Bug 147930 – X.[[SetPrototypeOf]](Y) should succeed if X.[[Prototype]] is already Y even if X is not extensible

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[ziyunfei]

js> var proto = {}
js> var obj = Object.preventExtensions(Object.create(proto))
js> Object.setPrototypeOf(obj ,proto)
TypeError: Attempted to assign to readonly property. // should return obj
js> Reflect.setPrototypeOf(obj, proto)
false // should be true

[Yusuke Suzuki]

(In reply to comment #0)
> js> var proto = {}
> js> var obj = Object.preventExtensions(Object.create(proto))
> js> Object.setPrototypeOf(obj ,proto)
> TypeError: Attempted to assign to readonly property. // should return obj
> js> Reflect.setPrototypeOf(obj, proto)
> false // should be true

Nice catch!
We need to fix
1. Object.setPrototypeOf
2. Reflect.setPrototypeOf
3. object.__proto__ = ...

[Yusuke Suzuki]

Created attachment 258886 [details]
Patch

[Saam Barati]

Comment on attachment 258886 [details]
Patch

r=me

[Yusuke Suzuki]

Comment on attachment 258886 [details]
Patch

Thank you!

[WebKit Commit Bot]

Comment on attachment 258886 [details]
Patch

Clearing flags on attachment: 258886

Committed r188384: <http://trac.webkit.org/changeset/188384>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.