Make spawned futures falliable, and report those errors.

core/src/avm1.rs

@@ -1638,7 +1638,7 @@ impl<'gc> Avm1<'gc> {
             let slot = self.forcibly_root_object(context.layers[level_id].object().as_object()?);
 
             context.navigator.spawn_future(Box::pin(async move {
-                let data = fetch.await.unwrap();
+                let data = fetch.await?;
                 let movie = Arc::new(SwfMovie::from_data(&data));
 
                 player.lock().unwrap().update(|avm, uc| {
@@ -1660,6 +1660,8 @@ impl<'gc> Avm1<'gc> {
                                 crate::character::Character::MorphShape(morph_shape),
                             );
                     }
+
+                    Ok(())
                 })
             }));
 
@@ -1713,14 +1715,16 @@ impl<'gc> Avm1<'gc> {
                 let slot = self.forcibly_root_object(target_obj);
 
                 context.navigator.spawn_future(Box::pin(async move {
-                    let data = fetch.await.unwrap();
+                    let data = fetch.await?;
 
                     player.lock().unwrap().update(|avm, uc| {
                         let that = avm.unroot_object(slot);
 
                         for (k, v) in form_urlencoded::parse(&data) {
-                            that.set(&k, v.into_owned().into(), avm, uc);
+                            that.set(&k, v.into_owned().into(), avm, uc)?;
                         }
+
+                        Ok(())
                     })
                 }));
             }
@@ -1733,7 +1737,7 @@ impl<'gc> Avm1<'gc> {
                 let slot = self.forcibly_root_object(clip_target.object().as_object()?);
 
                 context.navigator.spawn_future(Box::pin(async move {
-                    let data = fetch.await.unwrap();
+                    let data = fetch.await?;
                     let movie = Arc::new(SwfMovie::from_data(&data));
 
                     player.lock().unwrap().update(|avm, uc| {
@@ -1755,6 +1759,8 @@ impl<'gc> Avm1<'gc> {
                                     crate::character::Character::MorphShape(morph_shape),
                                 );
                         }
+
+                        Ok(())
                     })
                 }))
             }

core/src/backend/navigator.rs

@@ -69,7 +69,7 @@ pub trait NavigatorBackend {
     ///
     /// TODO: For some reason, `wasm_bindgen_futures` wants unpinnable futures.
     /// This seems highly limiting.
-    fn spawn_future(&mut self, future: Pin<Box<dyn Future<Output = ()> + 'static>>);
+    fn spawn_future(&mut self, future: Pin<Box<dyn Future<Output = Result<(), Error>> + 'static>>);
 }
 
 /// A null implementation for platforms that do not live in a web browser.
@@ -100,5 +100,9 @@ impl NavigatorBackend for NullNavigatorBackend {
         Box::pin(async { Err("Fetch IO not implemented".into()) })
     }
 
-    fn spawn_future(&mut self, _future: Pin<Box<dyn Future<Output = ()> + 'static>>) {}
+    fn spawn_future(
+        &mut self,
+        _future: Pin<Box<dyn Future<Output = Result<(), Error>> + 'static>>,
+    ) {
+    }
 }

desktop/src/navigator.rs

@@ -67,7 +67,10 @@ impl NavigatorBackend for ExternalNavigatorBackend {
         Box::pin(async { Err("Fetch not implemented on desktop!".into()) })
     }
 
-    fn spawn_future(&mut self, _future: Pin<Box<dyn Future<Output = ()> + 'static>>) {
+    fn spawn_future(
+        &mut self,
+        _future: Pin<Box<dyn Future<Output = Result<(), Error>> + 'static>>,
+    ) {
         unimplemented!();
     }
 }

web/src/navigator.rs

@@ -99,7 +99,11 @@ impl NavigatorBackend for WebNavigatorBackend {
         })
     }
 
-    fn spawn_future(&mut self, future: Pin<Box<dyn Future<Output = ()> + 'static>>) {
+    fn spawn_future(&mut self, future: Pin<Box<dyn Future<Output = Result<(), Error>> + 'static>>) {
-        spawn_local(future)
+        spawn_local(async move {
+            if let Err(e) = future.await {
+                log::error!("Asynchronous error occured: {}", e);
+            }
+        })
     }
 }