[INFO] cloning repository https://github.com/vicsn/round_cache_test
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/vicsn/round_cache_test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvicsn%2Fround_cache_test", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvicsn%2Fround_cache_test'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 227eadec2b0f6b6b9d6d58c5fb4834a5802f8526
[INFO] checking vicsn/round_cache_test against master#f8c27dfe1a2e7fb538fd91dad53de06992c7c967 for pr-138915
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvicsn%2Fround_cache_test" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] [stderr] fatal: update_ref failed for ref 'HEAD': cannot update ref 'refs/heads/master': couldn't write '/workspace/builds/worker-7-tc1/source/.git/refs/heads/master.lock'


failed to checkout https://github.com/vicsn/round_cache_test

Caused by:
    command failed: exit status: 128