deprecate before_exec in favor of unsafe pre_exec #58059

RalfJung · 2019-02-01T18:54:35Z

The language team agreed that before_exec should be unsafe, and leaves the details of a transition plan to the libs team.

Cc @alexcrichton @rust-lang/libs how would you like to proceed?

rust-highfive · 2019-02-01T18:54:39Z

r? @withoutboats

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alexcrichton · 2019-02-01T21:29:02Z

Thanks for this @RalfJung!

In terms of rollout I think we'll want to schedule this to be stabilized in the future when the replacement, pre_exec, is also on the stable channel. I think the rustc_deprecated tag, as written, will start warning immediately on nightly which provides a subpar experience for stable crates that test on all three versions. I'd recommend 1.37.0 because that means the replacement, pre_exec, has baked on stable for a full release.

In the documentation of before_exec, could it also be mentioned that the function, while stable and usable, is scheduled for a future deprecation. Additionally in the documentation for pre_exec in the safety section, I recall there being mentions on the issue about POSIX saying that it's only defined to do async-signal-safe things or something like that, so it may be worth adding language along those lines.

For other small pieces, could the formatting be updated where necessary to account for this change? There's a few argument lists out of sync and the tests aren't quite indented in an idiomatic way.

For the actual name itself and the plan, let's...

@rfcbot fcp merge

rfcbot · 2019-02-01T21:29:03Z

Team member @alexcrichton 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!

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Centril · 2019-02-01T23:18:39Z

r? @alexcrichton

RalfJung · 2019-02-02T10:08:59Z

I think the rustc_deprecated tag, as written, will start warning immediately on nightly which provides a subpar experience for stable crates that test on all three versions. I'd recommend 1.37.0 because that means the replacement, pre_exec, has baked on stable for a full release.

So I should change rustc_deprecated to 1.37.0 but leave the stabilization of pre_exec the way it was? Done.

In the documentation of before_exec, could it also be mentioned that the function, while stable and usable, is scheduled for a future deprecation.

It already says that this is deprecated? I clarified the wording a bit, but I do not understand what you are asking here.

in the documentation for pre_exec in the safety section, I recall there being mentions on the issue about POSIX saying that it's only defined to do async-signal-safe things or something like that, so it may be worth adding language along those lines.

Done.

There's a few argument lists out of sync

I do not see it, what are you referring to?

the tests aren't quite indented in an idiomatic way.

I ran rustfmt.

alexcrichton

So I should change rustc_deprecated to 1.37.0 but leave the stabilization of pre_exec the way it was? Done.

That's at least what I'm led to believe! We can always tweak it if this ends up not being the case.

It already says that this is deprecated?

Er sorry what I mean is to label it as "schedule to be deprecated" as we're going to have a number of months before it's actually deprecated, and I figured it'd be good to head off any confused users asking why it says it's deprecated but it's not actually labled or warned as deprecated yet.

I ran rustfmt.

Thanks!

src/libstd/sys/redox/ext/process.rs

src/libstd/sys/unix/process/process_common.rs

RalfJung · 2019-02-03T07:43:56Z

Er sorry what I mean is to label it as "schedule to be deprecated" as we're going to have a number of months before it's actually deprecated, and I figured it'd be good to head off any confused users asking why it says it's deprecated but it's not actually labled or warned as deprecated yet.

AFAIK this will be labelled as deprecated in the docs even if the version is still in the future. That's the point, actually: so that people read the docs do not add new uses.

So, this shouldn't be confusing.

…n general

rfcbot · 2019-02-05T09:13:30Z

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

alexcrichton · 2019-02-05T09:22:23Z

Ok, r=me when FCP finishes!

rfcbot · 2019-02-15T09:13:42Z

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

bors · 2019-02-15T15:07:00Z

📌 Commit e023403 has been approved by alexcrichton

bors · 2019-02-15T19:40:20Z

⌛ Testing commit e023403 with merge 0f46f6ed3b18be9cc0e2ee2a90472064eca635ee...

bors · 2019-02-15T19:44:17Z

💔 Test failed - checks-travis

pietroalbini · 2019-02-15T20:21:36Z

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

Mark-Simulacrum · 2019-02-20T04:07:58Z

@bors rollup

@alexcrichton

deprecate before_exec in favor of unsafe pre_exec Fixes rust-lang#39575 As per the [lang team decision](rust-lang#39575 (comment)): > The language team agreed that before_exec should be unsafe, and leaves the details of a transition plan to the libs team. Cc @alexcrichton @rust-lang/libs how would you like to proceed?

@alexcrichton

deprecate before_exec in favor of unsafe pre_exec Fixes rust-lang#39575 As per the [lang team decision](rust-lang#39575 (comment)): > The language team agreed that before_exec should be unsafe, and leaves the details of a transition plan to the libs team. Cc @alexcrichton @rust-lang/libs how would you like to proceed?

@alexcrichton

deprecate before_exec in favor of unsafe pre_exec Fixes rust-lang#39575 As per the [lang team decision](rust-lang#39575 (comment)): > The language team agreed that before_exec should be unsafe, and leaves the details of a transition plan to the libs team. Cc @alexcrichton @rust-lang/libs how would you like to proceed?

@ghost

Rollup of 17 pull requests Successful merges: - #57656 (Deprecate the unstable Vec::resize_default) - #58059 (deprecate before_exec in favor of unsafe pre_exec) - #58064 (override `VecDeque::try_rfold`, also update iterator) - #58198 (Suggest removing parentheses surrounding lifetimes) - #58431 (fix overlapping references in BTree) - #58555 (Add a note about 2018e if someone uses `try {` in 2015e) - #58588 (remove a bit of dead code) - #58589 (cleanup macro after 2018 transition) - #58591 (Dedup a rustdoc diagnostic construction) - #58600 (fix small documentation typo) - #58601 (Search for target_triple.json only if builtin target not found) - #58606 (Docs: put Future trait into spotlight) - #58607 (Fixes #58586: Make E0505 erronous example fail for the 2018 edition) - #58615 (miri: explain why we use static alignment in ref-to-place conversion) - #58620 (introduce benchmarks of BTreeSet.intersection) - #58621 (Update miri links) - #58632 (Make std feature list sorted) Failed merges: r? @ghost

Pkgsrc changes: * Bump required rust version to build to 1.33.0. * Adapt patches to changed file locations. * (I worry about 32-bit ports, now that Atomic64 apparently is First-Class; this has been built on NetBSD/amd64 so far) Upstream changes: Version 1.34.0 (2019-04-11) ========================== Language -------- - [You can now use `#[deprecated = "reason"]`][58166] as a shorthand for `#[deprecated(note = "reason")]`. This was previously allowed by mistake but had no effect. - [You can now accept token streams in `#[attr()]`,`#[attr[]]`, and `#[attr{}]` procedural macros.][57367] - [You can now write `extern crate self as foo;`][57407] to import your crate's root into the extern prelude. Compiler -------- - [You can now target `riscv64imac-unknown-none-elf` and `riscv64gc-unknown-none-elf`.][58406] - [You can now enable linker plugin LTO optimisations with `-C linker-plugin-lto`.][58057] This allows rustc to compile your Rust code into LLVM bitcode allowing LLVM to perform LTO optimisations across C/C++ FFI boundaries. - [You can now target `powerpc64-unknown-freebsd`.][57809] Libraries --------- - [The trait bounds have been removed on some of `HashMap<K, V, S>`'s and `HashSet<T, S>`'s basic methods.][58370] Most notably you no longer require the `Hash` trait to create an iterator. - [The `Ord` trait bounds have been removed on some of `BinaryHeap<T>`'s basic methods.][58421] Most notably you no longer require the `Ord` trait to create an iterator. - [The methods `overflowing_neg` and `wrapping_neg` are now `const` functions for all numeric types.][58044] - [Indexing a `str` is now generic over all types that implement `SliceIndex<str>`.][57604] - [`str::trim`, `str::trim_matches`, `str::trim_{start, end}`, and `str::trim_{start, end}_matches` are now `#[must_use]`][57106] and will produce a warning if their returning type is unused. - [The methods `checked_pow`, `saturating_pow`, `wrapping_pow`, and `overflowing_pow` are now available for all numeric types.][57873] These are equivalvent to methods such as `wrapping_add` for the `pow` operation. Stabilized APIs --------------- #### std & core * [`Any::type_id`] * [`Error::type_id`] * [`atomic::AtomicI16`] * [`atomic::AtomicI32`] * [`atomic::AtomicI64`] * [`atomic::AtomicI8`] * [`atomic::AtomicU16`] * [`atomic::AtomicU32`] * [`atomic::AtomicU64`] * [`atomic::AtomicU8`] * [`convert::Infallible`] * [`convert::TryFrom`] * [`convert::TryInto`] * [`iter::from_fn`] * [`iter::successors`] * [`num::NonZeroI128`] * [`num::NonZeroI16`] * [`num::NonZeroI32`] * [`num::NonZeroI64`] * [`num::NonZeroI8`] * [`num::NonZeroIsize`] * [`slice::sort_by_cached_key`] * [`str::escape_debug`] * [`str::escape_default`] * [`str::escape_unicode`] * [`str::split_ascii_whitespace`] #### std * [`Instant::checked_add`] * [`Instant::checked_sub`] * [`SystemTime::checked_add`] * [`SystemTime::checked_sub`] Cargo ----- - [You can now use alternative registries to crates.io.][cargo/6654] Misc ---- - [You can now use the `?` operator in your documentation tests without manually adding `fn main() -> Result<(), _> {}`.][56470] Compatibility Notes ------------------- - [`Command::before_exec` is now deprecated in favor of the unsafe method `Command::pre_exec`.][58059] - [Use of `ATOMIC_{BOOL, ISIZE, USIZE}_INIT` is now deprecated.][57425] As you can now use `const` functions in `static` variables. [58370]: rust-lang/rust#58370 [58406]: rust-lang/rust#58406 [58421]: rust-lang/rust#58421 [58166]: rust-lang/rust#58166 [58044]: rust-lang/rust#58044 [58057]: rust-lang/rust#58057 [58059]: rust-lang/rust#58059 [57809]: rust-lang/rust#57809 [57873]: rust-lang/rust#57873 [57604]: rust-lang/rust#57604 [57367]: rust-lang/rust#57367 [57407]: rust-lang/rust#57407 [57425]: rust-lang/rust#57425 [57106]: rust-lang/rust#57106 [56470]: rust-lang/rust#56470 [cargo/6654]: rust-lang/cargo#6654 [`Any::type_id`]: https://doc.rust-lang.org/std/any/trait.Any.html#tymethod.type_id [`Error::type_id`]: https://doc.rust-lang.org/std/error/trait.Error.html#tymethod.type_id [`atomic::AtomicI16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI16.html [`atomic::AtomicI32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI32.html [`atomic::AtomicI64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI64.html [`atomic::AtomicI8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI8.html [`atomic::AtomicU16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU16.html [`atomic::AtomicU32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU32.html [`atomic::AtomicU64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU64.html [`atomic::AtomicU8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU8.html [`convert::Infallible`]: https://doc.rust-lang.org/std/convert/enum.Infallible.html [`convert::TryFrom`]: https://doc.rust-lang.org/std/convert/trait.TryFrom.html [`convert::TryInto`]: https://doc.rust-lang.org/std/convert/trait.TryInto.html [`iter::from_fn`]: https://doc.rust-lang.org/std/iter/fn.from_fn.html [`iter::successors`]: https://doc.rust-lang.org/std/iter/fn.successors.html [`num::NonZeroI128`]: https://doc.rust-lang.org/std/num/struct.NonZeroI128.html [`num::NonZeroI16`]: https://doc.rust-lang.org/std/num/struct.NonZeroI16.html [`num::NonZeroI32`]: https://doc.rust-lang.org/std/num/struct.NonZeroI32.html [`num::NonZeroI64`]: https://doc.rust-lang.org/std/num/struct.NonZeroI64.html [`num::NonZeroI8`]: https://doc.rust-lang.org/std/num/struct.NonZeroI8.html [`num::NonZeroIsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroIsize.html [`slice::sort_by_cached_key`]: https://doc.rust-lang.org/std/slice/fn.sort_by_cached_key [`str::escape_debug`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug [`str::escape_default`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_default [`str::escape_unicode`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_unicode [`str::split_ascii_whitespace`]: https://doc.rust-lang.org/std/primitive.str.html#method.split_ascii_whitespace [`Instant::checked_add`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_add [`Instant::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_sub [`SystemTime::checked_add`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_add [`SystemTime::checked_sub`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_sub

deprecate before_exec in favor of unsafe pre_exec

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rust-highfive assigned withoutboats Feb 1, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 1, 2019

RalfJung added 2 commits February 1, 2019 19:57

also replace before_exec by pre_exec on redox

d48433d

update test

b1709d2

alexcrichton added the T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. label Feb 1, 2019

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 1, 2019

rust-highfive assigned alexcrichton and unassigned withoutboats Feb 1, 2019

RalfJung added 3 commits February 2, 2019 11:00

deprecate things a bit slower

cbbf8a7

pre_exec: expand docs

6c67a76

rustfmt the test

59da97d

alexcrichton reviewed Feb 2, 2019

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RalfJung added 2 commits February 3, 2019 11:16

more formatting

33ee99b

POSIX requires async signal safety for fork in signal handlers, not i…

e023403

…n general

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Centril mentioned this pull request Feb 20, 2019

Rollup of 12 pull requests #58594

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Centril mentioned this pull request Feb 22, 2019

Rollup of 18 pull requests #58637

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Centril mentioned this pull request Feb 22, 2019

Rollup of 17 pull requests #58644

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bors merged commit e023403 into rust-lang:master Feb 23, 2019

jorickert mentioned this pull request Apr 23, 2019

mark fork as unsafe nix-rust/nix#1047

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std::process::Command doesn't follow Unix signal safety in forked child #64718

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deprecate before_exec in favor of unsafe pre_exec #58059

deprecate before_exec in favor of unsafe pre_exec #58059

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deprecate before_exec in favor of unsafe pre_exec #58059

deprecate before_exec in favor of unsafe pre_exec #58059

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