Fix “Share lock” policy for deeply nested groups

app/policies/group_policy.rb

@@ -16,7 +16,7 @@ class GroupPolicy < BasePolicy
   condition(:nested_groups_supported, scope: :global) { Group.supports_nested_groups? }
 
   condition(:parent_share_locked) { @subject.has_parent? && @subject.parent.share_with_group_lock? }
-  condition(:parent_owner) { @subject.has_parent? && @subject.parent.has_owner?(@user) }
+  condition(:can_change_parent_share_with_group_lock) { @subject.has_parent? && can?(:change_share_with_group_lock, @subject.parent) }
 
   condition(:has_projects) do
     GroupProjectsFinder.new(group: @subject, current_user: @user).execute.any?
@@ -57,7 +57,7 @@ class GroupPolicy < BasePolicy
   rule { ~can?(:view_globally) }.prevent   :request_access
   rule { has_access }.prevent              :request_access
 
-  rule { owner & (~parent_share_locked | parent_owner) }.enable :change_share_with_group_lock
+  rule { owner & (~parent_share_locked | can_change_parent_share_with_group_lock) }.enable :change_share_with_group_lock
 
   def access_level
     return GroupMember::NO_ACCESS if @user.nil?

spec/policies/group_policy_spec.rb

@@ -248,9 +248,34 @@ describe GroupPolicy do
       let(:group) { create(:group, parent: parent) }
 
       context 'when the parent share_with_group_lock is enabled' do
-        let(:parent) { create(:group, share_with_group_lock: true) }
         let(:current_user) { owner }
 
+        context 'when the group has a grandparent' do
+          let(:grandparent) { create(:group, share_with_group_lock: true) }
+          let(:parent) { create(:group, share_with_group_lock: true, parent: grandparent) }
+
+          context 'and the grandparent share_with_group_lock is enabled' do
+            context 'when current_user owns the grandparent' do
+              before do
+                grandparent.add_owner(owner)
+              end
+
+              it { expect_allowed(:change_share_with_group_lock) }
+            end
+
+            context 'when current_user owns the parent but not the grandparent' do
+              before do
+                parent.add_owner(owner)
+              end
+
+              it { expect_disallowed(:change_share_with_group_lock) }
+            end
+          end
+        end
+
+        context 'when the group does not have a grandparent' do
+          let(:parent) { create(:group, share_with_group_lock: true) }
+
           context 'when current_user owns the parent' do
             before do
               parent.add_owner(owner)
@@ -263,6 +288,7 @@ describe GroupPolicy do
             it { expect_disallowed(:change_share_with_group_lock) }
           end
         end
+      end
 
       context 'when the parent share_with_group_lock is disabled' do
         let(:parent) { create(:group) }