636789 - Object.defineProperty is not always transparent on proxies

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[David Anderson [:dvander] - inactive, e-mail if emergency]

Attachment: WIP v2

Object.defineProperty, on a proxy, goes through external API which doesn't have the right semantics. We should make it go through the right internal API, which is a little tricky since not enough data is passed around.

This patch passes Jeff's Object.defineProperty tests if I make it wrap incoming objects.

Brendan says:
> Could you go slightly further and s/ESPropertyDescriptor/PropDesc/g so we
> wouldn't have yet another such thing (albeit a subtype)? I.e., keep the subtype
> relation but merge the new one into the PropDesc one added to jsobj.* for ES5.

So I'll do that next.

Comment 2

[Jason Orendorff [:jorendorff]]

I hadn't seen this patch, and I went and reproduced about half of the work in jsdbg2 branch. I really should read this patch before landing that.

Btw, it turns out this was actually spec'd with the wrong semantics that we implement; I sent email to es-discuss and they fixed it in the wiki (hence the distinction between ToPropertyDescriptor and ToCompletePropertyDescriptor now).
  http://wiki.ecmascript.org/doku.php?id=harmony:proxies_semantics
So this bug was INVALID all this time, but not anymore. :-\

Comment 3

[Bryan Thrall [:bthrall]]

mozilla-unified central passes the Object.defineProperty tests if I patch s/src/tests/non262/object/defineProperty-setup.js line 403 like this:

-      Object.defineProperty(obj, propname, propdesc);
+      Object.defineProperty(wrapWithProto(obj, null), propname, propdesc);

So I think this issue has been resolved.