400786 - Proto bindings hold (unjustified) weak refs to other proto bindings

Status: RESOLVED WONTFIX

(Core :: XBL, defect, P3)

Description

[Boris Zbarsky [:bzbarsky]]

nsXBLPrototypeBinding::mBaseBinding is a weak ref.  But this can be to a binding owned by some totally different document info, so there's nothing guaranteeing it will stay alive.

We probably need to make this a strong ref and cycle-collect accordingly.

Comment 1

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Do you know off hand what needs to be added to the cycle collector?

Comment 2

[Boris Zbarsky [:bzbarsky]]

That's a really good question.  One issue here is that nsXBLPrototypeBinding itself is not refcounted and not cycle collected.

I guess traversing an nsXBLDocumentInfo would need to walk its proto binding hashtable, and for each one traverse to the nsXBLDocumentInfo of the mBaseBinding.  That would reflect how things are owned, I think.

Not sure what the safest way to Unlink would be.

Comment 3

[Boris Zbarsky [:bzbarsky]]

XBL is now disabled in Firefox (Bug 1583314) and is in the process of being removed from Gecko (Bug 1566221), so closing bugs requesting changes to its implementation as wontfix.