Bisect with `--timeout` panics on Mac

[jruderman]

Trying to use the --timeout flag on Mac causes the bisector to panic:

$ RUST_BACKTRACE=1 cargo-bisect-rustc --start=2022-10-03 --preserve --timeout 5

checking the start range to find a passing nightly
installing nightly-2022-10-03
testing...
thread 'main' panicked at 'thiserror::Errored to run "timeout" "5" "cargo" "+bisector-nightly-2022-10-03-x86_64-apple-darwin" "build": Os { code: 2, kind: NotFound, message: "No such file or directory" }', /Users/*/.cargo/registry/src/github.com-1ecc6299db9ec823/cargo-bisect-rustc-0.6.4/src/toolchains.rs:302:17
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

I believe cargo-bisect-rustc is assuming the presence of a utility called timeout that is common on Linux but not on Mac. The --timeout feature was added in PR #135 (@savente93, @ehuss).

Version

$ cargo-bisect-rustc --version
cargo-bisect-rustc 0.6.4

[savente93]

I don't have access to a mac so this is not something I can diagnose. However I imagine adding a conditional cfg on line

cargo-bisect-rustc/src/toolchains.rs

Line 260 in c7a4b84

let mut cmd = Command::new("timeout");

to use a more appropriate tool should be enough

[LingMan]

Switching to the wait-timeout crate might also be an option.

[kornelski]

macOS doesn't ship with a timeout command. I'm surprised this is implemented using a CLI tool, rather than a timeout in Rust.

Here's a workaround:

brew install coreutils