514445 - this._menu._teardown doesn't exist when we want to call it.

Status: NEW

(Thunderbird :: Toolbars and Tabs, defect)

Description

[Blake Winton (:bwinton) (:☕️)]

From https://bugzilla.mozilla.org/show_bug.cgi?id=465269#c38:
> The greater confusion and concern is that the code in the event notifications
> that checks if "this._menu._teardown" exists pretty much fails all the time
> and it seems like a great mystery to me as to why it is happening.  dumps
> (removed in the patch) suggest that this._menu._teardown is valid when it is
> registered as a listener, and a dump in the notification suggests that we are
> dealing with the same XUL object and wrapper (as this._menu) when the
> notification actually fires.
>
> I think we may have some other kind of listener leak on our hands, which is
> not terribly surprising given the mysterious disappearance of _teardown.
> Unfortunately, I may have caused this as a result of debugging code as I had
> accidentally removed one of the calls to removelistener.  I guess, just keep
> an eye out for this.  The only real good way to keep an eye on this is to
> break on "nsMsgMailSession::AddFolderListener" and take a look
> "*mListeners.mArray.mHdr" while you are in there.  You can compel the widget
> to be instantiated by right-click and choosing to add a new folder.  The new
> folder dialog uses the widget.  It is safer than using the folder-picker
> combobox, at least on linux, because GrabKeys happens for popups and then
> your X session becomes useless.
>
> I don't think the last 2 probably are immediately addressable, and they
> certainly are not new, but if you have any ideas, I'd be glad to hear them.
> Otherwise they too should probably get a bug.

And so here's the bug for them.

Some more info:
The calls are in mailnews/base/content/folderWidgets.xml, in <field name="_listener">'s OnItemAdded and OnItemRemoved methods.

Thanks,
Blake.

Comment 1

[:aceman]

We should check if this is still happening.
The folder picker code still does check if this._menu._teardown exists.