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Re: WindowProxy objects violate ES5 invariants

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Sat, 15 Dec 2012 12:48:39 -0500
Message-ID: <50CCB7F7.9050303@mit.edu>
To: David Bruant <bruant.d@gmail.com>
CC: public-script-coord@w3.org
On 12/15/12 12:42 PM, David Bruant wrote:
> In that context, I mean "reported by Object.getOwnPropertyDescriptor".
> You say "reported" below. It's the same idea.

Ah, OK.  I thought you were talking about what the property actually 
"is" on the object.  If we're just talking about 
getOwnPropertyDescriptor, which already lies like crazy in browsers, 
then I agree we need to figure out exactly it should lie here.

> The underlying window may change, but the same WindowProxy object must
> show some consistency. It's the same object (identity equality).

Sure.  I think we're in violent agreement here.

>> That would be the practical upshot of them being actually
>> non-configurable on the Window but the WindowProxy lying about it, yes.
> Interesting. That would be an interesting way to think of it from an
> implementation perspective. But as far as authors are concerned, the
> non-[Unforgeable] properties would always be reflected as configurable;
> no way to observe the Window/WindowProxy difference you describe.

Well, there are ways to observe it indirectly.  But yes, no way to 
invoke getOwnPropertyDescriptor on the Window directly.

-Boris
Received on Saturday, 15 December 2012 17:49:07 UTC

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