Make maintainers the default setting for creating subgroups

app/models/group.rb

@@ -58,6 +58,8 @@ class Group < Namespace
 
   add_authentication_token_field :runners_token, encrypted: -> { Feature.enabled?(:groups_tokens_optional_encryption, default_enabled: true) ? :optional : :required }
 
+  before_create :default_subgroup_creation_level_to_maintainers
+
   after_create :post_create_hook
   after_destroy :post_destroy_hook
   after_save :update_two_factor_requirement
@@ -416,10 +418,6 @@ class Group < Namespace
     super || ::Gitlab::CurrentSettings.default_project_creation
   end
 
-  def subgroup_creation_level
-    super || ::Gitlab::Access::MAINTAINER_SUBGROUP_ACCESS
-  end
-
   private
 
   def update_two_factor_requirement
@@ -449,4 +447,8 @@ class Group < Namespace
 
     errors.add(:visibility_level, "#{visibility} is not allowed since there are sub-groups with higher visibility.")
   end
+
+  def default_subgroup_creation_level_to_maintainers
+    self.subgroup_creation_level = ::Gitlab::Access::MAINTAINER_SUBGROUP_ACCESS
+  end
 end

spec/models/group_spec.rb

@@ -994,4 +994,12 @@ describe Group do
       expect(group.project_creation_level).to eq(Gitlab::CurrentSettings.default_project_creation)
     end
   end
+
+  describe 'subgroup_creation_level' do
+    it 'defaults to maintainers' do
+      group = create (:group)
+
+      expect(group.subgroup_creation_level).to eq(Gitlab::Access::MAINTAINER_SUBGROUP_ACCESS)
+    end
+  end
 end