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

Andreas Rossberg rossberg at google.com
Tue Dec 2 04:59:32 PST 2014


On 1 December 2014 at 03:12, Mark S. Miller <erights at google.com> wrote:
> On Sun, Nov 30, 2014 at 12:21 PM, Boris Zbarsky <bzbarsky at mit.edu> 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.

Can you clarify? Do you mean that it should report properties as
configurable, but still reject attempts to actually reconfigure them?
Also, how would you allow 'var' to even define non-configurable
properties? If you want DefineProperty to throw on any such attempt,
then 'var' semantics would somehow have to bypass the MOP.

> From prior similar experiences, the way to get this fixed quickly is
> to add test262 tests which fail on these violations. All browsers have
> been much quicker to fix breakage that shows up in test262 results
> than to mere bug reports.

Well, let's find a workable semantics first. :)

/Andreas


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