Fix web_features example and issue with error propagation

Author: rscarson

Cargo.toml

@@ -253,6 +253,10 @@ required-features = ["worker"]
 name = "default_threaded_worker"
 required-features = ["worker"]
 
+[[example]]
+name = "web_features"
+required-features = ["web"]
+
 [[example]]
 name = "worker_pool"
 required-features = ["worker"]

src/inner_runtime.rs

@@ -645,33 +645,33 @@ impl<RT: RuntimeTrait> InnerRuntime<RT> {
     {
         // Manually implement tokio::select
         std::future::poll_fn(|cx| {
-            if let Poll::Ready(t) = fut.poll_unpin(cx) {
-                return if let Poll::Ready(Err(e)) =
-                    self.deno_runtime().poll_event_loop(cx, poll_options)
-                {
-                    // Run one more tick to check for errors
+            let evt_status = self.deno_runtime().poll_event_loop(cx, poll_options);
+            let fut_status = fut.poll_unpin(cx);
+
+            match (evt_status, fut_status) {
+                (Poll::Ready(Err(e)), _) => {
+                    // Event loop failed
                     Poll::Ready(Err(e.into()))
-                } else {
-                    // No errors - continue
-                    Poll::Ready(t.map_err(Into::into))
-                };
-            }
+                }
 
-            if let Poll::Ready(Err(e)) = self.deno_runtime().poll_event_loop(cx, poll_options) {
-                // Event loop failed
-                return Poll::Ready(Err(e.into()));
-            }
+                (_, Poll::Pending) => {
+                    // Continue polling
+                    Poll::Pending
+                }
 
-            if self
-                .deno_runtime()
-                .poll_event_loop(cx, poll_options)
-                .is_ready()
-            {
-                // Event loop resolved - continue
-                println!("Event loop resolved");
-            }
+                (_, Poll::Ready(t)) => {
+                    for _ in 0..100 {
+                        if let Poll::Ready(Err(e)) =
+                            self.deno_runtime().poll_event_loop(cx, poll_options)
+                        {
+                            return Poll::Ready(Err(e.into()));
+                        }
+                    }
 
-            Poll::Pending
+                    // Future resolved
+                    Poll::Ready(t.map_err(Into::into))
+                }
+            }
         })
         .await
     }
@@ -1257,6 +1257,27 @@ mod test_inner_runtime {
         });
     }
 
+    #[test]
+    fn test_deep_error() {
+        let module = Module::new(
+            "test.js",
+            "
+            await new Promise(r => setTimeout(r)); throw 'huh';
+        ",
+        );
+
+        let mut runtime =
+            InnerRuntime::<JsRuntime>::new(RuntimeOptions::default(), CancellationToken::new())
+                .expect("Could not load runtime");
+
+        let rt = &mut runtime;
+        run_async_task(|| async move {
+            let result = rt.load_modules(Some(&module), vec![]).await;
+            assert!(result.is_err());
+            Ok(())
+        });
+    }
+
     #[test]
     fn test_serialize_deep_fn() {
         let module = Module::new(