`cargo --help` panics when stdout is closed

[lopopolo]

Problem

cargo --help panics when stdout is closed.

There is a discussion about this API papercut upstream: clap-rs/clap#3055.

Steps

$ RUST_BACKTRACE=1 cargo --help | false
thread 'main' panicked at 'Error writing Error to stdout: Os { code: 32, kind: BrokenPipe, message: "Broken pipe" }', /Users/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/clap-2.33.3/src/errors.rs:401:55
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed
   3: core::result::Result<T,E>::expect
   4: clap::errors::Error::exit
   5: cargo::exit_with_error
   6: cargo::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

Possible Solution(s)

Use the App::get_matches_from_safe API and manually handle the error it returns, suppressing failures to write to either stdout or stderr.

Notes

No response

Version

cargo 1.56.0 (4ed5d137b 2021-10-04)
release: 1.56.0
commit-hash: 4ed5d137baff5eccf1bae5a7b2ae4b57efad4a7d
commit-date: 2021-10-04

[weihanglo]

I saw it fixed on clap v2.33.4. Really great!
clap-rs/clap@accf3d2

[ehuss]

Thanks @weihanglo, would you mind posting a PR that updates our Cargo.toml to "2.34.0"?