Merge branch 'prevent-creating-multiple-application-settings' into 'master'

Prevent creating multiple ApplicationSetting by forcing it to always have id=1

Closes #34728

See merge request gitlab-org/gitlab-ce!14718

(cherry picked from commit 65a1cbc600cf36ff5db9644072e4bf1e2b8e5cde)

c909b6aa Prevent creating multiple ApplicationSetting by forcing it to always have id=1

3 files changed, 17 insertions, 0 deletions

diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index c0cc60d5ebf..5b5bb3cbe2c 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -33,6 +33,8 @@ class ApplicationSetting < ActiveRecord::Base
 
   attr_accessor :domain_whitelist_raw, :domain_blacklist_raw
 
+  default_value_for :id, 1
+
   validates :uuid, presence: true
 
   validates :session_expire_delay,
diff --git a/changelogs/unreleased/prevent-creating-multiple-application-settings.yml b/changelogs/unreleased/prevent-creating-multiple-application-settings.yml
new file mode 100644
index 00000000000..fd49028b9e9
--- /dev/null
+++ b/changelogs/unreleased/prevent-creating-multiple-application-settings.yml
@@ -0,0 +1,5 @@
+---
+title: Prevent creating multiple ApplicationSetting instances
+merge_request:
+author:
+type: fixed
diff --git a/spec/models/application_setting_spec.rb b/spec/models/application_setting_spec.rb
index 78cacf9ff5d..eff84c308b5 100644
--- a/spec/models/application_setting_spec.rb
+++ b/spec/models/application_setting_spec.rb
@@ -209,6 +209,16 @@ describe ApplicationSetting do
     end
   end
 
+  context 'restrict creating duplicates' do
+    before do
+      described_class.create_from_defaults
+    end
+
+    it 'raises an record creation violation if already created' do
+      expect { described_class.create_from_defaults }.to raise_error(ActiveRecord::RecordNotUnique)
+    end
+  end
+
   context 'restricted signup domains' do
     it 'sets single domain' do
       setting.domain_whitelist_raw = 'example.com'