Bug 304996 – WebTransportError constructor mishandles single options argument and treats it as message

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[ankshit]

When WebTransportError is constructed with a single options object argument, the object is incorrectly interpreted as the message parameter and stringified to "[object Object]", rather than being recognized as the options dictionary.

```
  // Fail
  const e1 = new WebTransportError({ streamErrorCode: 42 });
  console.log(e1.streamErrorCode);         // null (expected: 42)
  console.log(e1.message);                      // "[object Object]" (expected: "")

  // Pass
  const e2 = new WebTransportError('test error', { streamErrorCode: 42 });
  console.log(e2.streamErrorCode);       // 42 (expected: 42)
  console.log(e2.message);                     // "test error" (expected: "test error")
```

The IDL interface correctly marks both arguments as optional:
```
interface WebTransportError : DOMException {
    constructor(optional DOMString message = "", optional WebTransportErrorOptions options = {});

    readonly attribute WebTransportErrorSource source;
    readonly attribute unsigned long? streamErrorCode;
};
```

[Alex Christensen]

This seems to be an issue with the generated JSWebTransportErrorDOMConstructor::construct.  I'm not sure if we have other functions with multiple optional arguments of different types, but it should try to line up the types.

[Radar WebKit Bug Importer]

<rdar://problem/167662230>

[Alex Christensen]

Pull request: https://github.com/WebKit/WebKit/pull/56176

[EWS]

Committed 305306@main (d6cbf74934a6): <https://commits.webkit.org/305306@main>

Reviewed commits have been landed. Closing PR #56176 and removing active labels.