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Unexpected panics when using async functions with tokio in Rust core project

👀 Views: 65 đŸ’Ŧ Answers: 1 📅 Created: 2025-05-31
rust tokio async-await Rust

I'm working with an scenario with my Rust application that uses the tokio runtime. Specifically, I'm getting unexpected panics when I try to execute an async function that interacts with a shared state. The panic occurs intermittently, and I suspect it might be related to how I manage the state across different tasks. Here's a simplified version of my code: ```rust use std::sync::{Arc, Mutex}; use tokio::task; struct SharedState { counter: usize, } #[tokio::main] async fn main() { let state = Arc::new(Mutex::new(SharedState { counter: 0 })); let mut handles = vec![]; for _ in 0..10 { let state_clone = Arc::clone(&state); let handle = task::spawn(async move { for _ in 0..100 { let mut lock = state_clone.lock().unwrap(); lock.counter += 1; } }); handles.push(handle); } for handle in handles { handle.await.unwrap(); } println!("Final counter: {}", state.lock().unwrap().counter); } ``` I've tried wrapping the `lock()` calls with behavior handling to catch potential issues like the mutex being poisoned, but the panics still happen. The behavior message I see is often `thread 'tokio-runtime-worker' panicked at 'called `Option::unwrap()` on a `None` value'`. This indicates that I might be accessing something that is not initialized correctly, but I need to find where the scenario lies. I also checked that the `tokio` version I'm using is 1.0.0. Could this be a question with the way I'm structuring my async tasks, or is there a better way to handle shared state in a concurrent environment? Any insights or suggestions would be greatly appreciated!