Recursively fixing a Harmony proxy should be short-circuited by throwing a TypeError, to safeguard against infinite loops. For instance: var proxy = Proxy.create({ fix: function() { Object.preventExtensions(proxy); // triggers 'fix()' recursively return {}; } }); Object.preventExtensions(proxy); // triggers 'fix' Result: InternalError: too much recursion Expected: a TypeError We reached consensus on this behavior in a TC39 meeting last year. Admittedly, it's well hidden on the semantics page: <http://wiki.ecmascript.org/doku.php?id=harmony:proxies_semantics> "Note: recursive fixing should be disallowed. If fix() is called on a proxy handler while the same proxy is already being fixed (an earlier call to fix() is already on the stack), a TypeError should be thrown. "

So it looks like the code to do this properly is already present, but in the wrong spot. I have no way of accessing tryserver or a recent tree, so this patch may not apply or be correct. If someone (gal?) could try applying it and see if it solves the problem, I would be mighty appreciative.

Andreas, want to own this till Josh returns? /be

Tested; this works correctly.

Comment on attachment 530403 [details] [diff] [review] Check proxy operations before fixing object. Nice patch. Thanks!

We need a regression test for this bug. http://hg.mozilla.org/tracemonkey/rev/6855db79531d does not include one.

cdleary-bot mozilla-central merge info: http://hg.mozilla.org/mozilla-central/rev/6855db79531d Note: not marking as fixed because fixed-in-tracemonkey is not present on the whiteboard.