diff --git a/tokio/CHANGELOG.md b/tokio/CHANGELOG.md index b748408e088..68e2af6583f 100644 --- a/tokio/CHANGELOG.md +++ b/tokio/CHANGELOG.md @@ -1,3 +1,11 @@ +# 0.2.16 (April 3, 2020) + +### Fixes + +- sync: fix a regression where `Mutex`, `Semaphore`, and `RwLock` futures no + longer implement `Sync` (#2375) + + # 0.2.15 (April 2, 2020) ### Fixes diff --git a/tokio/Cargo.toml b/tokio/Cargo.toml index 31bf3271213..9fd5f95de6f 100644 --- a/tokio/Cargo.toml +++ b/tokio/Cargo.toml @@ -8,12 +8,12 @@ name = "tokio" # - README.md # - Update CHANGELOG.md. # - Create "v0.2.x" git tag. -version = "0.2.15" +version = "0.2.16" edition = "2018" authors = ["Tokio Contributors "] license = "MIT" readme = "README.md" -documentation = "https://docs.rs/tokio/0.2.15/tokio/" +documentation = "https://docs.rs/tokio/0.2.16/tokio/" repository = "https://github.com/tokio-rs/tokio" homepage = "https://tokio.rs" description = """ diff --git a/tokio/src/lib.rs b/tokio/src/lib.rs index 7db4cb3045f..d0cb5fa4230 100644 --- a/tokio/src/lib.rs +++ b/tokio/src/lib.rs @@ -1,4 +1,4 @@ -#![doc(html_root_url = "https://docs.rs/tokio/0.2.15")] +#![doc(html_root_url = "https://docs.rs/tokio/0.2.16")] #![allow( clippy::cognitive_complexity, clippy::large_enum_variant, diff --git a/tokio/src/sync/batch_semaphore.rs b/tokio/src/sync/batch_semaphore.rs index 5d15311da0c..436737a6709 100644 --- a/tokio/src/sync/batch_semaphore.rs +++ b/tokio/src/sync/batch_semaphore.rs @@ -463,6 +463,13 @@ impl Drop for Acquire<'_> { } } +// Safety: the `Acquire` future is not `Sync` automatically because it contains +// a `Waiter`, which, in turn, contains an `UnsafeCell`. However, the +// `UnsafeCell` is only accessed when the future is borrowed mutably (either in +// `poll` or in `drop`). Therefore, it is safe (although not particularly +// _useful_) for the future to be borrowed immutably across threads. +unsafe impl Sync for Acquire<'_> {} + // ===== impl AcquireError ==== impl AcquireError { diff --git a/tokio/src/sync/mutex.rs b/tokio/src/sync/mutex.rs index dac5ac16c42..6b51b405681 100644 --- a/tokio/src/sync/mutex.rs +++ b/tokio/src/sync/mutex.rs @@ -137,8 +137,15 @@ impl Error for TryLockError {} fn bounds() { fn check_send() {} fn check_unpin() {} + // This has to take a value, since the async fn's return type is unnameable. + fn check_send_sync_val(_t: T) {} + fn check_send_sync() {} check_send::>(); check_unpin::>(); + check_send_sync::>(); + + let mutex = Mutex::new(1); + check_send_sync_val(mutex.lock()); } impl Mutex { diff --git a/tokio/src/sync/rwlock.rs b/tokio/src/sync/rwlock.rs index 7cce69a5c5d..0f7991a5bf8 100644 --- a/tokio/src/sync/rwlock.rs +++ b/tokio/src/sync/rwlock.rs @@ -133,6 +133,9 @@ fn bounds() { fn check_send() {} fn check_sync() {} fn check_unpin() {} + // This has to take a value, since the async fn's return type is unnameable. + fn check_send_sync_val(_t: T) {} + check_send::>(); check_sync::>(); check_unpin::>(); @@ -142,6 +145,10 @@ fn bounds() { check_sync::>(); check_unpin::>(); + + let rwlock = RwLock::new(0); + check_send_sync_val(rwlock.read()); + check_send_sync_val(rwlock.write()); } // As long as T: Send + Sync, it's fine to send and share RwLock between threads. diff --git a/tokio/src/sync/semaphore.rs b/tokio/src/sync/semaphore.rs index e34e49cc7fe..4cce7e8f5bc 100644 --- a/tokio/src/sync/semaphore.rs +++ b/tokio/src/sync/semaphore.rs @@ -39,8 +39,15 @@ pub struct TryAcquireError(()); #[cfg(not(loom))] fn bounds() { fn check_unpin() {} + // This has to take a value, since the async fn's return type is unnameable. + fn check_send_sync_val(_t: T) {} + fn check_send_sync() {} check_unpin::(); check_unpin::>(); + check_send_sync::(); + + let semaphore = Semaphore::new(0); + check_send_sync_val(semaphore.acquire()); } impl Semaphore {