Create ProjectSetting during project creation

This is missed because ProjectSetting object is always created, but
without saving it to the database.

app/services/projects/create_service.rb

@@ -105,7 +105,8 @@ module Projects
       end
 
       @project.track_project_repository
-      @project.create_project_setting unless @project.project_setting
+
+      create_project_settings
 
       yield if block_given?
 
@@ -122,6 +123,14 @@ module Projects
       create_sast_commit if @initialize_with_sast
     end
 
+    def create_project_settings
+      if Feature.enabled?(:create_project_settings, default_enabled: :yaml)
+        @project.project_setting.save if @project.project_setting.changed?
+      else
+        @project.create_project_setting unless @project.project_setting
+      end
+    end
+
     # Add an authorization for the current user authorizations inline
     # (so they can access the project immediately after this request
     # completes), and any other affected users in the background

config/feature_flags/development/create_project_settings.yml

+---
+name: create_project_settings
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/84502
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/358136
+milestone: '14.10'
+type: development
+group: group::authentication and authorization
+default_enabled: false

spec/requests/api/project_import_spec.rb

@@ -47,7 +47,7 @@ RSpec.describe API::ProjectImport, :aggregate_failures do
     it 'executes a limited number of queries' do
       control_count = ActiveRecord::QueryRecorder.new { subject }.count
 
-      expect(control_count).to be <= 105
+      expect(control_count).to be <= 108
     end
 
     it 'schedules an import using a namespace' do

spec/services/projects/create_service_spec.rb

@@ -135,10 +135,22 @@ RSpec.describe Projects::CreateService, '#execute' do
       create_project(user, opts)
     end
 
-    it 'builds associated project settings' do
+    it 'creates associated project settings' do
       project = create_project(user, opts)
 
-      expect(project.project_setting).to be_new_record
+      expect(project.project_setting).to be_persisted
+    end
+
+    context 'create_project_settings feature flag is disabled' do
+      before do
+        stub_feature_flags(create_project_settings: false)
+      end
+
+      it 'builds associated project settings' do
+        project = create_project(user, opts)
+
+        expect(project.project_setting).to be_new_record
+      end
     end
 
     it_behaves_like 'storing arguments in the application context' do