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use rayon::prelude::*;
use rayon::ThreadPoolBuilder;
use std::ops::Range;
use std::panic::{self, UnwindSafe};
use std::sync::atomic::{AtomicUsize, Ordering};
const ITER: Range<i32> = 0..0x1_0000;
const PANIC: i32 = 0xC000;
fn check(&i: &i32) {
if i == PANIC {
panic!("boom")
}
}
#[test]
#[should_panic(expected = "boom")]
fn iter_panic() {
ITER.into_par_iter().for_each(|i| check(&i));
}
#[test]
fn iter_panic_fuse() {
// We only use a single thread in order to make the behavior
// of 'panic_fuse' deterministic
let pool = ThreadPoolBuilder::new().num_threads(1).build().unwrap();
pool.install(|| {
fn count(iter: impl ParallelIterator + UnwindSafe) -> usize {
let count = AtomicUsize::new(0);
let result = panic::catch_unwind(|| {
iter.for_each(|_| {
count.fetch_add(1, Ordering::Relaxed);
});
});
assert!(result.is_err());
count.into_inner()
}
// Without `panic_fuse()`, we'll reach every item except the panicking one.
let expected = ITER.len() - 1;
let iter = ITER.into_par_iter().with_max_len(1);
assert_eq!(count(iter.clone().inspect(check)), expected);
// With `panic_fuse()` anywhere in the chain, we'll reach fewer items.
assert!(count(iter.clone().inspect(check).panic_fuse()) < expected);
assert!(count(iter.clone().panic_fuse().inspect(check)) < expected);
// Try in reverse to be sure we hit the producer case.
assert!(count(iter.panic_fuse().inspect(check).rev()) < expected);
});
}