rustAsync race conditionHard

Channel receiver hangs due to retained sender clone

Time: 0:00

BugFind the bug and fix the code

What it should do

Send items through mpsc channel and collect all into vector. Example: drain_sync_channel(2) -> [1, 2]

What happens instead

Receiver loop hangs forever waiting for items because original tx was never dropped

use std::sync::mpsc;
use std::thread;

fn drain_sync_channel(count: i32) -> Vec<i32> {
    let (tx, rx) = mpsc::channel();
    let tx1 = tx.clone();
    thread::spawn(move || {
        for i in 1..=count {
            tx1.send(i).unwrap();
        }
    });
    // Main thread still holds original tx, so rx never sees channel close!
    let mut results = vec![];
    for msg in rx {
        results.push(msg);
    }
    results
}

fn main() {
    println!("{:?}", drain_sync_channel(2));
}

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

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Hint 3

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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::mpsc; use std::thread; fn drain_sync_channel(count: i32) -> Vec<i32> { let (tx, rx) = mpsc::channel(); let tx1 = tx.clone(); thread::spawn(move || { for i in 1..=count { tx1.send(i).unwrap(); } }); // Main thread still holds original tx, so rx never sees channel close! let mut results = vec![]; for msg in rx { results.push(msg); } results } fn main() { println!("{:?}", drain_sync_channel(2)); }

Channel receiver hangs due to retained sender clone

What it should do

What happens instead

More async and race conditions to practise

Channel receiver hangs due to retained sender clone

What it should do

What happens instead

More async and race conditions to practise