rustAsync race conditionMedium

Async function causes MutexGuard error during await

Time: 0:00

BugFind the bug and fix the code

What it should do

Process data asynchronously and update a shared resource. Example: process_async_data(data) -> ()

What happens instead

error[E0277]: ?Sized + 'static is not satisfied

use std::sync::{Arc, Mutex};
use tokio::task;

struct SharedResource {
    data: String,
}

async fn process_async_data(resource: Arc<Mutex<SharedResource>>) {
    let mut guard = resource.lock().unwrap();
    task::spawn(async move {
        guard.data.push_str(" processed");
    }).await.unwrap();
}

#[tokio::main]
async fn main() {
    let resource = Arc::new(Mutex::new(SharedResource { data: String::from("data") }));
    process_async_data(resource).await;
    println!("{:#?}", resource.lock().unwrap().data);
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

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This bug belongs to the async and race conditions pattern

A missing await, unbuffered channel deadlocks, ConcurrentModificationException, and data races under load.

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use std::sync::{Arc, Mutex}; use tokio::task; struct SharedResource { data: String, } async fn process_async_data(resource: Arc<Mutex<SharedResource>>) { let mut guard = resource.lock().unwrap(); task::spawn(async move { guard.data.push_str(" processed"); }).await.unwrap(); } #[tokio::main] async fn main() { let resource = Arc::new(Mutex::new(SharedResource { data: String::from("data") })); process_async_data(resource).await; println!("{:#?}", resource.lock().unwrap().data); }

Async function causes MutexGuard error during await

What it should do

What happens instead

More async and race conditions to practise

Async function causes MutexGuard error during await

What it should do

What happens instead

More async and race conditions to practise