[Webkit-unassigned] [Bug 234282] New: iOS Safari confused about whether 'showModalDialog' is own property of globalThis

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=234282

            Bug ID: 234282
           Summary: iOS Safari confused about whether 'showModalDialog' is
                    own property of globalThis
           Product: WebKit
           Version: Safari 15
          Hardware: iPhone / iPad
                OS: iOS 15
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: erights at gmail.com

At https://jsfiddle.net/kryLa94b/ we have the code

console.log(Object.getOwnPropertyNames(globalThis).includes('showModalDialog'));
console.log(Object.getOwnPropertyDescriptor(globalThis, 'showModalDialog'));

The first line tests whether `'showModalDialog'` is a property of the global object. The second line gets its own property descriptor. 

If there is no such own property, as seen for example on Brave on MacOS, the answers are `false` and `undefined`, which is consistent. 

If there is such an own property, as seen for example on Safari 15.1 on MacOS 12.0.1, the answers are

```
true
{
  configurable: true,
  enumerable: true,
  value: function showModalDialog() {
    [native code]
  },
  writable: true
}
```
which is consistent.

However, on iOS 15.1, the answers are `true` and `undefined`. These are inconsistent answers. Is there such an own property or not.

See also https://github.com/endojs/endo/issues/947 where Ash Connell originally reported this bug.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20211214/3de4cf7a/attachment.htm>