Replace `-Zon-broken-pipe=...` with Externally Implementable Item `#[std::io::on_broken_pipe]` by Enselic · Pull Request #150591 · rust-lang/rust

Enselic · 2026-01-02T11:57:03Z

The code in this PR also acts as a regression test for the fix to #150588 which I will split out in a separate PR.

TODO

Fix Hundreds of missing stability attribute errors with trivial Externally Implementable Item (eii) function in library/std #150514 first in a separate PR (see compiler: Make Externally Implementable Items (eii) in std build #150592)
Too many to enumerate...

Tracking Issues:

src/tools/miri/src/shims/foreign_items.rs

rustc book: fix grammar It was added in ddee45e ([here](https://github.com/rust-lang/rust/pull/97802/changes#diff-85dc642a7bdad363a9e37d2491230280fcd977391ba7a242bda2da9ddb55f654) to be specific) when SIGPIPE was controlled with an attribute on `fn main()` which meant it could also be combined with `#[rustc_main]`: #[unix_sigpipe = "sig_dfl"] #[rustc_main] fn rustc_main() { The test stopped being needed in cde0cde when `#[unix_sigpipe = "..."]` was replaced by `-Zon-broken-pipe=...`. And it will not be needed when `-Zon-broken-pipe=...` is replaced by an Externally Implementable Item (see rust-lang#150591). Let's remove this test. Tracking issue: - rust-lang#150588

tests/ui/runtime/on-broken-pipe/with-rustc_main.rs: Not needed so remove It was added in ddee45e ([here](https://github.com/rust-lang/rust/pull/97802/changes#diff-85dc642a7bdad363a9e37d2491230280fcd977391ba7a242bda2da9ddb55f654) to be specific) when SIGPIPE was controlled with an attribute on `fn main()` which meant it could also be combined with `#[rustc_main]`: #[unix_sigpipe = "sig_dfl"] #[rustc_main] fn rustc_main() { The test stopped being needed in cde0cde when `#[unix_sigpipe = "..."]` was replaced by `-Zon-broken-pipe=...`. And it will not be needed when `-Zon-broken-pipe=...` is replaced by an Externally Implementable Item (see rust-lang#150591). Let's remove this test. Tracking issue: - rust-lang#150588

Fix `alloc_error_handler` signature mismatch It was added in ddee45e ([here](https://github.com/rust-lang/rust/pull/97802/changes#diff-85dc642a7bdad363a9e37d2491230280fcd977391ba7a242bda2da9ddb55f654) to be specific) when SIGPIPE was controlled with an attribute on `fn main()` which meant it could also be combined with `#[rustc_main]`: #[unix_sigpipe = "sig_dfl"] #[rustc_main] fn rustc_main() { The test stopped being needed in cde0cde when `#[unix_sigpipe = "..."]` was replaced by `-Zon-broken-pipe=...`. And it will not be needed when `-Zon-broken-pipe=...` is replaced by an Externally Implementable Item (see rust-lang#150591). Let's remove this test. Tracking issue: - rust-lang#150588

Rollup merge of #150757 - rm-unneded-test, r=bjorn3 Fix `alloc_error_handler` signature mismatch It was added in ddee45e ([here](https://github.com/rust-lang/rust/pull/97802/changes#diff-85dc642a7bdad363a9e37d2491230280fcd977391ba7a242bda2da9ddb55f654) to be specific) when SIGPIPE was controlled with an attribute on `fn main()` which meant it could also be combined with `#[rustc_main]`: #[unix_sigpipe = "sig_dfl"] #[rustc_main] fn rustc_main() { The test stopped being needed in cde0cde when `#[unix_sigpipe = "..."]` was replaced by `-Zon-broken-pipe=...`. And it will not be needed when `-Zon-broken-pipe=...` is replaced by an Externally Implementable Item (see #150591). Let's remove this test. Tracking issue: - #150588

rust-bors · 2026-01-10T05:19:19Z

☔ The latest upstream changes (presumably #150900) made this pull request unmergeable. Please resolve the merge conflicts.

@jdonszelmann

compiler: Forward attributes to eii-expanded macros Since rust-lang#150592 is quite complicated to reason about I figured it would be good to split it up in smaller pieces that are easier to digest. Here is the attribute fix in isolation. ## The Problem With this eii in **library/std/src/io/mod.rs**: ```rs /// Foo #[eii(on_broken_pipe)] #[unstable(feature = "on_broken_pipe", issue = "150588")] pub fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } ``` you currently get this compilation error: ``` error: attribute macro has missing stability attribute --> library/std/src/io/mod.rs:2269:1 | 2269 | #[eii(on_broken_pipe)] | ^^^^^^^^^^^^^^^^^^^^-- | | | in this attribute macro expansion | ::: library/core/src/macros/mod.rs:1899:5 | 1899 | pub macro eii($item:item) { | ------------- in this expansion of `#[eii]` ``` because with ` MAGIC_EXTRA_RUSTFLAGS=-Zunpretty=expanded ./x build library/std` we can see that a pub item in the expanded code is indeed missing that attribute: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` ## The Solution With the fix, that error goes away because we get this expanded code instead: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` Note that we also need to forward the docs, otherwise get get (fatal) warnings like these: ``` warning: missing documentation for an attribute macro --> library/std/src/io/mod.rs:2269:1 ``` r? @jdonszelmann Tracking issues: - rust-lang#125418 - rust-lang#150588 ### What about a test? rust-lang#150591 will prevent regressions once it lands since it does not build without this fix. I think it is overkill to add a temporary eii to std before that.

@jdonszelmann

compiler: Forward attributes to eii-expanded macros Since rust-lang#150592 is quite complicated to reason about I figured it would be good to split it up in smaller pieces that are easier to digest. Here is the attribute fix in isolation. ## The Problem With this eii in **library/std/src/io/mod.rs**: ```rs /// Foo #[eii(on_broken_pipe)] #[unstable(feature = "on_broken_pipe", issue = "150588")] pub fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } ``` you currently get this compilation error: ``` error: attribute macro has missing stability attribute --> library/std/src/io/mod.rs:2269:1 | 2269 | #[eii(on_broken_pipe)] | ^^^^^^^^^^^^^^^^^^^^-- | | | in this attribute macro expansion | ::: library/core/src/macros/mod.rs:1899:5 | 1899 | pub macro eii($item:item) { | ------------- in this expansion of `#[eii]` ``` because with ` MAGIC_EXTRA_RUSTFLAGS=-Zunpretty=expanded ./x build library/std` we can see that a pub item in the expanded code is indeed missing that attribute: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` ## The Solution With the fix, that error goes away because we get this expanded code instead: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` Note that we also need to forward the docs, otherwise get get (fatal) warnings like these: ``` warning: missing documentation for an attribute macro --> library/std/src/io/mod.rs:2269:1 ``` r? @jdonszelmann Tracking issues: - rust-lang#125418 - rust-lang#150588 ### What about a test? rust-lang#150591 will prevent regressions once it lands since it does not build without this fix. I think it is overkill to add a temporary eii to std before that.

@jdonszelmann

Rollup merge of #150913 - eii-macro-attrs, r=jdonszelmann compiler: Forward attributes to eii-expanded macros Since #150592 is quite complicated to reason about I figured it would be good to split it up in smaller pieces that are easier to digest. Here is the attribute fix in isolation. ## The Problem With this eii in **library/std/src/io/mod.rs**: ```rs /// Foo #[eii(on_broken_pipe)] #[unstable(feature = "on_broken_pipe", issue = "150588")] pub fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } ``` you currently get this compilation error: ``` error: attribute macro has missing stability attribute --> library/std/src/io/mod.rs:2269:1 | 2269 | #[eii(on_broken_pipe)] | ^^^^^^^^^^^^^^^^^^^^-- | | | in this attribute macro expansion | ::: library/core/src/macros/mod.rs:1899:5 | 1899 | pub macro eii($item:item) { | ------------- in this expansion of `#[eii]` ``` because with ` MAGIC_EXTRA_RUSTFLAGS=-Zunpretty=expanded ./x build library/std` we can see that a pub item in the expanded code is indeed missing that attribute: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` ## The Solution With the fix, that error goes away because we get this expanded code instead: ```rs const _: () = { #[on_broken_pipe] fn on_broken_pipe() -> OnBrokenPipe { OnBrokenPipe::BackwardsCompatible } }; unsafe extern "Rust" { /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_eii_extern_item] pub safe fn on_broken_pipe() -> OnBrokenPipe; } /// Foo #[unstable(feature = "on_broken_pipe", issue = "150588")] #[rustc_builtin_macro(eii_shared_macro)] #[eii_extern_target(on_broken_pipe)] pub macro on_broken_pipe { () => {} } ``` Note that we also need to forward the docs, otherwise get get (fatal) warnings like these: ``` warning: missing documentation for an attribute macro --> library/std/src/io/mod.rs:2269:1 ``` r? @jdonszelmann Tracking issues: - #125418 - #150588 ### What about a test? #150591 will prevent regressions once it lands since it does not build without this fix. I think it is overkill to add a temporary eii to std before that.

…mic-v2, r=jdonszelmann compiletest: Don't assume `aux-crate` becomes a `*.so` with `no-prefer-dynamic` Since it does not make sense to do so. If someone prefers no dynamic stuff, the last thing they want to look for is an .so file. Also add a regression test. Without the fix, the test fails with: error: test compilation failed although it shouldn't! --- stderr ------------------------------- error: extern location for no_prefer_dynamic_lib does not exist: .../auxiliary/libno_prefer_dynamic_lib.so --> .../no-prefer-dynamic-means-no-so.rs:9:5 | LL | no_prefer_dynamic_lib::return_42(); | ^^^^^^^^^^^^^^^^^^^^^ ### Needed by: - rust-lang#150591 because of rust-lang#151271. But IMHO this PR makes sense on its own. ### Must wait for: - [x] rust-lang#151695

Rollup merge of #151691 - Enselic:dylib-only-for-prefer-dynamic-v2, r=jdonszelmann compiletest: Don't assume `aux-crate` becomes a `*.so` with `no-prefer-dynamic` Since it does not make sense to do so. If someone prefers no dynamic stuff, the last thing they want to look for is an .so file. Also add a regression test. Without the fix, the test fails with: error: test compilation failed although it shouldn't! --- stderr ------------------------------- error: extern location for no_prefer_dynamic_lib does not exist: .../auxiliary/libno_prefer_dynamic_lib.so --> .../no-prefer-dynamic-means-no-so.rs:9:5 | LL | no_prefer_dynamic_lib::return_42(); | ^^^^^^^^^^^^^^^^^^^^^ ### Needed by: - #150591 because of #151271. But IMHO this PR makes sense on its own. ### Must wait for: - [x] #151695

…=jdonszelmann compiletest: Don't assume `aux-crate` becomes a `*.so` with `no-prefer-dynamic` Since it does not make sense to do so. If someone prefers no dynamic stuff, the last thing they want to look for is an .so file. Also add a regression test. Without the fix, the test fails with: error: test compilation failed although it shouldn't! --- stderr ------------------------------- error: extern location for no_prefer_dynamic_lib does not exist: .../auxiliary/libno_prefer_dynamic_lib.so --> .../no-prefer-dynamic-means-no-so.rs:9:5 | LL | no_prefer_dynamic_lib::return_42(); | ^^^^^^^^^^^^^^^^^^^^^ ### Needed by: - rust-lang/rust#150591 because of rust-lang/rust#151271. But IMHO this PR makes sense on its own. ### Must wait for: - [x] rust-lang/rust#151695

…, r=ChrisDenton library/std: Rename `ON_BROKEN_PIPE_FLAG_USED` to `ON_BROKEN_PIPE_USED` This commit is a pure internal rename and does not change any functionality. The `FLAG_` part of `ON_BROKEN_PIPE_FLAG_USED` comes from that the compiler flag `-Zon-broken-pipe=...` is used to enable the feature. Remove the `FLAG_` part so the name works both for the current compiler flag `-Zon-broken-pipe=...` and for the upcoming [Externally Implementable Item `#[std::io::on_broken_pipe]`](rust-lang#150591) PR. This makes the diff of that PR smaller. The local variable name `sigpipe_attr_specified` comes from way back when the feature was controlled with an `fn main()` attribute called `#[unix_sigpipe = "..."]`. Rename that too.

Rollup merge of #152133 - Enselic:on-broken-pipe-flag-rename, r=ChrisDenton library/std: Rename `ON_BROKEN_PIPE_FLAG_USED` to `ON_BROKEN_PIPE_USED` This commit is a pure internal rename and does not change any functionality. The `FLAG_` part of `ON_BROKEN_PIPE_FLAG_USED` comes from that the compiler flag `-Zon-broken-pipe=...` is used to enable the feature. Remove the `FLAG_` part so the name works both for the current compiler flag `-Zon-broken-pipe=...` and for the upcoming [Externally Implementable Item `#[std::io::on_broken_pipe]`](#150591) PR. This makes the diff of that PR smaller. The local variable name `sigpipe_attr_specified` comes from way back when the feature was controlled with an `fn main()` attribute called `#[unix_sigpipe = "..."]`. Rename that too.

…std::io::on_broken_pipe]`

Enselic changed the title ~~Add on broken pipe~~ Add initial #![feature(on_broken_pipe)] code Jan 2, 2026

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compiler: Make Externally Implementable Items (eii) in std build #150592

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Enselic force-pushed the add-on_broken_pipe branch 2 times, most recently from 5825fb6 to 7b52018 Compare January 5, 2026 21:46

Enselic changed the title ~~Add initial #![feature(on_broken_pipe)] code~~ Replace -Zon-broken-pipe=... with Externally Implementable Item #[std::io::on_broken_pipe() -> std::io::OnBrokenPipe Jan 5, 2026

Enselic changed the title ~~Replace -Zon-broken-pipe=... with Externally Implementable Item #[std::io::on_broken_pipe() -> std::io::OnBrokenPipe~~ Replace -Zon-broken-pipe=... with Externally Implementable Item #[std::io::on_broken_pipe] Jan 5, 2026

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RalfJung reviewed Jan 6, 2026

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src/tools/miri/src/shims/foreign_items.rs Outdated Show resolved Hide resolved

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Tracking Issue for Externally Implementable Item #[std::io::on_broken_pipe] #150588

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tests/ui/runtime/on-broken-pipe/with-rustc_main.rs: Not needed so remove #150747

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broken MIR in DefId(0:15 ~ nocore[d905]::{impl#0}::add) #92157

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compiler: Forward attributes to eii-expanded macros #150913

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compiletest: Don't look for Dylib if no-prefer-dynamic #151257

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compiletest: Don't assume aux-crate becomes a *.so with no-prefer-dynamic #151691

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rustbot added the A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. label Feb 3, 2026

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library/std: Rename ON_BROKEN_PIPE_FLAG_USED to ON_BROKEN_PIPE_USED #152133

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Replace -Zon-broken-pipe=... with Externally Implementable Item `#[…

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…std::io::on_broken_pipe]`

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Replace `-Zon-broken-pipe=...` with Externally Implementable Item `#[std::io::on_broken_pipe]`#150591

Replace `-Zon-broken-pipe=...` with Externally Implementable Item `#[std::io::on_broken_pipe]`#150591
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Enselic commented Jan 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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TODO

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Enselic commented Jan 2, 2026 •

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