[INFO] updating cached repository https://github.com/rust-lang-nursery/rustup.rs
[INFO] running `"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"`
[INFO] [stderr] From https://github.com/rust-lang-nursery/rustup.rs
[INFO] [stderr]    8e03e74e..72bea7b3  master     -> master
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 72bea7b31cc2c04c1920d016142a4f862c532736
[ERROR] this task or one of its parent failed!
[ERROR] command `"/workspace/cargo-home/bin/cargo" "+212aa3ea28d91a97d1e1261709c0b6e6790788e6" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.