409433 - XPConnect should never allow GC off the main thread

Status: RESOLVED FIXED

(Core :: XPConnect, defect)

Description

[Benjamin Smedberg]

Attachment: XPConnect allows GC on the main thread only, rev. 1

xpconnect has some machinery to only allow GC to occur on the main thread. It is disabled in xpconnect by default, but our DOM turns it on. Because cycle collector is main-thread only we should not allow GC to ever occur off the main thread.

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

So, XPConnect is supposedly a standalone library that could have non-Gecko users. Do we really want to take this option away from them? Right now, I think we even build with XPCONNECT_STANDALONE, but I'm not sure. If we do this, are we going to take more steps towards making XPConnect a more Gecko-centric thing?

Comment 2

[Boris Zbarsky [:bzbarsky]]

I think it would make the most sense to force main thread if and only if cycle collector is in use by the xpconnect consumer.  Or is that always the case?

Comment 3

[Mike Shaver (:shaver emeritus)]

If we build with XPCONNECT_STANDALONE still, it's blind luck; if things work correctly.  I think we should take this patch and if there are consumers for standalone XPConnect, they shouldn't find it too hard to produce either a local hack or trunk-acceptable patch to make it not only build but also work.

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

Comment on attachment 294242 [details] [diff] [review]
XPConnect allows GC on the main thread only, rev. 1

All right, I accept shaver's argument. Is there a place where non-Gecko XPConnect users might hang out so we can announce this change?

Comment 5

[Benjamin Smedberg]

Fixed on trunk. I'll post to md.platform