signal-hook-tokio Windows build broken?

[davepacheco]

I created a crate that's basically empty and depends on signal-hook and signal-hook-tokio:
https://github.com/davepacheco/signal-hook-windows-test/blob/main/Cargo.toml

I have GitHub Actions configured to build this on Ubuntu, Windows, and MacOS. The Ubuntu one works, but the Windows one failed. (The MacOS one was aborted because of the Windows failure.) I've only tested this once here, but I see the same behavior in a bigger crate that uses these crates.

The error is here:

   Compiling signal-hook-tokio v0.3.0
     Running `rustc --crate-name signal_hook_tokio --edition=2018 C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg "feature=\"futures-core-0_3\"" --cfg "feature=\"futures-v0_3\"" -C metadata=3c6a7814b531fa0a -C extra-filename=-3c6a7814b531fa0a --out-dir D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps -L dependency=D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps --extern futures_core_0_3=D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps\libfutures_core-a1626673b76c3bb9.rmeta --extern libc=D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps\liblibc-aeda11fed0a8c75b.rmeta --extern signal_hook=D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps\libsignal_hook-ac6b3a1d0c81f434.rmeta --extern tokio=D:\a\signal-hook-windows-test\signal-hook-windows-test\target\debug\deps\libtokio-a1fd3de27efaed30.rmeta --cap-lints allow`
error[E0433]: failed to resolve: could not find `iterator` in `signal_hook`
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:81:22
   |
81 | pub use signal_hook::iterator::backend::Handle;
   |                      ^^^^^^^^ could not find `iterator` in `signal_hook`

error[E0433]: failed to resolve: could not find `iterator` in `signal_hook`
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:82:18
   |
82 | use signal_hook::iterator::backend::{OwningSignalIterator, PollResult, SignalDelivery};
   |                  ^^^^^^^^ could not find `iterator` in `signal_hook`

error[E0433]: failed to resolve: could not find `iterator` in `signal_hook`
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:83:18
   |
83 | use signal_hook::iterator::exfiltrator::{Exfiltrator, SignalOnly};
   |                  ^^^^^^^^ could not find `iterator` in `signal_hook`

error[E0432]: unresolved import `tokio::net::UnixStream`
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:79:5
   |
79 | use tokio::net::UnixStream;
   |     ^^^^^^^^^^^^^^^^^^^^^^ no `UnixStream` in `net`

error[E0433]: failed to resolve: use of undeclared type `SignalDelivery`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:115:21
    |
115 |         let inner = SignalDelivery::with_pipe(read, write, exfiltrator, signals)?;
    |                     ^^^^^^^^^^^^^^ use of undeclared type `SignalDelivery`

error[E0433]: failed to resolve: use of undeclared type `OwningSignalIterator`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:116:17
    |
116 |         Ok(Self(OwningSignalIterator::new(inner)))
    |                 ^^^^^^^^^^^^^^^^^^^^ use of undeclared type `OwningSignalIterator`

error[E0433]: failed to resolve: use of undeclared type `PollResult`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:153:13
    |
153 |             PollResult::Signal(sig) => Poll::Ready(Some(sig)),
    |             ^^^^^^^^^^ use of undeclared type `PollResult`

error[E0433]: failed to resolve: use of undeclared type `PollResult`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:154:13
    |
154 |             PollResult::Closed => Poll::Ready(None),
    |             ^^^^^^^^^^ use of undeclared type `PollResult`

error[E0433]: failed to resolve: use of undeclared type `PollResult`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:155:13
    |
155 |             PollResult::Pending => Poll::Pending,
    |             ^^^^^^^^^^ use of undeclared type `PollResult`

error[E0433]: failed to resolve: use of undeclared type `PollResult`
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:156:13
    |
156 |             PollResult::Err(error) => panic!("Unexpected error: {}", error),
    |             ^^^^^^^^^^ use of undeclared type `PollResult`

error[E0405]: cannot find trait `Exfiltrator` in this scope
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:92:27
   |
92 | pub struct SignalsInfo<E: Exfiltrator = SignalOnly>(OwningSignalIterator<UnixStream, E>);
   |                           ^^^^^^^^^^^ not found in this scope

error[E0412]: cannot find type `SignalOnly` in this scope
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:92:41
   |
92 | pub struct SignalsInfo<E: Exfiltrator = SignalOnly>(OwningSignalIterator<UnixStream, E>);
   |                                         ^^^^^^^^^^ not found in this scope

error[E0412]: cannot find type `OwningSignalIterator` in this scope
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:92:53
   |
92 | pub struct SignalsInfo<E: Exfiltrator = SignalOnly>(OwningSignalIterator<UnixStream, E>);
   |                                                     ^^^^^^^^^^^^^^^^^^^^ not found in this scope

error[E0405]: cannot find trait `Exfiltrator` in this scope
  --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:94:9
   |
94 | impl<E: Exfiltrator> SignalsInfo<E> {
   |         ^^^^^^^^^^^ not found in this scope

error[E0412]: cannot find type `Handle` in this scope
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:123:29
    |
123 |     pub fn handle(&self) -> Handle {
    |                             ^^^^^^ not found in this scope

error[E0412]: cannot find type `SignalOnly` in this scope
   --> C:\Users\runneradmin\.cargo\registry\src\github.com-1ecc6299db9ec823\signal-hook-tokio-0.3.0\src\lib.rs:132:32
    |
132 | pub type Signals = SignalsInfo<SignalOnly>;
    |                 -              ^^^^^^^^^^ not found in this scope
    |                 |
    |                 help: you might be missing a type parameter: `<SignalOnly>`

error: aborting due to 16 previous errors

[vorner]

Windows is kind of a secondary platform, since its support of signals is very limited. Parts of the crate are not available there as a result. You can turn these parts off by default-features = false and picking only the things you need.

You're right that it probably should build with the defaults and just have them unavailable there. I'll get around to fixing that eventually, but probably not right now. I'd suggest you use the workaround above in the meantime, but if you want to get involved and fix it, I'll be happy for a PR.

Thanks for reporting it.

[davepacheco]

No problem. I understand it's best-effort. My use case is very simple so I wound up using the ctrlc crate for now.

[vorner]

I'm looking into it right now. The signal-hook with default features builds OK on windows (well, with some warnings about unused imports, but 🤷). But the signal-hook-tokio depends on the iterator feature and that one isn't ported to windows, so signal-hook-tokio is incompatible with windows.

I admit the error should be a bit better though, but I don't see a good way how to do it :-|.

[pickfire]

https://github.com/helix-editor/helix/pull/464/checks?check_run_id=3093468552

We also get that on iterator, I think a workaround is remove signal-hook-tokio for windows.

[mediocregopher]

Tokio has a cross-platform ctrl-c signal handler, for those looking for a basic graceful shutdown feature: https://docs.rs/tokio/1.34.0/tokio/signal/fn.ctrl_c.html