d70595b667
# Objective - Fixes #6370 - Closes #6581 ## Solution - Added the following lints to the workspace: - `std_instead_of_core` - `std_instead_of_alloc` - `alloc_instead_of_core` - Used `cargo +nightly fmt` with [item level use formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A) to split all `use` statements into single items. - Used `cargo clippy --workspace --all-targets --all-features --fix --allow-dirty` to _attempt_ to resolve the new linting issues, and intervened where the lint was unable to resolve the issue automatically (usually due to needing an `extern crate alloc;` statement in a crate root). - Manually removed certain uses of `std` where negative feature gating prevented `--all-features` from finding the offending uses. - Used `cargo +nightly fmt` with [crate level use formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A) to re-merge all `use` statements matching Bevy's previous styling. - Manually fixed cases where the `fmt` tool could not re-merge `use` statements due to conditional compilation attributes. ## Testing - Ran CI locally ## Migration Guide The MSRV is now 1.81. Please update to this version or higher. ## Notes - This is a _massive_ change to try and push through, which is why I've outlined the semi-automatic steps I used to create this PR, in case this fails and someone else tries again in the future. - Making this change has no impact on user code, but does mean Bevy contributors will be warned to use `core` and `alloc` instead of `std` where possible. - This lint is a critical first step towards investigating `no_std` options for Bevy. --------- Co-authored-by: François Mockers <francois.mockers@vleue.com>
83 lines
3.1 KiB
Rust
83 lines
3.1 KiB
Rust
use core::{
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any::Any,
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future::{Future, IntoFuture},
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panic::{AssertUnwindSafe, UnwindSafe},
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pin::Pin,
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task::Poll,
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};
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use futures_channel::oneshot;
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/// Wraps an asynchronous task, a spawned future.
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///
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/// Tasks are also futures themselves and yield the output of the spawned future.
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#[derive(Debug)]
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pub struct Task<T>(oneshot::Receiver<Result<T, Panic>>);
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impl<T: 'static> Task<T> {
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pub(crate) fn wrap_future(future: impl Future<Output = T> + 'static) -> Self {
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let (sender, receiver) = oneshot::channel();
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wasm_bindgen_futures::spawn_local(async move {
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// Catch any panics that occur when polling the future so they can
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// be propagated back to the task handle.
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let value = CatchUnwind(AssertUnwindSafe(future)).await;
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let _ = sender.send(value);
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});
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Self(receiver.into_future())
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}
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/// When building for Wasm, this method has no effect.
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/// This is only included for feature parity with other platforms.
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pub fn detach(self) {}
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/// Requests a task to be cancelled and returns a future that suspends until it completes.
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/// Returns the output of the future if it has already completed.
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///
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/// # Implementation
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///
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/// When building for Wasm, it is not possible to cancel tasks, which means this is the same
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/// as just awaiting the task. This method is only included for feature parity with other platforms.
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pub async fn cancel(self) -> Option<T> {
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match self.0.await {
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Ok(Ok(value)) => Some(value),
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Err(_) => None,
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Ok(Err(panic)) => {
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// drop this to prevent the panic payload from resuming the panic on drop.
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// this also leaks the box but I'm not sure how to avoid that
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core::mem::forget(panic);
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None
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}
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}
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}
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}
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impl<T> Future for Task<T> {
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type Output = T;
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fn poll(
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mut self: core::pin::Pin<&mut Self>,
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cx: &mut core::task::Context<'_>,
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) -> std::task::Poll<Self::Output> {
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match Pin::new(&mut self.0).poll(cx) {
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Poll::Ready(Ok(Ok(value))) => Poll::Ready(value),
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// NOTE: Propagating the panic here sorta has parity with the async_executor behavior.
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// For those tasks, polling them after a panic returns a `None` which gets `unwrap`ed, so
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// using `resume_unwind` here is essentially keeping the same behavior while adding more information.
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Poll::Ready(Ok(Err(panic))) => std::panic::resume_unwind(panic),
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Poll::Ready(Err(_)) => panic!("Polled a task after it was cancelled"),
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Poll::Pending => Poll::Pending,
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}
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}
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}
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type Panic = Box<dyn Any + Send + 'static>;
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#[pin_project::pin_project]
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struct CatchUnwind<F: UnwindSafe>(#[pin] F);
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impl<F: Future + UnwindSafe> Future for CatchUnwind<F> {
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type Output = Result<F::Output, Panic>;
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fn poll(self: core::pin::Pin<&mut Self>, cx: &mut core::task::Context) -> Poll<Self::Output> {
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std::panic::catch_unwind(AssertUnwindSafe(|| self.project().0.poll(cx)))?.map(Ok)
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}
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}
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