hls-runtime 0.8.0

//! Proof that the deadline-bounded runner fixes the `Command::output()` hang:
//! a stub tool forks a sleeping grandchild that holds stdout/stderr, then
//! exits at once. `output()` blocks until the grandchild dies; the bounded
//! runner returns as soon as the tool itself exits.
#![cfg(unix)]

use test_bounded::output_bounded;

use std::process::Command;
use std::time::{Duration, Instant};

/// How long the stub's grandchild keeps the pipes open.
const GRANDCHILD_SLEEP_SECS: u64 = 6;
/// Window within which the pipe-based `output()` must still be blocked.
const OUTPUT_BLOCK_WINDOW: Duration = Duration::from_secs(2);
/// Deadline handed to the bounded runner.
const DEADLINE: Duration = Duration::from_secs(4);

/// A command that runs `body` through `sh -c`. No file is ever written, so
/// there is no write-then-exec ETXTBSY ("text file busy") race between
/// parallel test threads, and no temp directory is left behind.
fn stub(body: &str) -> Command {
    let mut cmd = Command::new("/bin/sh");
    cmd.arg("-c").arg(body);
    cmd
}

fn leaky_stub() -> Command {
    stub(&format!(
        "sleep {GRANDCHILD_SLEEP_SECS} &\necho hello\nexit 0"
    ))
}

#[test]
fn pipe_based_output_hangs_on_a_pipe_holding_grandchild() {
    let mut tool = leaky_stub();
    let (tx, rx) = std::sync::mpsc::channel();
    std::thread::spawn(move || {
        let out = tool.output().expect("spawn");
        let _ = tx.send(out);
    });
    assert!(
        rx.recv_timeout(OUTPUT_BLOCK_WINDOW).is_err(),
        "output() was expected to block on the grandchild-held pipe"
    );
}

#[test]
fn bounded_runner_returns_despite_pipe_holding_grandchild() {
    let mut tool = leaky_stub();
    let start = Instant::now();
    let out = output_bounded(&mut tool, DEADLINE).expect("run");
    assert!(out.status.success());
    assert_eq!(out.stdout, b"hello\n");
    assert!(
        start.elapsed() < Duration::from_secs(GRANDCHILD_SLEEP_SECS),
        "returned only after the grandchild exited: {:?}",
        start.elapsed()
    );
}

#[test]
fn bounded_runner_kills_an_overrunning_tool_with_a_clear_error() {
    let mut tool = stub("exec sleep 30");
    let start = Instant::now();
    let err = output_bounded(&mut tool, Duration::from_millis(300)).expect_err("must time out");
    assert_eq!(err.kind(), std::io::ErrorKind::TimedOut);
    assert!(err.to_string().contains("/bin/sh"), "{err}");
    assert!(err.to_string().contains("hard deadline"), "{err}");
    assert!(start.elapsed() < Duration::from_secs(5));
}