Stabilize slice_sort_by_cached_key #58074

scottmcm · 2019-02-02T09:11:14Z

I was going to ask on the tracking issue (#34447), but decided to just send this and hope for an FCP here. The method was added last March by #48639.

Signature: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by_cached_key

impl [T] {
    pub fn sort_by_cached_key<K, F>(&mut self, f: F)
        where F: FnMut(&T) -> K, K: Ord;
}

That's an identical signature to the existing sort_by_key, so I think the questions are just naming, implementation, and the usual "do we want this?".

The implementation seems to have proven its use in rustc at least, which many uses: https://github.com/rust-lang/rust/search?l=Rust&q=sort_by_cached_key

(I'm asking because it's exactly what I just needed the other day:

    all_positions.sort_by_cached_key(|&n|
        data::CITIES.iter()
            .map(|x| *metric_closure.get_edge(n, x.pos).unwrap())
            .sum::<usize>()
    );

since caching that key is a pretty obviously good idea.)

Closes #34447

scottmcm · 2019-02-02T09:14:00Z

Since this is needs-fcp, it needs someone from libs. Since they've p-FCP'd things recently, how about

r? @SimonSapin

SimonSapin · 2019-02-02T10:08:00Z

@rfcbot fcp merge

rfcbot · 2019-02-02T10:08:00Z

Team member @SimonSapin 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 none object), 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.

SimonSapin · 2019-02-02T10:08:37Z

r+ on the diff, good to merge once FCP is finished.

rfcbot · 2019-02-05T09:20:50Z

🔔 This is now entering its final comment period, as per the review above. 🔔

…cumentation" This reverts commit 9c7b69e.

rfcbot · 2019-02-15T09:23:11Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

scottmcm · 2019-02-15T09:23:47Z

@bors r=SimonSapin

bors · 2019-02-15T09:23:47Z

📌 Commit 317f153 has been approved by SimonSapin

bors · 2019-02-15T19:44:28Z

⌛ Testing commit 317f153 with merge 8bfe6ce9efdee35fadb833e90a5a019d68446c0e...

bors · 2019-02-15T19:48:18Z

💔 Test failed - checks-travis

rust-highfive · 2019-02-15T19:48:19Z

Your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

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pietroalbini · 2019-02-15T20:23:04Z

@bors retry -- apparently we can't clone the repo anymore on macOS

…ey, r=SimonSapin Stabilize slice_sort_by_cached_key I was going to ask on the tracking issue (rust-lang#34447), but decided to just send this and hope for an FCP here. The method was added last March by rust-lang#48639. Signature: https://doc.rust-lang.org/std/primitive.slice.html#method.sort_by_cached_key ```rust impl [T] { pub fn sort_by_cached_key<K, F>(&mut self, f: F) where F: FnMut(&T) -> K, K: Ord; } ``` That's an identical signature to the existing `sort_by_key`, so I think the questions are just naming, implementation, and the usual "do we want this?". The implementation seems to have proven its use in rustc at least, which many uses: https://github.com/rust-lang/rust/search?l=Rust&q=sort_by_cached_key (I'm asking because it's exactly what I just needed the other day: ```rust all_positions.sort_by_cached_key(|&n| data::CITIES.iter() .map(|x| *metric_closure.get_edge(n, x.pos).unwrap()) .sum::<usize>() ); ``` since caching that key is a pretty obviously good idea.) Closes rust-lang#34447

Rollup of 19 pull requests Successful merges: - #57929 (Rustdoc remove old style files) - #57981 (Fix #57730) - #58074 (Stabilize slice_sort_by_cached_key) - #58196 (Add specific feature gate error for const-unstable features) - #58293 (Remove code for updating copyright years in generate-deriving-span-tests) - #58306 (Don't default on std crate when manipulating browser history) - #58359 (librustc_mir: use ? in impl_snapshot_for! macro) - #58395 (Instant::checked_duration_since) - #58429 (fix Box::into_unique effecitvely transmuting to a raw ptr) - #58433 (Update which libcore/liballoc tests Miri ignores, and document why) - #58438 (Use posix_spawn_file_actions_addchdir_np when possible) - #58440 (Whitelist the ARM v6 target-feature) - #58448 (rustdoc: mask `compiler_builtins` docs) - #58468 (split MaybeUninit into several features, expand docs a bit) - #58477 (Fix the syntax error in publish_toolstate.py) - #58479 (compile-pass test for #53606) - #58489 (Fix runtime error in generate-keyword-tests) - #58496 (Fix documentation for std::path::PathBuf::pop) - #58509 (Notify myself when Clippy toolstate changes)

Rollup of 19 pull requests Successful merges: - #57929 (Rustdoc remove old style files) - #57981 (Fix #57730) - #58074 (Stabilize slice_sort_by_cached_key) - #58196 (Add specific feature gate error for const-unstable features) - #58293 (Remove code for updating copyright years in generate-deriving-span-tests) - #58306 (Don't default on std crate when manipulating browser history) - #58359 (librustc_mir: use ? in impl_snapshot_for! macro) - #58395 (Instant::checked_duration_since) - #58429 (fix Box::into_unique effecitvely transmuting to a raw ptr) - #58433 (Update which libcore/liballoc tests Miri ignores, and document why) - #58438 (Use posix_spawn_file_actions_addchdir_np when possible) - #58440 (Whitelist the ARM v6 target-feature) - #58448 (rustdoc: mask `compiler_builtins` docs) - #58468 (split MaybeUninit into several features, expand docs a bit) - #58479 (compile-pass test for #53606) - #58489 (Fix runtime error in generate-keyword-tests) - #58496 (Fix documentation for std::path::PathBuf::pop) - #58509 (Notify myself when Clippy toolstate changes) - #58521 (Fix tracking issue for error iterators)

scottmcm added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. needs-fcp This change is insta-stable, so needs a completed FCP to proceed. labels Feb 2, 2019

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rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Feb 2, 2019

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rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Feb 5, 2019

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scottmcm added 2 commits February 12, 2019 22:26

Stabilize slice_sort_by_cached_key

3777b86

Revert "Remove mentions of unstable sort_by_cached key from stable do…

317f153

…cumentation" This reverts commit 9c7b69e.

scottmcm force-pushed the stabilize-sort_by_cached_key branch from 2827922 to 317f153 Compare February 13, 2019 06:27

rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Feb 15, 2019

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-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). labels Feb 15, 2019

kennytm mentioned this pull request Feb 15, 2019

Rollup of 19 pull requests #58495

Merged

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Feb 15, 2019

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 Feb 15, 2019

bors merged commit 317f153 into rust-lang:master Feb 17, 2019

scottmcm deleted the stabilize-sort_by_cached_key branch February 18, 2019 00:17

Centril added this to the 1.34 milestone Apr 27, 2019

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Stabilize slice_sort_by_cached_key #58074

Stabilize slice_sort_by_cached_key #58074

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Stabilize slice_sort_by_cached_key #58074

Stabilize slice_sort_by_cached_key #58074

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