[INFO] cloning repository https://github.com/dskydiver/tic_tac_toe
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/dskydiver/tic_tac_toe" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdskydiver%2Ftic_tac_toe", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdskydiver%2Ftic_tac_toe'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 370808f8709ce104d0d88fd98e8c025ca7627ef9
[INFO] checking dskydiver/tic_tac_toe against master#e3e432d4d65a55e6db167598e96db2bcb163e316 for pr-140313
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdskydiver%2Ftic_tac_toe" "/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/dskydiver/tic_tac_toe

Caused by:
    command failed: exit status: 128