Fix exit status / wait status on non-Unix cfg(unix) platforms

[ijackson]

Fixes #114593

Needs FCP due to behavioural changes (NB only on non-Unix #[cfg(unix)] platforms).

Also, I think this is likely to break in CI. I have not been yet able to compile the new bits of process_unsupported.rs, although I have compiled the new module. I'd like some help from people familiar with eg emscripten and fuchsia (which are going to be affected, I think).

[rustbot]

r? @Mark-Simulacrum

(rustbot has picked a reviewer for you, use r? to override)

[Mark-Simulacrum]

r? libs-api

[dtolnay]

@rust-lang/libs-api:
@rfcbot fcp merge

• Background reading: non-Unix cfg(unix) ExitStatus is broken #114593

This PR makes code like ExitStatus::from_raw(0).is_success() have sensible behavior on non-Unix platforms where cfg(unix) is true (ESP-IDF, Nintendo Switch, PlayStation Vita, ...) even when process spawning is unsupported by the platform.

[rfcbot]

Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), 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.

[rfcbot]

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

[rfcbot]

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

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[dtolnay]

Thank you!

[dtolnay]

@bors r+

[bors]

📌 Commit f625528 has been approved by dtolnay

It is now in the queue for this repository.

[bors]

⌛ Testing commit f625528 with merge 9857952...

[bors]

☀️ Test successful - checks-actions
Approved by: dtolnay
Pushing 9857952 to master...

[rust-timer]

Finished benchmarking commit (9857952): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	5.7%	[5.7%, 5.7%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.6%	[-3.6%, -3.6%]	1
All ❌✅ (primary)	5.7%	[5.7%, 5.7%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 628.687s -> 628.012s (-0.11%)
Artifact size: 271.30 MiB -> 271.32 MiB (0.01%)

[nikarh]

Hey, it looks like this PR breaks the compilation for armv7-sony-vita-newlibeabihf target, seems to be a module resolution problem.

error[E0583]: file not found for module `wait_status`
  --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/process/process_unsupported.rs:58:1
   |
58 | mod wait_status;
   | ^^^^^^^^^^^^^^^^
   |
   = help: to create the module `wait_status`, create file "/home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/process/wait_status.rs" or "/home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/process/wait_status/mod.rs"

error[E0432]: unresolved import `wait_status::ExitStatus`
  --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/process/process_unsupported.rs:59:9
   |
59 | pub use wait_status::ExitStatus;
   |         ^^^^^^^^^^^^^^^^^^^^^^^ no `ExitStatus` in `sys::unix::process::process_inner::wait_status`
   |
help: consider importing this struct instead
   |
59 | pub use crate::process::ExitStatus;
   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~

error[E0432]: unresolved import `crate::sys::process::ExitStatus`
  --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/process.rs:10:35
   |
10 | use crate::sys::process::{EnvKey, ExitStatus, Process, StdioPipes};
   |                                   ^^^^^^^^^^ no `ExitStatus` in `sys::unix::process`
   |
   = help: consider importing this struct instead:
           crate::process::ExitStatus

error[E0599]: no function or associated item named `from_inner` found for struct `ExitStatus` in the current scope
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:300:30
     |
300  |         process::ExitStatus::from_inner(From::from(raw))
     |                              ^^^^^^^^^^ function or associated item not found in `ExitStatus`
     |
    ::: /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/process.rs:1594:1
     |
1594 | pub struct ExitStatus(imp::ExitStatus);
     | --------------------- function or associated item `from_inner` not found for this struct
     |
     = help: items from traits can only be used if the trait is implemented and in scope
note: `FromInner` defines an item `from_inner`, perhaps you need to implement it
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:80:1
     |
80   | pub trait FromInner<Inner> {
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no method named `as_inner` found for reference `&ExitStatus` in the current scope
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:304:14
    |
304 |         self.as_inner().signal()
    |              ^^^^^^^^ method not found in `&ExitStatus`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
note: `AsInner` defines an item `as_inner`, perhaps you need to implement it
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:62:1
    |
62  | pub trait AsInner<Inner: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no method named `as_inner` found for reference `&ExitStatus` in the current scope
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:308:14
    |
308 |         self.as_inner().core_dumped()
    |              ^^^^^^^^ method not found in `&ExitStatus`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
note: `AsInner` defines an item `as_inner`, perhaps you need to implement it
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:62:1
    |
62  | pub trait AsInner<Inner: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no method named `as_inner` found for reference `&ExitStatus` in the current scope
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:312:14
    |
312 |         self.as_inner().stopped_signal()
    |              ^^^^^^^^ method not found in `&ExitStatus`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
note: `AsInner` defines an item `as_inner`, perhaps you need to implement it
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:62:1
    |
62  | pub trait AsInner<Inner: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no method named `as_inner` found for reference `&ExitStatus` in the current scope
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:316:14
    |
316 |         self.as_inner().continued()
    |              ^^^^^^^^ method not found in `&ExitStatus`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
note: `AsInner` defines an item `as_inner`, perhaps you need to implement it
   --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:62:1
    |
62  | pub trait AsInner<Inner: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no method named `as_inner` found for struct `ExitStatus` in the current scope
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/os/unix/process.rs:320:14
     |
320  |         self.as_inner().into_raw().into()
     |              ^^^^^^^^ method not found in `ExitStatus`
     |
    ::: /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/process.rs:1594:1
     |
1594 | pub struct ExitStatus(imp::ExitStatus);
     | --------------------- method `as_inner` not found for this struct
     |
     = help: items from traits can only be used if the trait is implemented and in scope
note: `AsInner` defines an item `as_inner`, perhaps you need to implement it
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:62:1
     |
62   | pub trait AsInner<Inner: ?Sized> {
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0599]: no function or associated item named `from_inner` found for struct `ExitStatus` in the current scope
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/process.rs:1601:21
     |
1594 | pub struct ExitStatus(imp::ExitStatus);
     | --------------------- function or associated item `from_inner` not found for this struct
...
1601 |         ExitStatus::from_inner(imp::ExitStatus::default())
     |                     ^^^^^^^^^^ function or associated item not found in `ExitStatus`
     |
     = help: items from traits can only be used if the trait is implemented and in scope
note: `FromInner` defines an item `from_inner`, perhaps you need to implement it
    --> /home/nikarh/.local/share/rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/mod.rs:80:1
     |
80   | pub trait FromInner<Inner> {
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^

Some errors have detailed explanations: E0432, E0583, E0599.
For more information about an error, try `rustc --explain E0432`.
error: could not compile `std` (lib) due to 10 previous errors
Error: cargo build failed