Bug 28811 – callee and length properties of arguments object are missing the DontEnum attribute

• Component: JavaScriptCore
• Status: RESOLVED INVALID

[Kent Hansen]

According to ECMA-262, section 10.1.8, the callee and length properties have attributes { DontEnum }.

[Kent Hansen]

Created attachment 38736 [details]
Proposed patch

[Geoffrey Garen]

Comment on attachment 38736 [details]
Proposed patch

Code looks good.

However, please supply a ChangeLog and a regression test verifying this behavior.

More info @ http://webkit.org/coding/contributing.html.

[Oliver Hunt]

Comment on attachment 38736 [details]
Proposed patch

Why is this necessary? for..in does not enumerate the properties on arguments, getOwnPropertyDescriptor also reports it as false.

[Geoffrey Garen]

I think the problem is that propertyIsEnumerable would return true, but should return false.

I think the best way to fix this is to remove all use and implementation of getPropertyAttributes, and change propertyIsEnumerable to call getPropertyDescriptor instead.

[Kent Hansen]

(In reply to comment #3)
> (From update of attachment 38736 [details])
> Why is this necessary? for..in does not enumerate the properties on arguments,
> getOwnPropertyDescriptor also reports it as false.

(In reply to comment #4)
> I think the problem is that propertyIsEnumerable would return true, but should
> return false.
> 
> I think the best way to fix this is to remove all use and implementation of
> getPropertyAttributes, and change propertyIsEnumerable to call
> getPropertyDescriptor instead.

Agreed.
I originally did the patch before https://bugs.webkit.org/show_bug.cgi?id=28724 was fixed, and as Oliver said, getOwnPropertyDescriptor does the right thing already.

[Kent Hansen]

Following up on Geoffrey's recommended solution, created https://bugs.webkit.org/show_bug.cgi?id=31933