Fix issue where project maintainers can not assign compliance frameworks

https://gitlab.com/gitlab-org/gitlab/-/merge_requests/53370 introduced
a regression which stopped project maintainers from assigning compliance
frameworks to a project.

This is an upcoming feature change which was designed to be
behind a feature flag.

This commit puts that change back behind the feature flag.

ee/app/policies/ee/project_policy.rb

@@ -60,6 +60,10 @@ module EE
         @subject.feature_available?(:project_merge_request_analytics)
       end
 
+      condition(:custom_compliance_framework_available) do
+        ::Feature.enabled?(:ff_custom_compliance_frameworks)
+      end
+
       with_scope :subject
       condition(:group_push_rules_enabled) do
         @subject.group && @subject.group.feature_available?(:push_rules)
@@ -402,6 +406,7 @@ module EE
       rule { requirements_available & owner }.enable :destroy_requirement
 
       rule { compliance_framework_available & can?(:owner_access) }.enable :admin_compliance_framework
+      rule { compliance_framework_available & can?(:maintainer_access) & ~custom_compliance_framework_available }.enable :admin_compliance_framework
 
       rule { status_page_available & can?(:owner_access) }.enable :mark_issue_for_publication
       rule { status_page_available & can?(:developer_access) }.enable :publish_status_page

ee/changelogs/unreleased/321380-compliance-framework-assignment-regression.yml

+---
+title: Fix issue where maintainers could not set compliance framework for projects
+merge_request: 54071
+author:
+type: fixed

ee/spec/policies/project_policy_spec.rb

@@ -1537,27 +1537,29 @@ RSpec.describe ProjectPolicy do
 
     let(:policy) { :admin_compliance_framework }
 
-    where(:role, :feature_enabled, :admin_mode, :allowed) do
-      :guest      | false | nil   | false
-      :guest      | true  | nil   | false
-      :reporter   | false | nil   | false
-      :reporter   | true  | nil   | false
-      :developer  | false | nil   | false
-      :developer  | true  | nil   | false
-      :maintainer | false | nil   | false
-      :maintainer | true  | nil   | false
-      :owner      | false | nil   | false
-      :owner      | true  | nil   | true
-      :admin      | false | false | false
-      :admin      | false | true  | false
-      :admin      | true  | false | false
-      :admin      | true  | true  | true
+    where(:role, :feature_enabled, :admin_mode, :custom_framework_flag, :allowed) do
+      :guest      | false | nil   | false | false
+      :guest      | true  | nil   | false | false
+      :reporter   | false | nil   | false | false
+      :reporter   | true  | nil   | false | false
+      :developer  | false | nil   | false | false
+      :developer  | true  | nil   | false | false
+      :maintainer | false | nil   | false | false
+      :maintainer | true  | nil   | false | true
+      :maintainer | true  | nil   | true  | false
+      :owner      | false | nil   | false | false
+      :owner      | true  | nil   | false | true
+      :admin      | false | false | false | false
+      :admin      | false | true  | false | false
+      :admin      | true  | false | false | false
+      :admin      | true  | true  | false | true
     end
 
     with_them do
       let(:current_user) { public_send(role) }
 
       before do
+        stub_feature_flags(ff_custom_compliance_frameworks: custom_framework_flag)
         stub_licensed_features(compliance_framework: feature_enabled)
         enable_admin_mode!(current_user) if admin_mode
       end