From 052b7ed25c34023286929b098c2f81fdfcb1ab1d Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Wed, 2 Jan 2019 16:07:20 +0100
Subject: [PATCH] worker: improve JS-side debugging

Do not print debug messages that indicate that a stdio stream
has drained; because `util.debuglog()` uses `console.log`, which
in turn uses stdio streams, this would otherwise have lead to an
endless loop.
---
 lib/internal/worker/io.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/internal/worker/io.js b/lib/internal/worker/io.js
index d249ba8508b7af..ad8056b5b9108a 100644
--- a/lib/internal/worker/io.js
+++ b/lib/internal/worker/io.js
@@ -62,7 +62,8 @@ MessagePort.prototype.unref = MessagePortPrototype.unref;
 // .onmessage events, and a function used for sending data to a MessagePort
 // in some other thread.
 MessagePort.prototype[kOnMessageListener] = function onmessage(payload) {
-  debug(`[${threadId}] received message`, payload);
+  if (payload.type !== messageTypes.STDIO_WANTS_MORE_DATA)
+    debug(`[${threadId}] received message`, payload);
   // Emit the deserialized object to userland.
   this.emit('message', payload);
 };