Convert upgrade link experiment to feature flag [RUN ALL RSPEC] [RUN AS-IF-FOSS]

ee/config/feature_flags/experiment/upgrade_link_in_user_menu_a_experiment_percentage.yml → config/feature_flags/development/upgrade_link_in_user_menu_a.yml

 ---
-name: upgrade_link_in_user_menu_a_experiment_percentage
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/29428
-rollout_issue_url: https://gitlab.com/gitlab-org/growth/team-tasks/-/issues/126
-milestone: '13.0'
-type: experiment
+name: upgrade_link_in_user_menu_a
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/56591
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/300824
+milestone: '13.11'
+type: development
 group: group::expansion
-default_enabled: false
+default_enabled: true

ee/app/helpers/ee/users_helper.rb

@@ -23,7 +23,7 @@ module EE
     def show_upgrade_link?(user)
       return unless user
       return unless ::Gitlab.com?
-      return unless experiment_enabled?(:upgrade_link_in_user_menu_a)
+      return unless ::Feature.enabled?(:upgrade_link_in_user_menu_a, default_enabled: :yaml)
 
       Rails.cache.fetch(['users', user.id, 'show_upgrade_link?'], expires_in: 10.minutes) do
         user.owns_upgradeable_namespace?

ee/changelogs/unreleased/300824-experiment-cleanup-upgrade_link_in_user_menu_a.yml

+---
+title: Add upgrade link in user menu
+merge_request: 56591
+author:
+type: added

lib/gitlab/experimentation.rb

@@ -34,10 +34,6 @@
 module Gitlab
   module Experimentation
     EXPERIMENTS = {
-      upgrade_link_in_user_menu_a: {
-        tracking_category: 'Growth::Expansion::Experiment::UpgradeLinkInUserMenuA',
-        use_backwards_compatible_subject_index: true
-      },
       invite_members_version_b: {
         tracking_category: 'Growth::Expansion::Experiment::InviteMembersVersionB',
         use_backwards_compatible_subject_index: true

spec/lib/gitlab/experimentation_spec.rb

@@ -7,7 +7,6 @@ require 'spec_helper'
 RSpec.describe Gitlab::Experimentation::EXPERIMENTS do
   it 'temporarily ensures we know what experiments exist for backwards compatibility' do
     expected_experiment_keys = [
-      :upgrade_link_in_user_menu_a,
       :invite_members_version_b,
       :invite_members_empty_group_version_a,
       :contact_sales_btn_in_app