[INFO] updating cached repository https://github.com/rust-lang-nursery/rustup.rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] [stderr] From https://github.com/rust-lang-nursery/rustup.rs
[INFO] [stderr]    c19b43cb..138d33e5  master     -> master
[INFO] [stderr]  + 2fa36ddb...2d019878 stable     -> stable  (forced update)
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 138d33e501899946bdab38c7af161d6ec24c1601
[ERROR] this task or one of its parent failed!
[ERROR] command `Command { std: "/workspace/cargo-home/bin/cargo" "+394e1b40d264aa6928811919c1124fa248e7d802" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }` failed
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.