Add service to perform some of the issue after creation tasks

app/services/issues/after_create_service.rb

+# frozen_string_literal: true
+
+module Issues
+  class AfterCreateService < Issues::BaseService
+    def execute(issue)
+      todo_service.new_issue(issue, current_user)
+      delete_milestone_total_issue_counter_cache(issue.milestone)
+      track_incident_action(current_user, issue, :incident_created)
+    end
+  end
+end
+
+Issues::AfterCreateService.prepend_ee_mod

ee/app/services/ee/issues/after_create_service.rb

+# frozen_string_literal: true
+
+module EE
+  module Issues
+    module AfterCreateService
+      extend ::Gitlab::Utils::Override
+
+      override :execute
+      def execute(issue)
+        super
+
+        add_issue_sla(issue)
+      end
+
+      private
+
+      def add_issue_sla(issue)
+        return unless issue.sla_available?
+
+        ::IncidentManagement::Incidents::CreateSlaService.new(issue, current_user).execute
+      end
+    end
+  end
+end

ee/spec/services/ee/issues/after_create_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Issues::AfterCreateService do
+  include AfterNextHelpers
+
+  let_it_be(:project) { create(:project) }
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:issue) { create(:issue, project: project, author: current_user) }
+
+  subject(:after_create_service) { described_class.new(project, current_user) }
+
+  describe '#execute' do
+    context 'when issue sla is available' do
+      it 'calls IncidentManagement::Incidents::CreateSlaService' do
+        allow(issue).to receive(:sla_available?).and_return(true)
+
+        expect_next(::IncidentManagement::Incidents::CreateSlaService, issue, current_user)
+            .to receive(:execute)
+
+        after_create_service.execute(issue)
+      end
+    end
+
+    context 'when issue sla is not available' do
+      it 'does not call IncidentManagement::Incidents::CreateSlaService' do
+        allow(issue).to receive(:sla_available?).and_return(false)
+
+        expect(::IncidentManagement::Incidents::CreateSlaService)
+            .not_to receive(:new)
+
+        after_create_service.execute(issue)
+      end
+    end
+  end
+end

spec/services/issues/after_create_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Issues::AfterCreateService do
+  include AfterNextHelpers
+
+  let_it_be(:project) { create(:project) }
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:assignee) { create(:user) }
+  let_it_be(:milestone) { create(:milestone, project: project) }
+  let_it_be(:issue) { create(:issue, project: project, author: current_user, milestone: milestone, assignee_ids: [assignee.id]) }
+
+  subject(:after_create_service) { described_class.new(project, current_user) }
+
+  describe '#execute' do
+    it 'creates a pending todo for new assignee' do
+      attributes = {
+        project: project,
+        author: current_user,
+        user: assignee,
+        target_id: issue.id,
+        target_type: issue.class.name,
+        action: Todo::ASSIGNED,
+        state: :pending
+      }
+
+      expect { after_create_service.execute(issue) }.to change { Todo.where(attributes).count }.by(1)
+    end
+
+    it 'deletes milestone issues count cache' do
+      expect_next(Milestones::IssuesCountService, milestone)
+        .to receive(:delete_cache).and_call_original
+
+      after_create_service.execute(issue)
+    end
+
+    context 'with a regular issue' do
+      it_behaves_like 'does not track incident management event', :incident_management_incident_created do
+        subject { after_create_service.execute(issue) }
+      end
+    end
+
+    context 'with an incident issue' do
+      let(:issue) { create(:issue, :incident, project: project, author: current_user) }
+
+      it_behaves_like 'an incident management tracked event', :incident_management_incident_created do
+        subject { after_create_service.execute(issue) }
+      end
+    end
+  end
+end