Help wanted: Membrane proxies + Object.freeze() == paradox

Alex Vincent ajvincent at
Tue May 23 20:42:09 UTC 2017

Thanks, Jason.  I tried that approach last night (calling setPrototypeOf
within the getPrototypeOf trap), and it caused a nasty regression in one of
my other prototype-checking tests.  I assumed at the time that I had done
something wrong, but your quick summary shows that instead I was doing
something right, and that my prototype chain handling was incorrectly

On Tue, May 23, 2017 at 9:26 AM, Jason Orendorff <jason.orendorff at>

> I think the most straightforward thing is something like this:
> To restate the obvious, this is a minimal fix for your minimized test
> case, not production code you can take and use. You'd need to implement all
> the rest of the handler methods.
> On Tue, May 23, 2017 at 11:01 AM, Alex Vincent <ajvincent at>
> wrote:
>> Yes, I've been using the shadow technique in my es7-membrane project for
>> quite some time.  I was trying to minimize a fairly complex test case here.
>> Obviously, I can reintroduce shadow targets into the minimal testcase,
>> but then I need to figure out how to make the prototype object I'm trying
>> to get consistent again... still working through the details of that in my
>> head.
>> On Tue, May 23, 2017 at 8:50 AM, Mark S. Miller <erights at>
>> wrote:
>>> Take a look at Tom's explanation of the "shadow target" technique at
>>> section 4.3
>>> --
>>>     Cheers,
>>>     --MarkM

"The first step in confirming there is a bug in someone else's work is
confirming there are no bugs in your own."
-- Alexander J. Vincent, June 30, 2001
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