[INFO] cloning repository https://github.com/keitaroskmt/matroid_bandits
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/keitaroskmt/matroid_bandits" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkeitaroskmt%2Fmatroid_bandits", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkeitaroskmt%2Fmatroid_bandits'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3edb682fdb60f8083c61b650e9ec34bbf7eab762
[INFO] testing keitaroskmt/matroid_bandits against master#7704328ba5ae8d6ce0ac303c9d5a1a1605906766 for pr-146989
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkeitaroskmt%2Fmatroid_bandits" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] [stderr] error: Unable to create '/workspace/builds/worker-6-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/keitaroskmt/matroid_bandits

Caused by:
    command failed: exit status: 128