rust/tests/ui/await_holding_lock.rs
flip1995 cdf9a28006
Improve lint message of await_holding_*
Improves the message of the lints await_holding_lock and
await_holding_refcell_ref. Now also actually tests RwLock.
2022-02-17 18:00:40 +01:00

89 lines
1.6 KiB
Rust

#![warn(clippy::await_holding_lock)]
use std::sync::{Mutex, RwLock};
async fn bad(x: &Mutex<u32>) -> u32 {
let guard = x.lock().unwrap();
baz().await
}
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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}
async fn baz() -> u32 {
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}
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
}
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)]
fn block_bad(x: &Mutex<u32>) -> impl std::future::Future<Output = u32> + '_ {
async move {
let guard = x.lock().unwrap();
baz().await
}
}
fn main() {
let m = Mutex::new(100);
good(&m);
bad(&m);
also_bad(&m);
not_good(&m);
block_bad(&m);
}