fix: require `Suspend::new()` to ensure the `Future` is properly scoped at creation time, not at render time

leptos_server/src/lib.rs

@@ -204,11 +204,11 @@ mod view_implementations {
         type State = RenderEffectState<SuspendState<T, R>>;
 
         fn build(self) -> Self::State {
-            (move || Suspend(async move { self.await })).build()
+            (move || Suspend::new(async move { self.await })).build()
         }
 
         fn rebuild(self, state: &mut Self::State) {
-            (move || Suspend(async move { self.await })).rebuild(state)
+            (move || Suspend::new(async move { self.await })).rebuild(state)
         }
     }
 
@@ -239,7 +239,7 @@ mod view_implementations {
         where
             Self::Output<NewAttr>: RenderHtml<R>,
         {
-            (move || Suspend(async move { self.await })).add_any_attr(attr)
+            (move || Suspend::new(async move { self.await })).add_any_attr(attr)
         }
     }
 
@@ -258,7 +258,7 @@ mod view_implementations {
         }
 
         fn resolve(self) -> impl Future<Output = Self::AsyncOutput> + Send {
-            (move || Suspend(async move { self.await })).resolve()
+            (move || Suspend::new(async move { self.await })).resolve()
         }
 
         fn to_html_with_buf(
@@ -267,7 +267,7 @@ mod view_implementations {
             position: &mut Position,
             escape: bool,
         ) {
-            (move || Suspend(async move { self.await }))
+            (move || Suspend::new(async move { self.await }))
                 .to_html_with_buf(buf, position, escape);
         }
 
@@ -279,7 +279,7 @@ mod view_implementations {
         ) where
             Self: Sized,
         {
-            (move || Suspend(async move { self.await }))
+            (move || Suspend::new(async move { self.await }))
                 .to_html_async_with_buf::<OUT_OF_ORDER>(buf, position, escape);
         }
 
@@ -288,7 +288,7 @@ mod view_implementations {
             cursor: &Cursor<R>,
             position: &PositionState,
         ) -> Self::State {
-            (move || Suspend(async move { self.await }))
+            (move || Suspend::new(async move { self.await }))
                 .hydrate::<FROM_SERVER>(cursor, position)
         }
     }

reactive_graph/src/computed/async_derived/mod.rs

@@ -20,11 +20,13 @@ use std::{
 pin_project! {
     /// A [`Future`] wrapper that sets the [`Owner`] and [`Observer`] before polling the inner
     /// `Future`.
+    #[derive(Clone)]
+    #[allow(missing_docs)]
     pub struct ScopedFuture<Fut> {
-        owner: Option<Owner>,
+        pub owner: Option<Owner>,
-        observer: Option<AnySubscriber>,
+        pub observer: Option<AnySubscriber>,
         #[pin]
-        fut: Fut,
+        pub fut: Fut,
     }
 }
 

tachys/src/reactive_graph/suspense.rs

@@ -21,7 +21,14 @@ use std::{cell::RefCell, fmt::Debug, future::Future, pin::Pin, rc::Rc};
 
 /// A suspended `Future`, which can be used in the view.
 #[derive(Clone)]
-pub struct Suspend<Fut>(pub Fut);
+pub struct Suspend<Fut>(pub ScopedFuture<Fut>); // TODO probably shouldn't be pub
+
+impl<Fut> Suspend<Fut> {
+    /// Creates a new suspended view.
+    pub fn new(fut: Fut) -> Self {
+        Self(ScopedFuture::new(fut))
+    }
+}
 
 impl<Fut> Debug for Suspend<Fut> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -69,7 +76,7 @@ where
         // poll the future once immediately
         // if it's already available, start in the ready state
         // otherwise, start with the fallback
-        let mut fut = Box::pin(ScopedFuture::new(self.0));
+        let mut fut = Box::pin(self.0);
         let initial = fut.as_mut().now_or_never();
         let initially_pending = initial.is_none();
         let inner = Rc::new(RefCell::new(initial.build()));
@@ -96,7 +103,7 @@ where
 
     fn rebuild(self, state: &mut Self::State) {
         // get a unique ID if there's a SuspenseContext
-        let fut = ScopedFuture::new(self.0);
+        let fut = self.0;
         let id = use_context::<SuspenseContext>().map(|sc| sc.task_id());
 
         // spawn the future, and rebuild the state when it resolves
@@ -137,10 +144,19 @@ where
         Self::Output<NewAttr>: RenderHtml<Rndr>,
     {
         let attr = attr.into_cloneable_owned();
-        Suspend(Box::pin(async move {
+        let ScopedFuture {
-            let this = self.0.await;
+            owner,
-            this.add_any_attr(attr)
+            observer,
-        }))
+            fut,
+        } = self.0;
+        Suspend(ScopedFuture {
+            owner,
+            observer,
+            fut: Box::pin(async move {
+                let this = fut.await;
+                this.add_any_attr(attr)
+            }),
+        })
     }
 }
 
@@ -234,7 +250,7 @@ where
         // poll the future once immediately
         // if it's already available, start in the ready state
         // otherwise, start with the fallback
-        let mut fut = Box::pin(ScopedFuture::new(self.0));
+        let mut fut = Box::pin(self.0);
         let initial = fut.as_mut().now_or_never();
         let initially_pending = initial.is_none();
         let inner = Rc::new(RefCell::new(