Skip to content

Document cancel-safety of FuturesUnordered::poll_next #2897

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Document cancel-safety of FuturesUnordered::poll_next #2897

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
8a75b98
Document cancel-safety of FuturesUnordered::poll_next
akonradi-signal Nov 13, 2024
ea5b0ea
Conditionalize cancel-safety on Future cancel safety
akonradi-signal Dec 2, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 7 additions & 0 deletions futures-util/src/stream/futures_unordered/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,13 @@ use self::ready_to_run_queue::{Dequeue, ReadyToRunQueue};
///
/// This type is only available when the `std` or `alloc` feature of this
/// library is activated, and it is activated by default.
///
/// # Cancel safety
///
/// This type is cancellation-safe. If [`poll_next`](Stream::poll_next) is
Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is it cancellation-safe independent of the inner type?

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good question. I think not; if the inner future type F shouldn't be dropped before it resolves, then a FuturesUnordered<F> shouldn't be dropped before it's empty. I'll update the PR.

/// called (either directly or via [`crate::StreamExt::next`]) and it returns
/// [`Poll::Pending`], no values will be dropped if `poll_next` is not called
/// again.
#[must_use = "streams do nothing unless polled"]
pub struct FuturesUnordered<Fut> {
ready_to_run_queue: Arc<ReadyToRunQueue<Fut>>,
Expand Down