[INFO] cloning repository https://github.com/redwarp/Advent-of-Code-2019
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/redwarp/Advent-of-Code-2019" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fredwarp%2FAdvent-of-Code-2019", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fredwarp%2FAdvent-of-Code-2019'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6d5b0b058aa03954fbf81629c1fef5375c5343da
[INFO] checking redwarp/Advent-of-Code-2019 against master#03eb45452305f2d52348279d0caa5fc1f12c438d for pr-138176
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fredwarp%2FAdvent-of-Code-2019" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-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-2-tc1/source/.git/refs/heads/master.lock'


failed to checkout https://github.com/redwarp/Advent-of-Code-2019

Caused by:
    command failed: exit status: 128