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#![warn(clippy::await_holding_lock)]
// When adding or modifying a test, please do the same for parking_lot::Mutex.
mod std_mutex {
use super::baz;
use std::sync::{Mutex, RwLock};
pub async fn bad(x: &Mutex<u32>) -> u32 {
let guard = x.lock().unwrap();
baz().await
}
pub async fn good(x: &Mutex<u32>) -> u32 {
{
let guard = x.lock().unwrap();
let y = *guard + 1;
}
baz().await;
let guard = x.lock().unwrap();
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}
pub async fn bad_rw(x: &RwLock<u32>) -> u32 {
let guard = x.read().unwrap();
baz().await
}
pub async fn bad_rw_write(x: &RwLock<u32>) -> u32 {
let mut guard = x.write().unwrap();
baz().await
}
pub async fn good_rw(x: &RwLock<u32>) -> u32 {
{
let guard = x.read().unwrap();
let y = *guard + 1;
}
{
let mut guard = x.write().unwrap();
*guard += 1;
}
baz().await;
let guard = x.read().unwrap();
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}
pub async fn also_bad(x: &Mutex<u32>) -> u32 {
let first = baz().await;
let guard = x.lock().unwrap();
let second = baz().await;
let third = baz().await;
first + second + third
}
pub async fn not_good(x: &Mutex<u32>) -> u32 {
let first = baz().await;
let second = {
let guard = x.lock().unwrap();
baz().await
};
let third = baz().await;
first + second + third
}
#[allow(clippy::manual_async_fn)]
pub fn block_bad(x: &Mutex<u32>) -> impl std::future::Future<Output = u32> + '_ {
async move {
let guard = x.lock().unwrap();
baz().await
}
}
}
// When adding or modifying a test, please do the same for std::Mutex.
mod parking_lot_mutex {
use super::baz;
use parking_lot::{Mutex, RwLock};
pub async fn bad(x: &Mutex<u32>) -> u32 {
let guard = x.lock();
baz().await
}
pub async fn good(x: &Mutex<u32>) -> u32 {
{
let guard = x.lock();
let y = *guard + 1;
}
baz().await;
let guard = x.lock();
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}
pub async fn bad_rw(x: &RwLock<u32>) -> u32 {
let guard = x.read();
baz().await
}
pub async fn bad_rw_write(x: &RwLock<u32>) -> u32 {
let mut guard = x.write();
baz().await
}
pub async fn good_rw(x: &RwLock<u32>) -> u32 {
{
let guard = x.read();
let y = *guard + 1;
}
{
let mut guard = x.write();
*guard += 1;
}
baz().await;
let guard = x.read();
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}
pub async fn also_bad(x: &Mutex<u32>) -> u32 {
let first = baz().await;
let guard = x.lock();
let second = baz().await;
let third = baz().await;
first + second + third
}
pub async fn not_good(x: &Mutex<u32>) -> u32 {
let first = baz().await;
let second = {
let guard = x.lock();
baz().await
};
let third = baz().await;
first + second + third
}
#[allow(clippy::manual_async_fn)]
pub fn block_bad(x: &Mutex<u32>) -> impl std::future::Future<Output = u32> + '_ {
async move {
let guard = x.lock();
baz().await
}
}
}
async fn baz() -> u32 {
42
}
async fn no_await(x: std::sync::Mutex<u32>) {
let mut guard = x.lock().unwrap();
*guard += 1;
}
// FIXME: FP, because the `MutexGuard` is dropped before crossing the await point. This is
// something the needs to be fixed in rustc. There's already drop-tracking, but this is currently
// disabled, see rust-lang/rust#93751. This case isn't picked up by drop-tracking though. If the
// `*guard += 1` is removed it is picked up.
async fn dropped_before_await(x: std::sync::Mutex<u32>) {
let mut guard = x.lock().unwrap();
*guard += 1;
drop(guard);
baz().await;
}
fn main() {
let m = std::sync::Mutex::new(100);
std_mutex::good(&m);
std_mutex::bad(&m);
std_mutex::also_bad(&m);
std_mutex::not_good(&m);
std_mutex::block_bad(&m);
let m = parking_lot::Mutex::new(100);
parking_lot_mutex::good(&m);
parking_lot_mutex::bad(&m);
parking_lot_mutex::also_bad(&m);
parking_lot_mutex::not_good(&m);
}
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