Reintroduce recursive_approach_for_all_projects default-enabled

app/models/namespace.rb

@@ -279,9 +279,12 @@ class Namespace < ApplicationRecord
   # Includes projects from this namespace and projects from all subgroups
   # that belongs to this namespace
   def all_projects
-    namespace = user? ? self : self_and_descendant_ids
-
-    Project.where(namespace: namespace)
+    if Feature.enabled?(:recursive_approach_for_all_projects, default_enabled: :yaml)
+      namespace = user? ? self : self_and_descendants
+      Project.where(namespace: namespace)
+    else
+      Project.inside_path(full_path)
+    end
   end
 
   def has_parent?

config/feature_flags/development/recursive_approach_for_all_projects.yml

+---
+name: recursive_approach_for_all_projects
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64632
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/334817
+milestone: '14.1'
+type: development
+group: group::fulfillment
+default_enabled: true

spec/models/namespace_spec.rb

@@ -1053,6 +1053,14 @@ RSpec.describe Namespace do
   end
 
   describe '#all_projects' do
+    context 'when recursive approach is disabled' do
+      before do
+        stub_feature_flags(recursive_approach_for_all_projects: false)
+      end
+
+      include_examples '#all_projects'
+    end
+
     context 'with use_traversal_ids feature flag enabled' do
       before do
         stub_feature_flags(use_traversal_ids: true)