Disable Ctrl-C handling on WASM

[bjorn3]

WASM fundamentally doesn't support signals. If WASI ever gets support for notifying the guest process of a Ctrl-C that happened, this would have to be done through the guest process polling for the signal, which will require thread support in WASI too to be compatible with the api provided by the ctrlc crate.

[rustbot]

r? @lcnr

rustbot has assigned @lcnr.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[rustbot]

The list of allowed third-party dependencies may have been modified! You must ensure that any new dependencies have compatible licenses before merging.

cc @davidtwco, @wesleywiser

[lcnr]

this seems reasonable to me, I don't know much about wasm though 🤷 cc @alexcrichton maybe? What's the impact of simply using ctrlc in wasm? do you get compilation failure/linker errors or is it simply a noop?

r=me after CI

[bjorn3]

CI failure is because of a tidy bug. It checks if a target dependent dependency applies to wasm and if so ignores it. This check however also triggers if it doesn't just apply to wasm but also to other targets. So for example cfg(not(windows)) would also be ignored as wasm is matched by cfg(not(windows)). Or in this case cfg(not(target_family = "wasm"))] is considered to be matched by wasm as target_family = "wasm" is not explicitly set in the check. I've pushed a commit to remove the filtering entirely. It only filtered out two deps anyway. At least one of which is incorrect and I think the other one is also incorrect.

[bjorn3]

What's the impact of simply using ctrlc in wasm? do you get compilation failure/linker errors or is it simply a noop?

I got a compilation failure when compiling the ctrlc crate.

The errors in question

error[E0432]: unresolved import `platform::Signal`
  --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/lib.rs:53:9
   |
53 | pub use platform::Signal;
   |         ^^^^^^^^^^^^^^^^ no `Signal` in `platform`

error[E0412]: cannot find type `Error` in module `platform`
  --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/error.rs:25:21
   |
25 | impl From<platform::Error> for Error {
   |                     ^^^^^ not found in `platform`
   |
help: consider importing one of these items
   |
1  + use core::error::Error;
   |
1  + use core::fmt::Error;
   |
1  + use crate::Error;
   |
1  + use crate::error::fmt::Error;
   |
     and 3 other candidates
help: if you import `Error`, refer to it directly
   |
25 - impl From<platform::Error> for Error {
25 + impl From<Error> for Error {
   |

error[E0412]: cannot find type `Error` in module `platform`
  --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/error.rs:26:26
   |
26 |     fn from(e: platform::Error) -> Error {
   |                          ^^^^^ not found in `platform`
   |
help: consider importing one of these items
   |
1  + use core::error::Error;
   |
1  + use core::fmt::Error;
   |
1  + use crate::Error;
   |
1  + use crate::error::fmt::Error;
   |
     and 3 other candidates
help: if you import `Error`, refer to it directly
   |
26 -     fn from(e: platform::Error) -> Error {
26 +     fn from(e: Error) -> Error {
   |

error[E0433]: failed to resolve: could not find `Error` in `platform`
  --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/error.rs:28:27
   |
28 |         if e == platform::Error::EEXIST {
   |                           ^^^^^ could not find `Error` in `platform`
   |
help: consider importing one of these items
   |
1  + use core::error::Error;
   |
1  + use core::fmt::Error;
   |
1  + use crate::Error;
   |
1  + use crate::error::fmt::Error;
   |
     and 3 other candidates
help: if you import `Error`, refer to it directly
   |
28 -         if e == platform::Error::EEXIST {
28 +         if e == Error::EEXIST {
   |

error[E0412]: cannot find type `Signal` in module `platform`
  --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/signal.rs:22:21
   |
22 |     Other(platform::Signal),
   |                     ^^^^^^ not found in `platform`

error[E0425]: cannot find function `init_os_handler` in module `platform`
   --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/lib.rs:134:25
    |
134 |         match platform::init_os_handler(overwrite) {
    |                         ^^^^^^^^^^^^^^^ not found in `platform`

error[E0425]: cannot find function `block_ctrl_c` in module `platform`
   --> /home/gh-bjorn3/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ctrlc-3.4.4/src/lib.rs:146:27
    |
146 |                 platform::block_ctrl_c().expect("Critical system error while waiting for Ctrl-C");
    |                           ^^^^^^^^^^^^ not found in `platform`

Some errors have detailed explanations: E0412, E0425, E0432, E0433.
For more information about an error, try `rustc --explain E0412`.
error: could not compile `ctrlc` (lib) due to 7 previous errors

[Noratrieb]

😈

[Noratrieb]

r=me

[bjorn3]

@bors r=Nilstrieb,lcnr

[bors]

📌 Commit 8b0b88a has been approved by Nilstrieb,lcnr

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8b0b88a with merge 72fe8a0...

[klensy]

cargo-platform became dead dep?

[alexcrichton]

Looks good to me as well 👍

[bjorn3]

Yes, the cargo-platform dependency can be removed. I've opened #123796 for this as this PR is already being tested by bors.

[bors]

☀️ Test successful - checks-actions
Approved by: Nilstrieb,lcnr
Pushing 72fe8a0 to master...

[rust-timer]

Finished benchmarking commit (72fe8a0): 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)	3.5%	[2.5%, 4.7%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.5%	[2.5%, 4.7%]	3

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)	6.3%	[2.4%, 8.9%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 676.108s -> 675.554s (-0.08%)
Artifact size: 316.01 MiB -> 316.02 MiB (0.00%)