[INFO] cloning repository https://github.com/fmosbacher/mathematician
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fmosbacher/mathematician" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffmosbacher%2Fmathematician", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffmosbacher%2Fmathematician'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 561e816499a3697e09020b62d0f537ba9ff864ad
[INFO] checking fmosbacher/mathematician against master#5337252b9952fdd9482ed6a4add17254e5bd2c40 for pr-138785
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffmosbacher%2Fmathematician" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] [stderr] error: Unable to create '/workspace/builds/worker-5-tc1/source/.git/refs/remotes/origin/HEAD.lock': No such file or directory
[INFO] [stderr] fatal: unable to update refs/remotes/origin/HEAD


failed to checkout https://github.com/fmosbacher/mathematician

Caused by:
    command failed: exit status: 128