Went back to named futures but now with must_use

embassy-sync/src/pubsub/mod.rs

@@ -562,7 +562,7 @@ mod tests {
     async fn correct_available() {
         let channel = PubSubChannel::<NoopRawMutex, u32, 4, 4, 4>::new();
 
-        let mut sub0 = channel.subscriber().unwrap();
+        let sub0 = channel.subscriber().unwrap();
         let mut sub1 = channel.subscriber().unwrap();
         let pub0 = channel.publisher().unwrap();
 

embassy-sync/src/pubsub/publisher.rs

@@ -31,12 +31,11 @@ impl<'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> Pub<'a, PSB, T> {
     }
 
     /// Publish a message. But if the message queue is full, wait for all subscribers to have read the last message
-    pub async fn publish<'s>(&'s self, message: T) {
+    pub fn publish<'s>(&'s self, message: T) -> PublisherWaitFuture<'s, 'a, PSB, T> {
         PublisherWaitFuture {
             message: Some(message),
             publisher: self,
         }
-        .await
     }
 
     /// Publish a message if there is space in the message queue
@@ -167,7 +166,8 @@ impl<'a, M: RawMutex, T: Clone, const CAP: usize, const SUBS: usize, const PUBS:
 }
 
 /// Future for the publisher wait action
-struct PublisherWaitFuture<'s, 'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> {
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct PublisherWaitFuture<'s, 'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> {
     /// The message we need to publish
     message: Option<T>,
     publisher: &'s Pub<'a, PSB, T>,

embassy-sync/src/pubsub/subscriber.rs

@@ -28,8 +28,8 @@ impl<'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> Sub<'a, PSB, T> {
     }
 
     /// Wait for a published message
-    pub async fn next_message(&mut self) -> WaitResult<T> {
-        SubscriberWaitFuture { subscriber: self }.await
+    pub fn next_message<'s>(&'s mut self) -> SubscriberWaitFuture<'s, 'a, PSB, T> {
+        SubscriberWaitFuture { subscriber: self }
     }
 
     /// Wait for a published message (ignoring lag results)
@@ -140,7 +140,8 @@ impl<'a, M: RawMutex, T: Clone, const CAP: usize, const SUBS: usize, const PUBS:
 }
 
 /// Future for the subscriber wait action
-struct SubscriberWaitFuture<'s, 'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> {
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct SubscriberWaitFuture<'s, 'a, PSB: PubSubBehavior<T> + ?Sized, T: Clone> {
     subscriber: &'s mut Sub<'a, PSB, T>,
 }