From 77435b08a41aad28344440ac83ef710345085d4b Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc@chromium.org>
Date: Wed, 25 Sep 2024 09:16:46 -0700
Subject: [PATCH] library_pthread.js: Ensure transferredCanvasNames is iterable

This was first broken back in #17577 and then fixed in #17752.

I then broke it again in #22545 (yay!) (see #22620).

This time I will include a test to ensure this doesn't happen again.
---
 src/library_pthread.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/library_pthread.js b/src/library_pthread.js
index 680a6ac9dd316..7b797d68d6f4a 100644
--- a/src/library_pthread.js
+++ b/src/library_pthread.js
@@ -716,8 +716,8 @@ var LibraryPThread = {
       transferredCanvasNames = '{{{ OFFSCREENCANVASES_TO_PTHREAD }}}';
     } else
 #endif
-    transferredCanvasNames &&= UTF8ToString(transferredCanvasNames).trim();
-    transferredCanvasNames &&= transferredCanvasNames.split(',');
+    // Note: UTF8ToString(0) will return the empty string.
+    transferredCanvasNames = UTF8ToString(transferredCanvasNames).trim().split(',';
 #if GL_DEBUG
     dbg(`pthread_create: transferredCanvasNames="${transferredCanvasNames}"`);
 #endif