806299 - Harmony proxies: can't return {configurable:true} from traps

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[David Bruant]

Test case:

  var p = new Proxy({}, {
      getOwnPropertyDescriptor: function(target, name){
          return {configurable: true};
      }
  });

  Object.getOwnPropertyDescriptor(p, 'a');

Expected result:
{value: undefined, writable: false, enumerable: false, configurable: true}

Actual result:
Error thrown with inaccurate message: "proxy can't report a new property on a non-extensible object" (while the target is actually extensible)

Comment 1

[David Bruant]

For the record, the title is a bit inaccurate. I've seen this message also when trying {configurable: false} and {event: true, configurable: false}. Both of these cases should fail (because the property is not non-configurable on the target), but with a different error message. I'm assuming fixing the bug with configurable:true will fix it for these cases too.

Comment 2

[Tom Van Cutsem]

I believe this may be a duplicate of bug 793210.

Comment 3

[Tom S [:evilpie]]

This was probably bug Bug 978238.