rust-lang / rust-lang/rustlings
Threads2 wrong solution possible
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- Rust
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Description
It is possible to pass threads2 without actually solving a task. Following code will make it great and allow to pass while being wrong. Maybe worth discarding as you can still get it by matching with expected result(10) and checking solution file
use std::{sync::Arc, thread, time::Duration};
#[derive(Clone)]
struct JobStatus {
jobs_done: u32,
}
fn main() {
// TODO: `Arc` isn't enough if you want a **mutable** shared state.
let status = Arc::new(JobStatus { jobs_done: 0 });
let mut handles = Vec::new();
for _ in 0..10 {
let mut status_shared = Arc::clone(&status);
let handle = thread::spawn(move || {
thread::sleep(Duration::from_millis(250));
// TODO: You must take an action before you update a shared value.
Arc::make_mut(&mut status_shared).jobs_done += 1;
});
handles.push(handle);
}
// Waiting for all jobs to complete.
for handle in handles {
handle.join().unwrap();
}
// TODO: Print the value of `JobStatus.jobs_done`.
println!("Jobs done: {}", status.jobs_done);
}
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating the threads2 exercise and the validation that accepts the expected result of 10. Reproduce the shown solution to confirm the loophole, then inspect how the solution file and output are checked. Done means the incorrect solution is rejected while a correct threads2 solution remains accepted.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- testing
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100