Add the container_expiration_policies_historic_entry feature flag

Projects marked by this feature flag are allowed to have a container
expiration policy

app/helpers/container_expiration_policies_helper.rb

@@ -24,4 +24,9 @@ module ContainerExpirationPoliciesHelper
       end
     end
   end
+
+  def container_expiration_policies_historic_entry_enabled?(project)
+    Gitlab::CurrentSettings.container_expiration_policies_enable_historic_entries ||
+      Feature.enabled?(:container_expiration_policies_historic_entry, project)
+  end
 end

app/views/projects/registry/settings/_index.haml

@@ -5,4 +5,4 @@
     older_than_options: older_than_options.to_json,
     is_admin: current_user&.admin.to_s,
     admin_settings_path: ci_cd_admin_application_settings_path(anchor: 'js-registry-settings'),
-    enable_historic_entries: Gitlab::CurrentSettings.try(:container_expiration_policies_enable_historic_entries).to_s} }
+    enable_historic_entries: container_expiration_policies_historic_entry_enabled?(@project).to_s} }

changelogs/unreleased/244050-feature-flag-to-allow-old-projects-to-have-a-cleanup-policy.yml

+---
+title: Add feature flag for a phased rollout of cleanup policies
+merge_request: 44444
+author:
+type: added

config/feature_flags/development/container_expiration_policies_historic_entry.yml

+---
+name: container_expiration_policies_historic_entry
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/44444
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/262639
+type: development
+group: group::package
+default_enabled: false

doc/user/packages/container_registry/index.md

@@ -469,6 +469,20 @@ Cleanup policies can be run on all projects, with these exceptions:
 
   There are performance risks with enabling it for all projects, especially if you
   are using an [external registry](./index.md#use-with-external-container-registries).
+- For self-managed GitLab instances, you can enable or disable the cleanup policy for a specific
+  project.
+
+  To enable it:
+
+  ```ruby
+  Feature.enable(:container_expiration_policies_historic_entry, Project.find(<project id>))
+  ```
+
+  To disable it:
+
+  ```ruby
+  Feature.disable(:container_expiration_policies_historic_entry, Project.find(<project id>))
+  ```
 
 ### How the cleanup policy works
 

spec/features/projects/settings/registry_settings_spec.rb

@@ -3,27 +3,35 @@
 require 'spec_helper'
 
 RSpec.describe 'Project > Settings > CI/CD > Container registry tag expiration policy', :js do
-  let(:user) { create(:user) }
-  let(:project) { create(:project, namespace: user.namespace, container_registry_enabled: container_registry_enabled) }
+  using RSpec::Parameterized::TableSyntax
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project, reload: true) { create(:project, namespace: user.namespace) }
+
   let(:container_registry_enabled) { true }
+  let(:container_registry_enabled_on_project) { true }
+
+  subject { visit project_settings_ci_cd_path(project) }
 
   before do
+    project.update!(container_registry_enabled: container_registry_enabled_on_project)
+
     sign_in(user)
-    stub_container_registry_config(enabled: true)
+    stub_container_registry_config(enabled: container_registry_enabled)
     stub_feature_flags(new_variables_ui: false)
   end
 
   context 'as owner' do
-    before do
-      visit project_settings_ci_cd_path(project)
-    end
-
     it 'shows available section' do
+      subject
+
       settings_block = find('#js-registry-policies')
       expect(settings_block).to have_text 'Cleanup policy for tags'
     end
 
     it 'saves cleanup policy submit the form' do
+      subject
+
       within '#js-registry-policies' do
         within '.card-body' do
           select('7 days until tags are automatically removed', from: 'Expiration interval:')
@@ -40,6 +48,8 @@ RSpec.describe 'Project > Settings > CI/CD > Container registry tag expiration p
     end
 
     it 'does not save cleanup policy submit form with invalid regex' do
+      subject
+
       within '#js-registry-policies' do
         within '.card-body' do
           fill_in('Tags with names matching this regex pattern will expire:', with: '*-production')
@@ -53,25 +63,53 @@ RSpec.describe 'Project > Settings > CI/CD > Container registry tag expiration p
     end
   end
 
-  context 'when registry is disabled' do
-    before do
-      stub_container_registry_config(enabled: false)
-      visit project_settings_ci_cd_path(project)
+  context 'with a project without expiration policy' do
+    where(:application_setting, :feature_flag, :result) do
+      true  | true  | :available_section
+      true  | false | :available_section
+      false | true  | :available_section
+      false | false | :disabled_message
     end
 
-    it 'does not exists' do
-      expect(page).not_to have_selector('#js-registry-policies')
+    with_them do
+      before do
+        project.container_expiration_policy.destroy!
+        stub_feature_flags(container_expiration_policies_historic_entry: false)
+        stub_application_setting(container_expiration_policies_enable_historic_entries: application_setting)
+        stub_feature_flags(container_expiration_policies_historic_entry: project) if feature_flag
+      end
+
+      it 'displays the expected result' do
+        subject
+
+        within '#js-registry-policies' do
+          case result
+          when :available_section
+            expect(find('.card-header')).to have_content('Tag expiration policy')
+          when :disabled_message
+            expect(find('.gl-alert-title')).to have_content('Cleanup policy for tags is disabled')
+          end
+        end
+      end
     end
   end
 
-  context 'when container registry is disabled on project' do
+  context 'when registry is disabled' do
     let(:container_registry_enabled) { false }
 
-    before do
-      visit project_settings_ci_cd_path(project)
+    it 'does not exists' do
+      subject
+
+      expect(page).not_to have_selector('#js-registry-policies')
     end
+  end
+
+  context 'when container registry is disabled on project' do
+    let(:container_registry_enabled_on_project) { false }
 
     it 'does not exists' do
+      subject
+
       expect(page).not_to have_selector('#js-registry-policies')
     end
   end

spec/helpers/container_expiration_policies_helper_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 RSpec.describe ContainerExpirationPoliciesHelper do
+  using RSpec::Parameterized::TableSyntax
+
   describe '#keep_n_options' do
     it 'returns keep_n options formatted for dropdown usage' do
       expected_result = [
@@ -44,4 +46,27 @@ RSpec.describe ContainerExpirationPoliciesHelper do
       expect(helper.older_than_options).to eq(expected_result)
     end
   end
+
+  describe '#container_expiration_policies_historic_entry_enabled?' do
+    let_it_be(:project) { build_stubbed(:project) }
+
+    subject { helper.container_expiration_policies_historic_entry_enabled?(project) }
+
+    where(:application_setting, :feature_flag, :expected_result) do
+      true  | true  | true
+      true  | false | true
+      false | true  | true
+      false | false | false
+    end
+
+    with_them do
+      before do
+        stub_feature_flags(container_expiration_policies_historic_entry: false)
+        stub_application_setting(container_expiration_policies_enable_historic_entries: application_setting)
+        stub_feature_flags(container_expiration_policies_historic_entry: project) if feature_flag
+      end
+
+      it { is_expected.to eq(expected_result) }
+    end
+  end
 end