removes `export_designs` feature flags from ee files

closes #32535

* removes ee/project_tree_restorer and documentation line calling out incomplete support since they are no longer needed
* removes remove_feature_dependent_sub_relations method from project_tree_restorer

changelogs/unreleased/backstage-remove-export-designs-feature-flag.yml

+---
+title: Removes `export_designs` feature flag
+merge_request: 18507
+author: nate geslin
+type: other

doc/user/project/issues/design_management.md

@@ -38,8 +38,6 @@ to be enabled:
 - Files uploaded must have a file extension of either `png`, `jpg`, `jpeg`, `gif`, `bmp`, `tiff` or `ico`.
   The [`svg` extension is not yet supported](https://gitlab.com/gitlab-org/gitlab/issues/12771).
 - Design uploads are limited to 10 files at a time.
-- Design Management is
-  [not yet supported in the project export](https://gitlab.com/gitlab-org/gitlab/issues/11090).
 - Design Management data
   [isn't deleted when a project is destroyed](https://gitlab.com/gitlab-org/gitlab/issues/13429) yet.
 - Design Management data [won't be moved](https://gitlab.com/gitlab-org/gitlab/issues/13426)

ee/app/services/ee/projects/import_export/export_service.rb

@@ -12,8 +12,6 @@ module EE::Projects::ImportExport::ExportService
   end
 
   def design_repo_saver
-    return unless Feature.enabled?(:export_designs, project, default_enabled: true)
-
     Gitlab::ImportExport::DesignRepoSaver.new(project: project, shared: shared)
   end
 end

ee/lib/ee/gitlab/import_export/importer.rb

@@ -12,8 +12,6 @@ module EE::Gitlab::ImportExport::Importer
   end
 
   def design_repo_restorer
-    return unless Feature.enabled?(:export_designs, project, default_enabled: true)
-
     Gitlab::ImportExport::DesignRepoRestorer.new(
       path_to_bundle: design_repo_path,
       shared: shared,

ee/lib/ee/gitlab/import_export/project_tree_restorer.rb

-# frozen_string_literal: true
-
-module EE
-  module Gitlab
-    module ImportExport
-      module ProjectTreeRestorer
-        extend ActiveSupport::Concern
-        extend ::Gitlab::Utils::Override
-
-        private
-
-        override :remove_feature_dependent_sub_relations!
-        def remove_feature_dependent_sub_relations!(relation_item)
-          export_designs_disabled = ::Feature.disabled?(:export_designs, project, default_enabled: true)
-
-          if relation_item.is_a?(Hash) && export_designs_disabled
-            relation_item.except!('designs', 'design_versions')
-          end
-        end
-      end
-    end
-  end
-end

ee/spec/lib/ee/gitlab/import_export/project_tree_restorer_spec.rb

@@ -17,7 +17,6 @@ describe Gitlab::ImportExport::ProjectTreeRestorer do
   end
 
   describe 'restoring design management data' do
-    context 'when the `export_designs` feature is enabled' do
     before do
       restored_project_json
     end
@@ -65,27 +64,4 @@ describe Gitlab::ImportExport::ProjectTreeRestorer do
       end
     end
   end
-
-    context 'when the `export_designs` feature is disabled' do
-      before do
-        stub_feature_flags(export_designs: false)
-
-        restored_project_json
-      end
-
-      it_behaves_like 'restores project correctly', issues: 2
-
-      it 'does not restore any Designs' do
-        expect(DesignManagement::Design).not_to exist
-      end
-
-      it 'does not restore any Versions' do
-        expect(DesignManagement::Version.exists?).to be false
-      end
-
-      it 'does not restore any DesignVersions' do
-        expect(DesignManagement::Action.exists?).to be false
-      end
-    end
-  end
 end

ee/spec/lib/gitlab/import_export/importer_spec.rb

@@ -29,17 +29,5 @@ describe Gitlab::ImportExport::Importer do
 
       importer.execute
     end
-
-    context 'when the `export_designs` feature is disabled' do
-      before do
-        stub_feature_flags(export_designs: false)
-      end
-
-      it 'does not restore the design repo' do
-        expect(Gitlab::ImportExport::DesignRepoRestorer).not_to receive(:new)
-
-        importer.execute
-      end
-    end
   end
 end

ee/spec/services/projects/import_export/export_service_spec.rb

@@ -15,17 +15,5 @@ describe Projects::ImportExport::ExportService do
 
       service.execute
     end
-
-    context 'when the `export_designs` feature is disabled' do
-      before do
-        stub_feature_flags(export_designs: false)
-      end
-
-      it 'does not save the design repo' do
-        expect(Gitlab::ImportExport::DesignRepoSaver).not_to receive(:new)
-
-        service.execute
-      end
-    end
   end
 end

lib/gitlab/import_export/project_tree_restorer.rb

@@ -120,10 +120,6 @@ module Gitlab
         end
       end
 
-      def remove_feature_dependent_sub_relations!(_relation_item)
-        # no-op
-      end
-
       def project_relations
         @project_relations ||= reader.attributes_finder.find_relations_tree(:project)
       end
@@ -175,8 +171,6 @@ module Gitlab
 
         # Avoid keeping a possible heavy object in memory once we are done with it
         while relation_item = tree_array.shift
-          remove_feature_dependent_sub_relations!(relation_item)
-
           # The transaction at this level is less speedy than one single transaction
           # But we can't have it in the upper level or GC won't get rid of the AR objects
           # after we save the batch.
@@ -241,5 +235,3 @@ module Gitlab
     end
   end
 end
-
-Gitlab::ImportExport::ProjectTreeRestorer.prepend_if_ee('::EE::Gitlab::ImportExport::ProjectTreeRestorer')