1655917 - Nuking a CCW to a WeakRef clears the target of the WeakRef

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect, P1)

Description

[Jon Coppeard (:jonco)]

As reported by loganfsmyth:

var g = newGlobal({ newCompartment: true });
g.eval(`
  var obj = {};
  var ref = new WeakRef(obj);
  Promise.resolve().then(() => {
    print(obj);
    print(ref.deref());
  });
`);
nukeCCW(g.ref);

Prints:

[object Object]
undefined

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1655917 - Fix clearing WeakRef target when CCWs to the WeakRef are nuked r?sfink

This was indisciminate before. We only want to do this when it's a CCW that's used by the WeakRef implementation that gets nuked.

Comment 2

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

Set release status flags based on info from the regressing bug 1644985

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/52f23f1d2acf
Fix clearing WeakRef target when CCWs to the WeakRef are nuked r=sfink

Comment 4

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/52f23f1d2acf

Comment 5

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

The patch landed in nightly and beta is affected.
:jonco, is this bug important enough to require an uplift?
If not please set status_beta to wontfix.

For more information, please visit auto_nag documentation.

Comment 6

[Jon Coppeard (:jonco)]

I think it's unlikely that there is still script running in compartments after we have nuked the CCWs to them and therefore this bug is unlikely to affect users. Let's let this ride the trains unless there's any evidence to the contrary.