add error

.github/workflows/main.yml

@@ -35,7 +35,7 @@ jobs:
         run: |
           cd ~/${{github.event.pull_request.head.repo.name || github.event.repository.name  }}
           git remote add user_repo  https://github.com/${{ github.repository}}
-          git fetch user_repo
+          git fetch user_repo ${{ github.head_ref || github.ref_name }}
           git checkout -b user_repo/${{ github.head_ref || github.ref_name }}
         shell: bash