[INFO] cloning repository https://github.com/halfzebra/rust-smart-pointers-examples
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/halfzebra/rust-smart-pointers-examples" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhalfzebra%2Frust-smart-pointers-examples", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhalfzebra%2Frust-smart-pointers-examples'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d0f57ba42e7466e89ac79f06a9ce5a0f97765967
[INFO] checking halfzebra/rust-smart-pointers-examples against master#2886b36df4a646dd8d82fb65bf0c9d8d96c1f71a for pr-145113
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhalfzebra%2Frust-smart-pointers-examples" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-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-4-tc1/source/.git/refs/heads/master.lock'


failed to checkout https://github.com/halfzebra/rust-smart-pointers-examples

Caused by:
    command failed: exit status: 128