Bug 263621

Summary:	Log to the console when preventDefault() is called inside a passive event listener
Product:	WebKit	Reporter:	Abrar Rahman Protyasha <a_protyasha>
Component:	DOM	Assignee:	Abrar Rahman Protyasha <a_protyasha>
Status:	NEW ---
Severity:	Normal	CC:	a_protyasha, karlcow, webkit-bug-importer
Priority:	P2	Keywords:	BrowserCompat, InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description Abrar Rahman Protyasha 2023-10-24 15:51:54 PDT

The DOM standard makes this recommendation:

```
There are scenarios where invoking preventDefault() has no effect. User agents are encouraged to log the precise cause in a developer console, to aid debugging.
```

We should respect that for the case when preventDefault() is called on an event inside a passive event listener, since that has no effect and might not be what the developer is expecting.

Comment 1 Radar WebKit Bug Importer 2023-10-24 15:52:05 PDT

<rdar://problem/117440707>

Comment 2 Abrar Rahman Protyasha 2023-10-24 15:58:16 PDT

(In reply to Abrar Rahman Protyasha from comment #0)
> The DOM standard makes this recommendation:

Recommendation is here:

https://dom.spec.whatwg.org/#set-the-canceled-flag:~:text=There%20are%20scenarios%20where%20invoking%20preventDefault()%20has%20no%20effect.%20User%20agents%20are%20encouraged%20to%20log%20the%20precise%20cause%20in%20a%20developer%20console%2C%20to%20aid%20debugging.

Comment 3 Abrar Rahman Protyasha 2023-10-24 15:59:14 PDT

This change should also bring us to parity with behavior in Blink/Gecko.

Comment 4 Abrar Rahman Protyasha 2023-10-24 16:12:20 PDT

Pull request: https://github.com/WebKit/WebKit/pull/19514