Fix race cond. in ApplicationSettingImplementation.create_from_defaults

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/models/application_setting.rb

@@ -223,4 +223,11 @@ class ApplicationSetting < ApplicationRecord
     reset_memoized_terms
   end
   after_commit :expire_performance_bar_allowed_user_ids_cache, if: -> { previous_changes.key?('performance_bar_allowed_group_id') }
+
+  def self.create_from_defaults
+    super
+  rescue ActiveRecord::RecordNotUnique
+    # We already have an ApplicationSetting record, so just return it.
+    current_without_cache
+  end
 end

db/fixtures/development/02_application_settings.rb

+# frozen_string_literal: true
+
+puts "Creating the default ApplicationSetting record.".color(:green)
+Gitlab::CurrentSettings.current_application_settings
+
+# Details https://gitlab.com/gitlab-org/gitlab-ce/issues/46241
+puts "Enable hashed storage for every new projects.".color(:green)
+ApplicationSetting.current_without_cache.update!(hashed_storage_enabled: true)
+
+print '.'

db/fixtures/development/02_settings.rb

-# frozen_string_literal: true
-
-# Enable hashed storage, in development mode, for all projects by default.
-Gitlab::Seeder.quiet do
-  ApplicationSetting.create_from_defaults unless ApplicationSetting.current_without_cache
-  ApplicationSetting.current_without_cache.update!(hashed_storage_enabled: true)
-  print '.'
-end

db/fixtures/development/08_settings.rb

-# We want to enable hashed storage for every new project in development
-# Details https://gitlab.com/gitlab-org/gitlab-ce/issues/46241
-Gitlab::Seeder.quiet do
-  ApplicationSetting.create_from_defaults unless ApplicationSetting.current_without_cache
-  ApplicationSetting.current_without_cache.update!(hashed_storage_enabled: true)
-  print '.'
-end

db/fixtures/production/001_application_settings.rb

+# frozen_string_literal: true
+
 puts "Creating the default ApplicationSetting record.".color(:green)
 Gitlab::CurrentSettings.current_application_settings

spec/models/application_setting_spec.rb

@@ -6,6 +6,7 @@ describe ApplicationSetting do
   let(:setting) { described_class.create_from_defaults }
 
   it { include(CacheableAttributes) }
+  it { include(ApplicationSettingImplementation) }
   it { expect(described_class.current_without_cache).to eq(described_class.last) }
 
   it { expect(setting).to be_valid }
@@ -286,12 +287,10 @@ describe ApplicationSetting do
   end
 
   context 'restrict creating duplicates' do
-    before do
-      described_class.create_from_defaults
-    end
+    let!(:current_settings) { described_class.create_from_defaults }
 
-    it 'raises an record creation violation if already created' do
-      expect { described_class.create_from_defaults }.to raise_error(ActiveRecord::RecordNotUnique)
+    it 'returns the current settings' do
+      expect(described_class.create_from_defaults).to eq(current_settings)
     end
   end