join handle await always propogates panic

crates/wasi/src/preview2/filesystem.rs

@@ -266,7 +266,6 @@ impl HostOutputStream for FileOutputStream {
         match std::pin::Pin::new(&mut self.task)
             .take_output()
             .expect("just awaited for MaybeDone completion")
-            .expect("FileOutputStream worker task panicked")
         {
             Ok(()) => Ok(FILE_WRITE_CAPACITY),
             Err(e) => {

crates/wasi/src/preview2/mod.rs

@@ -180,12 +180,17 @@ impl<T> From<tokio::task::JoinHandle<T>> for AbortOnDropJoinHandle<T> {
     }
 }
 impl<T> std::future::Future for AbortOnDropJoinHandle<T> {
-    type Output = Result<T, tokio::task::JoinError>;
+    type Output = T;
     fn poll(
         mut self: std::pin::Pin<&mut Self>,
         cx: &mut std::task::Context<'_>,
     ) -> std::task::Poll<Self::Output> {
-        std::pin::Pin::new(&mut self.as_mut().0).poll(cx)
+        use std::pin::Pin;
+        use std::task::Poll;
+        match Pin::new(&mut self.as_mut().0).poll(cx) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(r) => Poll::Ready(r.expect("child task panicked")),
+        }
     }
 }
 

crates/wasi/src/preview2/tcp.rs

@@ -184,12 +184,9 @@ impl HostOutputStream for TcpWriteStream {
     }
 
     async fn write_ready(&mut self) -> Result<usize, OutputStreamError> {
-        if self.write_handle.is_some() {
-            self.write_handle
-                .as_mut()
-                .unwrap()
+        if let Some(handle) = &mut self.write_handle {
+            handle
                 .await
-                .expect("TcpWriteStream worker panicked")
                 .map_err(|e| OutputStreamError::LastOperationFailed(e.into()))?;
 
             // Only clear out the write handle once the task has exited, to ensure that