Add `Poll::ready` and revert stabilization of `task::ready!` #89651

ibraheemdev · 2021-10-07T22:15:55Z

This PR adds an inherent ready method to Poll that can be used with the ? operator as an alternative to the task::ready! macro:

let val = ready!(fut.poll(cx));
let val = fut.poll(cx).ready()?;

I think this form is a nice, non-breaking middle ground between changing the impl Try for Poll, and adding a separate macro. It looks better than ready! in my opinion, and it composes well:

let elem = ready!(fut.poll(cx)).pop().unwrap();
let elem = fut.poll(cx).ready()?.pop().unwrap();

The planned stabilization of ready! in 1.56 has been reverted because I think this alternate approach is worth considering.

r? rust-lang/libs

tmandry · 2021-10-08T01:16:10Z

This is quite nice. Worth considering at least.

camelid · 2021-10-08T02:40:38Z

(Just noting that 1.56 release notes would likely need to be updated.)

Mark-Simulacrum · 2021-10-08T02:48:19Z

Please note that if you choose to revert things landing in 1.56, the timeline on that is quite short -- ideally PRs for that are merged into master and tagged with beta-nominated + beta-accepted by mid-next week -- we have just 2 weeks before the release must ship.

dtolnay · 2021-10-08T02:57:18Z

@rfcbot poll libs-api Retract ready! stabilization from 1.56.0?

rfcbot · 2021-10-08T02:57:19Z

Team member @dtolnay has asked teams: T-libs-api, for consensus on:

Retract ready! stabilization from 1.56.0?

joshtriplett · 2021-10-09T02:16:54Z

While I don't see much harm in having both, this does seem better in every way.

yaahc · 2021-10-11T17:53:29Z

While I don't see much harm in having both, this does seem better in every way.

I think there's a distinct disadvantage to having both, insofar as I think it's generally more confusing and difficult to teach features or functionality that can be invoked in multiple different ways. Not to mention the needless style discussions it ends up causing downstream where users often end up wanting to standardize on one option or the other.

dtolnay · 2021-10-11T19:21:14Z

@bors r+
@rustbot label +beta-nominated

Nominating only the 2nd and 3rd commit (5f7e7d2 + 7a7dfa8) to be backported.

bors · 2021-10-11T19:21:16Z

📌 Commit a1e03fc has been approved by dtolnay

Add `Poll::ready` and revert stabilization of `task::ready!` This PR adds an inherent `ready` method to `Poll` that can be used with the `?` operator as an alternative to the `task::ready!` macro: ```rust let val = ready!(fut.poll(cx)); let val = fut.poll(cx).ready()?; ``` I think this form is a nice, non-breaking middle ground between changing the `impl Try for Poll`, and adding a separate macro. It looks better than `ready!` in my opinion, and it composes well: ```rust let elem = ready!(fut.poll(cx)).pop().unwrap(); let elem = fut.poll(cx).ready()?.pop().unwrap(); ``` The planned stabilization of `ready!` in 1.56 has been reverted because I think this alternate approach is worth considering. r? rust-lang/libs

…askrgr Rollup of 9 pull requests Successful merges: - rust-lang#89471 (Use Ancestory to check default fn in const impl instead of comparing idents) - rust-lang#89643 (Fix inherent impl overlap check.) - rust-lang#89651 (Add `Poll::ready` and revert stabilization of `task::ready!`) - rust-lang#89675 (Re-use TypeChecker instead of passing around some of its fields ) - rust-lang#89710 (Add long explanation for error E0482) - rust-lang#89756 (Greatly reduce amount of debuginfo compiled for bootstrap itself) - rust-lang#89760 (Remove hack ignoring unused attributes for stage 0 std) - rust-lang#89772 (Fix function-names test for GDB 10.1) - rust-lang#89785 (Fix ICE when compiling nightly std/rustc on beta compiler) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

…htriplett fix minor spelling error in Poll::ready docs Fixes minor spelling error in the proposed `Poll::ready` docs. Not that my opinion matters, but +1 on the original PR (rust-lang#89651), it reads much nicer to me than the `ready!` macro.

m-ou-se · 2021-10-12T11:38:31Z

Beta-accepted based on #89651 (comment)

Note for whoever end up backporting this: Only commits 5f7e7d2 and 7a7dfa8 should be backported, as David noted above.

…htriplett fix minor spelling error in Poll::ready docs Fixes minor spelling error in the proposed `Poll::ready` docs. Not that my opinion matters, but +1 on the original PR (rust-lang#89651), it reads much nicer to me than the `ready!` macro.

[beta] backports - 2229: Consume IfLet expr rust-lang#89282 - Wrapper for -Z gcc-ld=lld to invoke rust-lld with the correct flavor rust-lang#89288 - Fix unsound optimization with explicit variant discriminants rust-lang#89489 - Fix stabilization version for bindings_after_at rust-lang#89605 - Turn vtable_allocation() into a query rust-lang#89619 - Revert "Stabilize Iterator::intersperse()" rust-lang#89638 - Ignore type of projections for upvar capturing rust-lang#89648 - ~~Add Poll::ready and~~ revert stabilization of task::ready! rust-lang#89651 - CI: Use mirror for libisl downloads for more docker dist builds rust-lang#89661 - Use correct edition for panic in [debug_]assert!(). rust-lang#89622 - Switch to our own mirror of libisl plus ct-ng oldconfig fixes rust-lang#89599 - Emit item no type error even if type inference fails rust-lang#89585 - Revert enum discriminants rust-lang#89884

add Poll::ready

a57c18b

rust-highfive assigned dtolnay Oct 7, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 7, 2021

ibraheemdev changed the title ~~Add Poll::ready~~ Add Poll::ready and revert stabilization of task::ready! Oct 7, 2021

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ibraheemdev force-pushed the poll-ready branch from 5786931 to 5f7e7d2 Compare October 7, 2021 22:42

revert stabilization of core::task::ready!

5f7e7d2

dtolnay added the T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. label Oct 8, 2021

Remove task::ready! from 1.56.0 release notes

7a7dfa8

dtolnay mentioned this pull request Oct 11, 2021

Tracking Issue for poll.ready()? #89780

Closed

Add library tracking issue for poll_ready feature

a1e03fc

dtolnay approved these changes Oct 11, 2021

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rustbot added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Oct 11, 2021

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 11, 2021

matthiaskrgr mentioned this pull request Oct 11, 2021

Rollup of 10 pull requests #89783

Closed

matthiaskrgr mentioned this pull request Oct 11, 2021

Rollup of 9 pull requests #89791

Merged

bors merged commit d3984e1 into rust-lang:master Oct 12, 2021

rustbot added this to the 1.57.0 milestone Oct 12, 2021

dtolnay mentioned this pull request Oct 12, 2021

Tracking Issue for core::task::ready! macro #70922

Closed

8 tasks

ast-ral mentioned this pull request Oct 12, 2021

fix minor spelling error in Poll::ready docs #89799

Merged

m-ou-se added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Oct 12, 2021

cuviper mentioned this pull request Oct 13, 2021

[beta] backports #89854

Merged

cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Oct 13, 2021

cuviper modified the milestones: 1.57.0, 1.56.0 Oct 13, 2021

robjtede mentioned this pull request Dec 4, 2021

move ready_macro back to unstable jplatte/caniuse.rs#40

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Add `Poll::ready` and revert stabilization of `task::ready!` #89651

Add `Poll::ready` and revert stabilization of `task::ready!` #89651

ibraheemdev commented Oct 7, 2021 •

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Add Poll::ready and revert stabilization of task::ready! #89651

Add Poll::ready and revert stabilization of task::ready! #89651

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Add `Poll::ready` and revert stabilization of `task::ready!` #89651

Add `Poll::ready` and revert stabilization of `task::ready!` #89651

ibraheemdev commented Oct 7, 2021 •

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