util: enable loom tests (#7644)

Co-authored-by: Benjamin Ran <[email protected]>

tokio-util/src/either.rs

@@ -212,7 +212,7 @@ where
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(loom)))]
 mod tests {
     use super::*;
     use tokio::io::{repeat, AsyncReadExt, Repeat};

tokio-util/src/loom.rs

@@ -1 +1,9 @@
-pub(crate) use std::sync;
+//! This module abstracts over `loom` and `std::sync` types depending on whether we
+//! are running loom tests or not.
+
+pub(crate) mod sync {
+    #[cfg(all(test, loom))]
+    pub(crate) use loom::sync::{Arc, Mutex, MutexGuard};
+    #[cfg(not(all(test, loom)))]
+    pub(crate) use std::sync::{Arc, Mutex, MutexGuard};
+}

tokio-util/src/net/mod.rs

@@ -1,3 +1,5 @@
+#![cfg(not(loom))]
+
 //! TCP/UDP/Unix helpers for tokio.
 
 use crate::either::Either;

tokio-util/src/sync/mod.rs

@@ -15,3 +15,6 @@ pub use poll_semaphore::PollSemaphore;
 
 mod reusable_box;
 pub use reusable_box::ReusableBoxFuture;
+
+#[cfg(test)]
+mod tests;

tokio-util/src/sync/tests/loom_cancellation_token.rs

@@ -100,6 +100,9 @@ fn drop_token_no_child() {
     });
 }
 
+// Temporarily disabled due to a false positive in loom -
+// see https://github.com/tokio-rs/tokio/pull/7644#issuecomment-3328381344
+#[ignore]
 #[test]
 fn drop_token_with_children() {
     loom::model(|| {
@@ -125,6 +128,9 @@ fn drop_token_with_children() {
     });
 }
 
+// Temporarily disabled due to a false positive in loom -
+// see https://github.com/tokio-rs/tokio/pull/7644#issuecomment-3328381344
+#[ignore]
 #[test]
 fn drop_and_cancel_token() {
     loom::model(|| {
@@ -150,6 +156,9 @@ fn drop_and_cancel_token() {
     });
 }
 
+// Temporarily disabled due to a false positive in loom -
+// see https://github.com/tokio-rs/tokio/pull/7644#issuecomment-3328381344
+#[ignore]
 #[test]
 fn cancel_parent_and_child() {
     loom::model(|| {

tokio-util/src/sync/tests/mod.rs

@@ -1 +1,2 @@
-
+#[cfg(loom)]
+mod loom_cancellation_token;

tokio-util/src/udp/mod.rs

@@ -1,3 +1,5 @@
+#![cfg(not(loom))]
+
 //! UDP framing
 
 mod frame;