582486 - nsPluginTag::RegisterWithCategoryManager unnecessarily reads a pref during XPCOM shutdown

Status: RESOLVED FIXED

(Core Graveyard :: Plug-ins, defect)

Description

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

RegisterWithCategoryManager() is called with aType==ePluginUnregister, and the method reads "plugin.disable_full_page_plugin_for_types" even though it doesn't use the computed values.  This isn't a major big deal, except that in DEBUG builds of content process, this can happen way after the IPC pipe is closed and the IPC shutdown code finished.  In the current implementation, this triggers a fatal assertion.  I'm filing this bug rather than adding a zillion checks to modules/libpref because I don't think we ought to be reading prefs on shutdown.

Comment 1

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Attachment: Don't read an unused pref when unregistering from the category manager

I should add to comment 0 that I'm not categorically against reading prefs on shutdown, but I'd need to come across a compelling use case before changing libpref.  This case isn't compelling because the value is unused.

Will look for approval+ upon r+.

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Comment on attachment 460770 [details] [diff] [review]
Don't read an unused pref when unregistering from the category manager

(By "approval2.0" here I have in mind fennec 2.0.)

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

http://hg.mozilla.org/mozilla-central/rev/6642cfe74e2c