[INFO] cloning repository https://github.com/usagrada/mdbook-ruby
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/usagrada/mdbook-ruby" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fusagrada%2Fmdbook-ruby", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fusagrada%2Fmdbook-ruby'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a3b5b0017a1bc2a1fe2228c3b1db34b358339312
[INFO] checking usagrada/mdbook-ruby against master#ecb170afc878648c3ae355dbd596c8e4b6f7ebdc for pr-139022
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fusagrada%2Fmdbook-ruby" "/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/usagrada/mdbook-ruby

Caused by:
    command failed: exit status: 128