Fix importers not assigning a new default group

The Bitbucket Server as well as other importers pass in a group name to be
created (assuming the user has permission) and attempt to dedupe that with an
existing group. However, the group *name* is not guaranteed to be
unique, but the *path* is.

Closes #50110

app/helpers/namespaces_helper.rb

@@ -55,7 +55,7 @@ module NamespacesHelper
   # group if one exists by that name to prevent duplicates.
   def dedup_extra_group(extra_group)
     unless extra_group.persisted?
-      existing_group = Group.find_by(name: extra_group.name)
+      existing_group = Group.find_by(path: extra_group.path)
       extra_group = existing_group if existing_group&.persisted?
     end
 

changelogs/unreleased/sh-fix-dedupe-group-importer.yml

+---
+title: Fix importers not assigning a new default group
+merge_request: 21456
+author:
+type: fixed

spec/helpers/namespaces_helper_spec.rb

@@ -50,9 +50,12 @@ describe NamespacesHelper do
     end
 
     it 'selects the new group by default' do
+      # Ensure we don't select a group with the same name
+      create(:group, name: 'new-group', path: 'another-path')
+
       allow(helper).to receive(:current_user).and_return(user)
 
-      options = helper.namespaces_options(:extra_group, display_path: true, extra_group: build(:group, name: 'new-group'))
+      options = helper.namespaces_options(:extra_group, display_path: true, extra_group: build(:group, name: 'new-group', path: 'new-group'))
 
       expect(options).to include(user_group.name)
       expect(options).not_to include(admin_group.name)