Fix visibility level error when updating group from API

'visibility_level' private is not allowed since this group contains projects with higher visibility

Fixes: #23083

Related: gitlab-foss#46746

app/services/groups/create_service.rb

@@ -9,6 +9,7 @@ module Groups
 
     def execute
       remove_unallowed_params
+      set_visibility_level
 
       @group = Group.new(params)
 
@@ -68,6 +69,12 @@ module Groups
 
       true
     end
+
+    def set_visibility_level
+      return if visibility_level.present?
+
+      params[:visibility_level] = Gitlab::CurrentSettings.current_application_settings.default_group_visibility
+    end
   end
 end
 

changelogs/unreleased/group_default_visibility.yml

+---
+title: Fix visibility level error when updating group from API
+merge_request: 17227
+author: Mathieu Parent
+type: fixed

lib/api/helpers/groups_helpers.rb

@@ -10,8 +10,6 @@ module API
         optional :description, type: String, desc: 'The description of the group'
         optional :visibility, type: String,
                  values: Gitlab::VisibilityLevel.string_values,
-                 default: Gitlab::VisibilityLevel.string_level(
-                   Gitlab::CurrentSettings.current_application_settings.default_group_visibility),
                  desc: 'The visibility of the group'
         optional :lfs_enabled, type: Boolean, desc: 'Enable/disable LFS for the projects in this group'
         optional :request_access_enabled, type: Boolean, desc: 'Allow users to request member access'