[INFO] cloning repository https://github.com/kloki/advent-of-code-2015
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kloki/advent-of-code-2015" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkloki%2Fadvent-of-code-2015", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkloki%2Fadvent-of-code-2015'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1d94cd8b7271483e47d244c0f39488afccb7e7c6
[INFO] testing kloki/advent-of-code-2015 against master#414482f6a0d4e7290f614300581a0b55442552a3 for pr-140985
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkloki%2Fadvent-of-code-2015" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] error: failed to write new configuration file /workspace/builds/worker-6-tc1/source/.git/config.lock
[INFO] [stderr] fatal: could not set 'core.repositoryformatversion' to '0'


failed to checkout https://github.com/kloki/advent-of-code-2015

Caused by:
    command failed: exit status: 128