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Tracking Issue for JoinHandle::is_finished #90470
Description
Feature gate: #![feature(thread_is_running)]
Public API
impl<T> JoinHandle<T> {
pub fn is_finshed(&self) -> bool;
}Steps / History
- Implementation: Add JoinHandle::is_running. #90439
-
First Final comment period (FCP): Tracking Issue for JoinHandle::is_finished #90470 (comment) - Rename it to
is_finished: Rename JoinHandle::is_running to is_finished. #94549 - Final comment period (FCP): Tracking Issue for JoinHandle::is_finished #90470 (comment)
- Stabilization PR: Stabilize thread::is_finished #95130
Unresolved Questions
- Do we also want to provide a way to access the result of the thread without having to .join() it? See Add JoinHandle::is_running. #90439 (comment)
- Answer: Maybe, but not a blocker for this feature.
- Do we also want this in the form of a Future? See Add JoinHandle::is_running. #90439 (comment)
- Answer: Maybe, but not a blocker for this feature.
- Name it
is_finishedinstead?- Answer: Yes.
Reacted by Chris West, kkocdko, Calandiel, Justin Kilpatrick, Felipe de Luca Andrea and wu aoxiang
Reacted by kkocdko and Justin Kilpatrick
Activity
m-ou-se commentedon Feb 15, 2022
I think the unresolved questions above can be ideas for future additions, but aren't blockers for this API.
@rfcbot merge
rfcbot commentedon Feb 15, 2022
Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members:
No concerns currently listed.
Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!
See this document for info about what commands tagged team members can give me.
joshtriplett commentedon Feb 15, 2022
I feel like the comment on the PR about
try_join(ignoring any naming questions) seemed right: the use case for this seems like "check is_running and then immediately join, but don't block for any appreciable amount of time".That said, the type signature (
fn try_join(self) -> Result<..., Self>would be annoying to deal with in practice, and it doesn't seem like a good idea to make it work with&selfinstead.Given those constraints, this seems like a reasonable API. However, I think I'm going to submit a PR for the documentation, to steer people away from tight-polling on it, and document the intended use case.
@rfcbot reviewed
joshtriplett commentedon Feb 15, 2022
#94033
rfcbot commentedon Feb 16, 2022
🔔 This is now entering its final comment period, as per the review above. 🔔
workingjubilee commentedon Feb 20, 2022
Hm. At the risk of getting philosophical, what does it mean for a thread to be "running", if this would return
truewhen the thread is sleeping?And did this get answered in the negative?
Amanieu commentedon Feb 20, 2022
I think the question that you are usually asking is "has this thread finished running" rather than "is this thread still running". Perhaps this function could be inverted and renamed to "is_finished"?
workingjubilee commentedon Feb 21, 2022
While an async method was decided against, I will note Poll uses the idiom
is_readyoris_pending.Julian-Wollersberger commentedon Feb 24, 2022
+1 for @Amanieu's suggestion.
Since the intended use case is more or less
if !is_running() { join() }, it would be clearer to invert the function name:if is_finished() { join() }36 remaining items
m-ou-se commentedon Mar 9, 2022
Let's try again with the new name. Now it's
is_finished()rather thanis_running(). That removes any ambiguity when the thread is sleeping or blocked (not 'running' (depending on your definition), but still not finished).@rfcbot merge
rfcbot commentedon Mar 9, 2022
Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members:
No concerns currently listed.
Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!
See this document for info about what commands tagged team members can give me.
rfcbot commentedon Mar 9, 2022
🔔 This is now entering its final comment period, as per the review above. 🔔
rfcbot commentedon Mar 19, 2022
The final comment period, with a disposition to merge, as per the review above, is now complete.
As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.
This will be merged soon.
Rollup merge of rust-lang#95130 - workingjubilee:stably-finished, r=m…
Rollup merge of rust-lang#95130 - workingjubilee:stably-finished, r=m…