From 201adb7406d3265abd76f49c04dbafbf2ee00301 Mon Sep 17 00:00:00 2001
From: Greg Johnston <greg.johnston@gmail.com>
Date: Sat, 17 Feb 2024 16:50:23 -0500
Subject: [PATCH] clone values for Futures

---
 .../computed/async_derived/async_derived.rs   |  7 +++--
 .../computed/async_derived/future_impls.rs    | 26 +++++++++----------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/reactive_graph/src/computed/async_derived/async_derived.rs b/reactive_graph/src/computed/async_derived/async_derived.rs
index 81075f94a..ea2a7268d 100644
--- a/reactive_graph/src/computed/async_derived/async_derived.rs
+++ b/reactive_graph/src/computed/async_derived/async_derived.rs
@@ -135,8 +135,11 @@ impl<T: Send + Sync + 'static> DefinedAt for AsyncDerived<T> {
     }
 }
 
-impl<T: Send + Sync + Clone + 'static> IntoFuture for AsyncDerived<T> {
-    type Output = ReadGuard<T, Mapped<Plain<AsyncState<T>>, T>>;
+impl<T: Send + Sync + Clone + 'static> IntoFuture for AsyncDerived<T>
+where
+    T: Clone,
+{
+    type Output = T;
     type IntoFuture = AsyncDerivedFuture<T>;
 
     #[track_caller]
diff --git a/reactive_graph/src/computed/async_derived/future_impls.rs b/reactive_graph/src/computed/async_derived/future_impls.rs
index 43c5b7fb9..7ec7ab312 100644
--- a/reactive_graph/src/computed/async_derived/future_impls.rs
+++ b/reactive_graph/src/computed/async_derived/future_impls.rs
@@ -44,8 +44,11 @@ pub struct AsyncDerivedFuture<T> {
     wakers: Arc<RwLock<Vec<Waker>>>,
 }
 
-impl<T: 'static> IntoFuture for ArcAsyncDerived<T> {
-    type Output = ReadGuard<T, Mapped<Plain<AsyncState<T>>, T>>;
+impl<T> IntoFuture for ArcAsyncDerived<T>
+where
+    T: Clone + 'static,
+{
+    type Output = T;
     type IntoFuture = AsyncDerivedFuture<T>;
 
     fn into_future(self) -> Self::IntoFuture {
@@ -57,8 +60,13 @@ impl<T: 'static> IntoFuture for ArcAsyncDerived<T> {
     }
 }
 
-impl<T: 'static> Future for AsyncDerivedFuture<T> {
-    type Output = ReadGuard<T, Mapped<Plain<AsyncState<T>>, T>>;
+// this is implemented to output T by cloning it because read guards should not be held across
+// .await points, and it's way too easy to trip up by doing that!
+impl<T> Future for AsyncDerivedFuture<T>
+where
+    T: Clone + 'static,
+{
+    type Output = T;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let waker = cx.waker();
@@ -70,15 +78,7 @@ impl<T: 'static> Future for AsyncDerivedFuture<T> {
                 self.wakers.write().or_poisoned().push(waker.clone());
                 Poll::Pending
             }
-            AsyncState::Complete(_) => {
-                Poll::Ready(ReadGuard::new(Mapped::new(value, |inner| {
-                    match inner {
-                        AsyncState::Complete(value) => value,
-                        // we've just checked this value is Complete
-                        _ => unreachable!(),
-                    }
-                })))
-            }
+            AsyncState::Complete(value) => Poll::Ready(value.clone()),
         }
     }
 }