fix: [Local]SpawnExt should take &self as their base traits

Seems like an oversight in rust-lang#1950

Technically a

BREAKING CHANGE

futures-executor/src/local_pool.rs

@@ -2,12 +2,12 @@ use crate::enter;
 use futures_core::future::Future;
 use futures_core::stream::Stream;
 use futures_core::task::{Context, Poll};
-use futures_task::{FutureObj, LocalFutureObj, Spawn, LocalSpawn, SpawnError};
 use futures_task::{waker_ref, ArcWake};
+use futures_task::{FutureObj, LocalFutureObj, LocalSpawn, Spawn, SpawnError};
+use futures_util::pin_mut;
 use futures_util::stream::FuturesUnordered;
 use futures_util::stream::StreamExt;
-use futures_util::pin_mut;
-use std::cell::{RefCell};
+use std::cell::RefCell;
 use std::ops::{Deref, DerefMut};
 use std::rc::{Rc, Weak};
 use std::sync::Arc;
@@ -40,7 +40,7 @@ pub struct LocalSpawner {
 type Incoming = RefCell<Vec<LocalFutureObj<'static, ()>>>;
 
 pub(crate) struct ThreadNotify {
-    thread: Thread
+    thread: Thread,
 }
 
 thread_local! {
@@ -58,9 +58,10 @@ impl ArcWake for ThreadNotify {
 // Set up and run a basic single-threaded spawner loop, invoking `f` on each
 // turn.
 fn run_executor<T, F: FnMut(&mut Context<'_>) -> Poll<T>>(mut f: F) -> T {
-    let _enter = enter()
-        .expect("cannot execute `LocalPool` executor from within \
-                 another executor");
+    let _enter = enter().expect(
+        "cannot execute `LocalPool` executor from within \
+         another executor",
+    );
 
     CURRENT_THREAD_NOTIFY.with(|thread_notify| {
         let waker = waker_ref(thread_notify);
@@ -75,9 +76,10 @@ fn run_executor<T, F: FnMut(&mut Context<'_>) -> Poll<T>>(mut f: F) -> T {
 }
 
 fn poll_executor<T, F: FnMut(&mut Context<'_>) -> T>(mut f: F) -> T {
-    let _enter = enter()
-        .expect("cannot execute `LocalPool` executor from within \
-                 another executor");
+    let _enter = enter().expect(
+        "cannot execute `LocalPool` executor from within \
+         another executor",
+    );
 
     CURRENT_THREAD_NOTIFY.with(|thread_notify| {
         let waker = waker_ref(thread_notify);
@@ -98,7 +100,7 @@ impl LocalPool {
     /// Get a clonable handle to the pool as a [`Spawn`].
     pub fn spawner(&self) -> LocalSpawner {
         LocalSpawner {
-            incoming: Rc::downgrade(&self.incoming)
+            incoming: Rc::downgrade(&self.incoming),
         }
     }
 
@@ -164,7 +166,7 @@ impl LocalPool {
     /// use futures::future::{ready, pending};
     ///
     /// let mut pool = LocalPool::new();
-    /// let mut spawner = pool.spawner();
+    /// let spawner = pool.spawner();
     ///
     /// spawner.spawn_local(ready(())).unwrap();
     /// spawner.spawn_local(ready(())).unwrap();
@@ -212,7 +214,7 @@ impl LocalPool {
     /// use futures::future::{ready, pending};
     ///
     /// let mut pool = LocalPool::new();
-    /// let mut spawner = pool.spawner();
+    /// let spawner = pool.spawner();
     ///
     /// spawner.spawn_local(ready(())).unwrap();
     /// spawner.spawn_local(ready(())).unwrap();
@@ -229,7 +231,7 @@ impl LocalPool {
     /// of the pool's run or poll methods. While the function is running, all tasks
     /// in the pool will try to make progress.
     pub fn run_until_stalled(&mut self) {
-        poll_executor(|ctx| { 
+        poll_executor(|ctx| {
             let _ = self.poll_pool(ctx);
         });
     }
@@ -297,7 +299,9 @@ pub fn block_on_stream<S: Stream + Unpin>(stream: S) -> BlockingStream<S> {
 
 /// An iterator which blocks on values from a stream until they become available.
 #[derive(Debug)]
-pub struct BlockingStream<S: Stream + Unpin> { stream: S }
+pub struct BlockingStream<S: Stream + Unpin> {
+    stream: S,
+}
 
 impl<S: Stream + Unpin> Deref for BlockingStream<S> {
     type Target = S;
@@ -332,10 +336,7 @@ impl<S: Stream + Unpin> Iterator for BlockingStream<S> {
 }
 
 impl Spawn for LocalSpawner {
-    fn spawn_obj(
-        &self,
-        future: FutureObj<'static, ()>,
-    ) -> Result<(), SpawnError> {
+    fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
         if let Some(incoming) = self.incoming.upgrade() {
             incoming.borrow_mut().push(future.into());
             Ok(())
@@ -354,10 +355,7 @@ impl Spawn for LocalSpawner {
 }
 
 impl LocalSpawn for LocalSpawner {
-    fn spawn_local_obj(
-        &self,
-        future: LocalFutureObj<'static, ()>,
-    ) -> Result<(), SpawnError> {
+    fn spawn_local_obj(&self, future: LocalFutureObj<'static, ()>) -> Result<(), SpawnError> {
         if let Some(incoming) = self.incoming.upgrade() {
             incoming.borrow_mut().push(future);
             Ok(())

futures-task/src/spawn.rs

@@ -83,6 +83,16 @@ impl SpawnError {
     }
 }
 
+impl<Sp: ?Sized + Spawn> Spawn for &Sp {
+    fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
+        Sp::spawn_obj(self, future)
+    }
+
+    fn status(&self) -> Result<(), SpawnError> {
+        Sp::status(self)
+    }
+}
+
 impl<Sp: ?Sized + Spawn> Spawn for &mut Sp {
     fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
         Sp::spawn_obj(self, future)
@@ -103,6 +113,16 @@ impl<Sp: ?Sized + LocalSpawn> LocalSpawn for &Sp {
     }
 }
 
+impl<Sp: ?Sized + LocalSpawn> LocalSpawn for &mut Sp {
+    fn spawn_local_obj(&self, future: LocalFutureObj<'static, ()>) -> Result<(), SpawnError> {
+        Sp::spawn_local_obj(self, future)
+    }
+
+    fn status_local(&self) -> Result<(), SpawnError> {
+        Sp::status_local(self)
+    }
+}
+
 #[cfg(feature = "alloc")]
 mod if_alloc {
     use super::*;

futures-test/src/task/noop_spawner.rs

@@ -1,4 +1,4 @@
-use futures_task::{Spawn, SpawnError, FutureObj};
+use futures_task::{FutureObj, Spawn, SpawnError};
 
 /// An implementation of [`Spawn`](futures_task::Spawn) that
 /// discards spawned futures when used.
@@ -9,7 +9,7 @@ use futures_task::{Spawn, SpawnError, FutureObj};
 /// use futures::task::SpawnExt;
 /// use futures_test::task::NoopSpawner;
 ///
-/// let mut spawner = NoopSpawner::new();
+/// let spawner = NoopSpawner::new();
 /// spawner.spawn(async { }).unwrap();
 /// ```
 #[derive(Debug)]
@@ -25,10 +25,7 @@ impl NoopSpawner {
 }
 
 impl Spawn for NoopSpawner {
-    fn spawn_obj(
-        &self,
-        _future: FutureObj<'static, ()>,
-    ) -> Result<(), SpawnError> {
+    fn spawn_obj(&self, _future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
         Ok(())
     }
 }

futures-test/src/task/panic_spawner.rs

@@ -1,4 +1,4 @@
-use futures_task::{Spawn, SpawnError, FutureObj};
+use futures_task::{FutureObj, Spawn, SpawnError};
 
 /// An implementation of [`Spawn`](futures_task::Spawn) that panics
 /// when used.
@@ -9,7 +9,7 @@ use futures_task::{Spawn, SpawnError, FutureObj};
 /// use futures::task::SpawnExt;
 /// use futures_test::task::PanicSpawner;
 ///
-/// let mut spawn = PanicSpawner::new();
+/// let spawn = PanicSpawner::new();
 /// spawn.spawn(async { })?; // Will panic
 /// # Ok::<(), Box<dyn std::error::Error>>(())
 /// ```
@@ -26,10 +26,7 @@ impl PanicSpawner {
 }
 
 impl Spawn for PanicSpawner {
-    fn spawn_obj(
-        &self,
-        _future: FutureObj<'static, ()>,
-    ) -> Result<(), SpawnError> {
+    fn spawn_obj(&self, _future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
         panic!("should not spawn")
     }
 }

futures-test/src/task/record_spawner.rs

@@ -1,4 +1,4 @@
-use futures_task::{Spawn, SpawnError, FutureObj};
+use futures_task::{FutureObj, Spawn, SpawnError};
 use std::cell::{Ref, RefCell};
 
 /// An implementation of [`Spawn`](futures_task::Spawn) that records
@@ -10,7 +10,7 @@ use std::cell::{Ref, RefCell};
 /// use futures::task::SpawnExt;
 /// use futures_test::task::RecordSpawner;
 ///
-/// let mut recorder = RecordSpawner::new();
+/// let recorder = RecordSpawner::new();
 /// recorder.spawn(async { }).unwrap();
 /// assert_eq!(recorder.spawned().len(), 1);
 /// ```
@@ -32,10 +32,7 @@ impl RecordSpawner {
 }
 
 impl Spawn for RecordSpawner {
-    fn spawn_obj(
-        &self,
-        future: FutureObj<'static, ()>,
-    ) -> Result<(), SpawnError> {
+    fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
         self.spawned.borrow_mut().push(future);
         Ok(())
     }

futures-util/src/compat/executor.rs

@@ -1,21 +1,18 @@
-
 use super::{Compat, Future01CompatExt};
 use crate::{
     future::{FutureExt, TryFutureExt, UnitError},
     task::SpawnExt,
 };
+use futures_01::future::{ExecuteError as ExecuteError01, Executor as Executor01};
 use futures_01::Future as Future01;
-use futures_01::future::{Executor as Executor01, ExecuteError as ExecuteError01};
 use futures_task::{FutureObj, Spawn as Spawn03, SpawnError as SpawnError03};
 
 /// A future that can run on a futures 0.1
 /// [`Executor`](futures_01::future::Executor).
 pub type Executor01Future = Compat<UnitError<FutureObj<'static, ()>>>;
 
 /// Extension trait for futures 0.1 [`Executor`](futures_01::future::Executor).
-pub trait Executor01CompatExt: Executor01<Executor01Future> +
-                               Clone + Send + 'static
-{
+pub trait Executor01CompatExt: Executor01<Executor01Future> + Clone + Send + 'static {
     /// Converts a futures 0.1 [`Executor`](futures_01::future::Executor) into a
     /// futures 0.3 [`Spawn`](futures_task::Spawn).
     ///
@@ -27,7 +24,7 @@ pub trait Executor01CompatExt: Executor01<Executor01Future> +
     ///
     /// # let (tx, rx) = futures::channel::oneshot::channel();
     ///
-    /// let mut spawner = DefaultExecutor::current().compat();
+    /// let spawner = DefaultExecutor::current().compat();
     /// let future03 = async move {
     ///     println!("Running on the pool");
     ///     spawner.spawn(async {
@@ -42,39 +39,36 @@ pub trait Executor01CompatExt: Executor01<Executor01Future> +
     /// # futures::executor::block_on(rx).unwrap();
     /// ```
     fn compat(self) -> Executor01As03<Self>
-        where Self: Sized;
+    where
+        Self: Sized;
 }
 
 impl<Ex> Executor01CompatExt for Ex
-where Ex: Executor01<Executor01Future> + Clone + Send + 'static
+where
+    Ex: Executor01<Executor01Future> + Clone + Send + 'static,
 {
     fn compat(self) -> Executor01As03<Self> {
-        Executor01As03 {
-            executor01: self,
-        }
+        Executor01As03 { executor01: self }
     }
 }
 
 /// Converts a futures 0.1 [`Executor`](futures_01::future::Executor) into a
 /// futures 0.3 [`Spawn`](futures_task::Spawn).
 #[derive(Debug, Clone)]
 pub struct Executor01As03<Ex> {
-    executor01: Ex
+    executor01: Ex,
 }
 
 impl<Ex> Spawn03 for Executor01As03<Ex>
 where
     Ex: Executor01<Executor01Future> + Clone + Send + 'static,
 {
-    fn spawn_obj(
-        &self,
-        future: FutureObj<'static, ()>,
-    ) -> Result<(), SpawnError03> {
+    fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError03> {
         let future = future.unit_error().compat();
 
-        self.executor01.execute(future).map_err(|_|
-            SpawnError03::shutdown()
-        )
+        self.executor01
+            .execute(future)
+            .map_err(|_| SpawnError03::shutdown())
     }
 }
 
@@ -85,7 +79,8 @@ where
     Fut: Future01<Item = (), Error = ()> + Send + 'static,
 {
     fn execute(&self, future: Fut) -> Result<(), ExecuteError01<Fut>> {
-        (&self.inner).spawn(future.compat().map(|_| ()))
+        (&self.inner)
+            .spawn(future.compat().map(|_| ()))
             .expect("unable to spawn future from Compat executor");
         Ok(())
     }