, author: user) }
+      let_it_be(:event4) { create(:resource_weight_event, issue: another_old_issue, weight: 2) }
+
+      it 'creates expected resource weight events' do
+        expect(subject.resource_weight_events.map(&:weight)).to contain_exactly(1, 42, 5)
+      end
+    end
+
+    context 'epics' do
+      context 'issue assigned to epic' do
+        let_it_be(:epic) { create(:epic, group: group) }
+
+        before do
+          stub_licensed_features(epics: true)
+          create(:epic_issue, issue: old_issue, epic: epic)
+        end
+
+        it 'creates epic reference' do
+          expect(subject.epic).to eq(epic)
+        end
+
+        it 'tracks usage data for changed epic action' do
+          expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).to receive(:track_issue_changed_epic_action).with(author: user)
+
+          subject
+        end
+
+        context 'user can not update the epic' do
+          before do
+            group.group_member(user).destroy!
+            old_project.add_reporter(user)
+            new_project.add_reporter(user)
+          end
+
+          it 'ignores epic reference' do
+            expect(subject.epic).to be_nil
+          end
+
+          it 'does not send usage data for changed epic action' do
+            expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).not_to receive(:track_issue_changed_epic_action)
+
+            subject
+          end
+        end
+
+        context 'epic update fails' do
+          it 'does not send usage data for changed epic action' do
+            allow_next_instance_of(::Issues::UpdateService) do |update_service|
+              allow(update_service).to receive(:execute).and_return(false)
+            end
+
+            expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).not_to receive(:track_issue_changed_epic_action)
+
+            subject
+          end
+        end
+      end
+    end
+  end
+end

ee/spec/services/issues/clone_service_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Issues::CloneService do
-  let_it_be(:user) { create(:user) }
-  let_it_be(:author) { create(:user) }
-  let_it_be(:group) { create(:group, :private) }
-  let_it_be(:epic) { create(:epic, group: group) }
-  let_it_be(:sub_group_1) { create(:group, :private, parent: group) }
-  let_it_be(:old_project) { create(:project, namespace: group) }
-  let_it_be(:new_project) { create(:project, namespace: sub_group_1) }
-  let_it_be(:old_issue) { create(:issue, project: old_project, author: author, epic: epic) }
-
-  subject(:clone_service) do
-    described_class.new(old_project, user)
-  end
-
-  let(:new_issue) { clone_service.execute(old_issue, new_project) }
-
-  context 'user has enough permissions' do
-    before do
-      old_project.add_reporter(user)
-      new_project.add_reporter(user)
-    end
-
-    it 'does not copy epic' do
-      expect(new_issue.epic).to be_nil
-    end
-  end
-end