__proto__ and accessor descriptors

I would like to define custom getter and setter for `__proto__` property:

var obj = Object.defineProperty({}, '__proto__', {
    get : function () {return '__proto__ getter'},
    set : function (){return '__proto__ setter'}
});


console.log(obj.__proto__); //[object Object]
console.log(obj.__proto__ = {}); //[object Object]


I didn't find an engine which outputs the values in get and set. The idea
behind my code is to reject the `__proto__` ability to change the internal
[[Prototype]].

Is the above behavior should be observed according ECMAScript 6?

Thank you.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20121026/197fb974/attachment.html>

Le 26/10/2012 22:56, Asen Bozhilov a écrit :
> I would like to define custom getter and setter for `__proto__`
> property: 
>
> var obj = Object.defineProperty({}, '__proto__', {
>     get : function () {return '__proto__ getter'},
>     set : function (){return '__proto__ setter'}
> });
>
>
> console.log(obj.__proto__); //[object Object]
> console.log(obj.__proto__ = {}); //[object Object]
>
>
> I didn't find an engine which outputs the values in get and set.
On Firefox Aurora, I find:
"__proto__ getter"
"[object Object]"

> The idea behind my code is to reject the `__proto__` ability to change
> the internal [[Prototype]]
In conforming engines, 'delete Object.prototype.__proto__' will do the
job for all objects at the same time.

> Is the above behavior should be observed according ECMAScript 6? 
It is not, but it's likely that no implementation perfectly conforms.
Take a look at
http://wiki.ecmascript.org/doku.php?id=strawman:magic_proto_property
According to this strawman, the output should indeed be
"__proto__getter" then "__proto__setter".

David

On 10/26/2012 02:30 PM, David Bruant wrote:> Le 26/10/2012 22:56, Asen Bozhilov a écrit :
>> var obj = Object.defineProperty({}, '__proto__', {
>>     get : function () {return '__proto__ getter'},
>>     set : function (){return '__proto__ setter'}
>> });
>>
>>
>> console.log(obj.__proto__); //[object Object]
>> console.log(obj.__proto__ = {}); //[object Object]
>>
> On Firefox Aurora, I find:
> "__proto__ getter"
> "[object Object]"
> 
> According to this strawman, the output should indeed be
> "__proto__getter" then "__proto__setter".

Given that the result of evaluating |obj.__proto__ = {}| is the right-hand side (the return value of calling the setter is ignored), to the extent there's some determined-correct behavior here, it definitely wouldn't be to log "__proto__ setter".

Jeff

Jeff Walden wrote:
> On 10/26/2012 02:30 PM, David Bruant wrote:>  Le 26/10/2012 22:56, Asen Bozhilov a écrit :
>>> var obj = Object.defineProperty({}, '__proto__', {
>>>      get : function () {return '__proto__ getter'},
>>>      set : function (){return '__proto__ setter'}
>>> });
>>>
>>>
>>> console.log(obj.__proto__); //[object Object]
>>> console.log(obj.__proto__ = {}); //[object Object]
>>>
>> On Firefox Aurora, I find:
>> "__proto__ getter"
>> "[object Object]"
>>
>> According to this strawman, the output should indeed be
>> "__proto__getter" then "__proto__setter".
>
> Given that the result of evaluating |obj.__proto__ = {}| is the right-hand side (the return value of calling the setter is ignored), to the extent there's some determined-correct behavior here, it definitely wouldn't be to log "__proto__ setter".

Score! Good point.

David, if the setter calls console.log you should see the desired results.

/be

Le 09/11/2012 00:05, Jeff Walden a écrit :
> On 10/26/2012 02:30 PM, David Bruant wrote:> Le 26/10/2012 22:56, Asen Bozhilov a écrit :
>>> var obj = Object.defineProperty({}, '__proto__', {
>>>      get : function () {return '__proto__ getter'},
>>>      set : function (){return '__proto__ setter'}
>>> });
>>>
>>>
>>> console.log(obj.__proto__); //[object Object]
>>> console.log(obj.__proto__ = {}); //[object Object]
>>>
>> On Firefox Aurora, I find:
>> "__proto__ getter"
>> "[object Object]"
>>
>> According to this strawman, the output should indeed be
>> "__proto__getter" then "__proto__setter".
> Given that the result of evaluating |obj.__proto__ = {}| is the right-hand side (the return value of calling the setter is ignored), to the extent there's some determined-correct behavior here, it definitely wouldn't be to log "__proto__ setter".
Jeff m'a tuer [1]

David

[1] Reference to "Omar m'a tuer", a case in France where the victim 
would have written the name of her murderer (Omar) with her own blood 
right before dying... but made an absurd typo (it should be "tuée" 
instead of "tuer"). A film has been made out of the case if anyone's 
interested http://en.wikipedia.org/wiki/Omar_Killed_Me