From c7c9c8c8c15659c567921b86ff175fdfc2c5cef1 Mon Sep 17 00:00:00 2001
From: Christoph Herzog <chris@theduke.at>
Date: Thu, 2 Mar 2023 09:59:01 +0100
Subject: [PATCH] fix(wasi): WsaiThreadRunGuard: Don't overwrite finished state

Do not overwrite the finished state if the task already has a result.

Prevents mistakenly propagating errors from the WasiThreadRunGuard drop
implementation.
---
 lib/wasi/src/os/task/task_join_handle.rs | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/wasi/src/os/task/task_join_handle.rs b/lib/wasi/src/os/task/task_join_handle.rs
index be56cadb9e8..62b534caf05 100644
--- a/lib/wasi/src/os/task/task_join_handle.rs
+++ b/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();
     }