Bug 18737 – __lookupSetter__ and __lookupGetter__ don't work for getting native setters and getters

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: JavaScriptCore

[Michael A. Puls II]

Safari 3.1 (525.13) with WebKit-SVN-r32486.

Getting native setters and getters works in Firefox.

[Michael A. Puls II]

It doesn't work on instances either.

javascript:alert(document.createAttribute("instance").__lookupGetter__("value"))

That works in FF and Opera 9.5.

[Sam Weinig]

The reason this does not work is that value is a not a getter/setter, but rather an attribute.  It is an implementation detail that Firefox implements native attributes as getter/setter functions.  Changing our implementation to do this would be a probable performance hit, so I can only really see doing this if there is a real world need.

[Michael A. Puls II]

(In reply to comment #2)
> The reason this does not work is that value is a not a getter/setter, but
> rather an attribute.  It is an implementation detail that Firefox implements
> native attributes as getter/setter functions.  Changing our implementation to
> do this would be a probable performance hit, so I can only really see doing
> this if there is a real world need.
> 

Would making it work for instances be acceptable, or would that be just as much as a performance concern?

[Michael A. Puls II]

Created attachment 22467 [details]
Example that works in Opera 9.5 and Firefox 3, but not in Safari with latest webkit

(In reply to comment #2)
> so I can only really see doing
> this if there is a real world need.

See the source of the attachment for an example.

If not, how bout just for compatibility with Firefox and Opera?

Or, maybe try out the change and see how much performance is affected? (Maybe it'd be acceptable?)

[Michael A. Puls II]

(In reply to comment #1)
> It doesn't work on instances either.
> 
> javascript:alert(document.createAttribute("instance").__lookupGetter__("value"))
> 
> That works in FF and Opera 9.5.
> 

This works in Opera 9.5+, Firefox and IE8 beta 2.

javascript:alert(document.createTextNode("instance").__lookupGetter__("nodeValue"))

[Alexey Proskuryakov]

See also: bug 12721.

[Gavin Barraclough]

The problem here isn't that __lookupGetter__/Setter are doing the wrong thing, the problem is that the properties aren't actually accessors (but per the WebIDL spec should be).

*** This bug has been marked as a duplicate of bug 49739 ***