1754372 - PermissionStatus with registered "change" listeners shouldn't be GC'd

Status: RESOLVED INVALID

(Core :: Permission Manager, defect, P3)

Description

[marcos]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.3 Safari/605.1.15

Steps to reproduce:

It should be possible to get a PermissionStatus object, register a listener on it, and allow it to go out of scope (but not have it GC'd)

For example:

(async () => {
  const perm = await navigator.permissions.query({ name: "geolocation" });
  perm.onchange = () => { console.log("pass") };
  console.log("going out of scope");
  // bye bye perm
})();

// prompts for permission
navigator.geolocation.getCurrentPosition(console.log);

Actual results:

Changing the permission of Geolocation in the above does nothing (so presumedly "perm" got CG'ed).

Expected results:

Changing the permission of Geolocation in the above should produce "pass" in the developer console.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:timhuang, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 2

[Kaiido]

Attachment: test-case.html

That doesn't seem GC related, the same happens even when holding a strong reference to the PermissionStatus object (see attachement). The issue looks more like onchange is not supported at all here, contrarily to what compat data states.

Comment 3

[Andrea Marchesini [:baku]]

This bug is invalid. PermissionStatus calls KeepAliveIfHasListenersFor in the CTOR: https://searchfox.org/mozilla-central/source/dom/permission/PermissionStatus.cpp#24