420152 - Leaks shutting down Mochitest browser between tests

Status: NEW

(Core :: General, defect)

Description

[Jeff Walden [:Waldo]]

If I use the following commandline to run Mochitests with a debug build:

> python runtests.py --autorun --close-when-done --leak-threshold=0

I can pretty consistently trigger a leak by closing the browser immediately after the last MochiKit_Unit_Tests test (so I see a green line for that last test) but before the first browser test (test_bug395533.html) runs (so no green line displayed for it).

With the patch in a soon-to-be-filed bug, I get the following information about the leak (you'll still get told about the leak with the current runtests.py.in, but you'll have to dig the individual leaks out of the output yourself):

ERROR FAIL leaked 2024 bytes during test execution (should have leaked no more than 0 bytes)
ERROR FAIL leaked 1 instance of BackstagePass with size 24 bytes
ERROR FAIL leaked 1 instance of XPCNativeScriptableShared with size 108 bytes
ERROR FAIL leaked 12 instances of XPCWrappedNative with size 56 bytes each (672 bytes total)
ERROR FAIL leaked 4 instances of XPCWrappedNativeProto with size 28 bytes each (112 bytes total)
ERROR FAIL leaked 3 instances of nsArray with size 16 bytes each (48 bytes total)
ERROR FAIL leaked 1 instance of nsBaseAppShell with size 60 bytes
ERROR FAIL leaked 1 instance of nsBaseURLParser with size 12 bytes
ERROR FAIL leaked 1 instance of nsHashPropertyBag with size 48 bytes
ERROR FAIL leaked 3 instances of nsJSID with size 36 bytes each (108 bytes total)
ERROR FAIL leaked 1 instance of nsRunnable with size 12 bytes
ERROR FAIL leaked 2 instances of nsStandardURL with size 176 bytes each (352 bytes total)
ERROR FAIL leaked 10 instances of nsStringBuffer with size 8 bytes each (80 bytes total)
ERROR FAIL leaked 1 instance of nsSystemPrincipal with size 36 bytes
ERROR FAIL leaked 1 instance of nsThread with size 72 bytes
ERROR FAIL leaked 3 instances of nsVariant with size 48 bytes each (144 bytes total)
ERROR FAIL leaked 3 instances of nsVoidArray with size 4 bytes each (12 bytes total)
ERROR FAIL leaked 1 instance of nsXPCWrappedJS with size 60 bytes
ERROR FAIL leaked 1 instance of nsXPCWrappedJSClass with size 44 bytes
ERROR FAIL leaked 1 instance of xptiInterfaceInfo with size 20 bytes

Interestingly, although I usually get a leak of 2024 bytes, I've been able to get a 2012-byte leak exactly equivalent to this one except that it's not leaking the nsRunnable, so the exact magnitude of the leak is timing-dependent.

I don't have any idea who's at fault with this bug, so it's in the General cesspool for now.

Comment 1

[Jeff Walden [:Waldo]]

The extended leak information patch is in bug 420154.