Figuring out the behavior of WindowProxy in the face of non-configurable properties

Boris Zbarsky bzbarsky at
Thu Dec 4 02:58:46 PST 2014

On 11/30/14, 6:12 PM, Mark S. Miller wrote:
> On Sun, Nov 30, 2014 at 12:21 PM, Boris Zbarsky <bzbarsky at> wrote:
>> Per spec ES6, it seems to me like attempting to define a non-configurable
>> property on a WindowProxy should throw and getting a property descriptor for
>> a non-configurable property that got defined on the Window (e.g. via "var")
>> should report it as configurable.
> Yes, both of these conclusions are correct.

OK.  What do we do if we discover that throwing from the defineProperty 
call with a non-configurable property descriptor is not web-compatible? 
  I'm going to try doing it in Firefox, and would welcome other UAs 
doing it ASAP to figure out whether we're in that situation.


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