wasi: Thread Lifecycle Fix

lib/wasi/src/bin_factory/exec.rs

@@ -1,7 +1,7 @@
 use std::{pin::Pin, sync::Arc};
 
 use crate::{
-    os::task::{thread::WasiThreadGuard, TaskJoinHandle},
+    os::task::{thread::WasiThreadRunGuard, TaskJoinHandle},
     VirtualBusError, WasiRuntimeError,
 };
 use futures::Future;
@@ -120,7 +120,7 @@ pub fn spawn_exec_module(
                     }
                 };
 
-                let thread = WasiThreadGuard::new(wasi_env.thread.clone());
+                let thread = WasiThreadRunGuard::new(wasi_env.thread.clone());
 
                 let mut wasi_env = WasiFunctionEnv::new(&mut store, wasi_env);
 

lib/wasi/src/os/task/task_join_handle.rs

@@ -38,6 +38,14 @@ impl TaskStatus {
             _ => None,
         }
     }
+
+    /// Returns `true` if the task status is [`Finished`].
+    ///
+    /// [`Finished`]: TaskStatus::Finished
+    #[must_use]
+    pub fn is_finished(&self) -> bool {
+        matches!(self, Self::Finished(..))
+    }
 }
 
 #[derive(thiserror::Error, Debug)]
@@ -88,6 +96,11 @@ impl OwnedTaskStatus {
 
     /// Marks the task as finished.
     pub(super) fn set_finished(&self, res: Result<ExitCode, Arc<WasiRuntimeError>>) {
+        // Don't overwrite a previous finished state.
+        if self.status().is_finished() {
+            return;
+        }
+
         let inner = match res {
             Ok(code) => Ok(code),
             Err(err) => {
@@ -98,7 +111,6 @@ impl OwnedTaskStatus {
                 }
             }
         };
-
         self.watch.send(TaskStatus::Finished(inner)).ok();
     }
 

lib/wasi/src/os/task/thread.rs

@@ -96,17 +96,17 @@ pub struct WasiThread {
 /// [`Thread::set_status_running`] or [`Thread::set_status_finished`], but
 /// this guard can ensure that the thread is marked as terminated even if this
 /// is forgotten or a panic occurs.
-pub struct WasiThreadGuard {
+pub struct WasiThreadRunGuard {
     pub thread: WasiThread,
 }
 
-impl WasiThreadGuard {
+impl WasiThreadRunGuard {
     pub fn new(thread: WasiThread) -> Self {
         Self { thread }
     }
 }
 
-impl Drop for WasiThreadGuard {
+impl Drop for WasiThreadRunGuard {
     fn drop(&mut self) {
         self.thread
             .set_status_finished(Err(