1 files changed, 21 insertions, 0 deletions
diff --git a/third_party/rust/rayon/tests/cross-pool.rs b/third_party/rust/rayon/tests/cross-pool.rs
new file mode 100644
index 0000000000..f0a2128a77
--- /dev/null
+++ b/third_party/rust/rayon/tests/cross-pool.rs
@@ -0,0 +1,21 @@
+use rayon::prelude::*;
+use rayon::ThreadPoolBuilder;
+
+#[test]
+fn cross_pool_busy() {
+    let pool1 = ThreadPoolBuilder::new().num_threads(1).build().unwrap();
+    let pool2 = ThreadPoolBuilder::new().num_threads(1).build().unwrap();
+
+    let n: i32 = 100;
+    let sum: i32 = pool1.install(move || {
+        // Each item will block on pool2, but pool1 can continue processing other work from the
+        // parallel iterator in the meantime. There's a chance that pool1 will still be awake to
+        // see the latch set without being tickled, and then it will drop that stack job. The latch
+        // internals must not assume that the job will still be alive after it's set!
+        (1..=n)
+            .into_par_iter()
+            .map(|i| pool2.install(move || i))
+            .sum()
+    });
+    assert_eq!(sum, n * (n + 1) / 2);
+}