fix(codex): make stream error handler idempotent in sandbox exec processes

lsr911 · claude · lsr911 · commit 4d792f1e95ef · 2026-07-09T13:50:35.000+08:00
If both stdout and stderr emit errors, the second error would
overwrite the first failure message. Add an early return guard so
only the first stream error is preserved, matching the expected
behavior where Codex consumes process/read.failure.

Co-Authored-By: Claude &lt;noreply@anthropic.com&gt;
diff --git a/extensions/codex/src/app-server/sandbox-exec-server/processes.ts b/extensions/codex/src/app-server/sandbox-exec-server/processes.ts
@@ -120,6 +120,7 @@ async function runProcess(
   );
   child.stderr.on("data", (chunk: Buffer) => appendProcessChunk(managed, "stderr", chunk));
   const onStreamError = (error: Error) => {
+    if (managed.failure) return;
     managed.failure = error.message;
     emitProcessClosed(managed, null);
   };
