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//@ run-pass
//@ check-run-results
//@ needs-subprocess
//@ ignore-windows
//@ ignore-fuchsia
//@ ignore-horizon
//@ ignore-android
//@ ignore-ios no 'head'
//@ ignore-tvos no 'head'
//@ ignore-watchos no 'head'
//@ ignore-visionos no 'head'
//@ ignore-backends: gcc
//@ normalize-stderr: ".rs:\d+:\d+" -> ".rs:LL:CC"
//@ compile-flags: -Zon-broken-pipe=error
// Test what the error message looks like when `println!()` panics because of
// `std::io::ErrorKind::BrokenPipe`
use std::env;
use std::process::{Command, Stdio};
fn main() {
let mut args = env::args();
let me = args.next().unwrap();
if let Some(arg) = args.next() {
// More than enough iterations to fill any pipe buffer. Normally this
// loop will end with a panic more or less immediately.
for _ in 0..65536 * 64 {
println!("{arg}");
}
unreachable!("should have panicked because of BrokenPipe");
}
// Set up a pipeline with a short-lived consumer and wait for it to finish.
// This will produce the `println!()` panic message on stderr.
let mut producer = Command::new(&me)
.arg("this line shall appear exactly once on stdout")
.env("RUST_BACKTRACE", "0")
.stdout(Stdio::piped())
.spawn()
.unwrap();
let mut consumer =
Command::new("head").arg("-n1").stdin(producer.stdout.take().unwrap()).spawn().unwrap();
consumer.wait().unwrap();
producer.wait().unwrap();
}
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