From 0906e074426fc596cffb157e28be4bf82de62c7b Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Wed, 7 Aug 2002 20:42:09 +0000 Subject: Fix a subtle bug in the trashcan code I added yesterday to subtype_dealloc(). When call_finalizer() failed, it would return without going through the trashcan end macro, thereby unbalancing the trashcan nesting level counter, and thereby defeating the test case (slottrash() in test_descr.py). This in turn meant that the assert in the GC_UNTRACK macro wasn't triggered by the slottrash() test despite a bug in the code: _PyTrash_destroy_chain() calls the dealloc routine with an object that's untracked, and the assert in the GC_UNTRACK macro would fail on this; but because of an earlier test that resurrects an object, causing call_finalizer() to fail and the trashcan nesting level to be unbalanced, so _PyTrash_destroy_chain() was never called. Calling the slottrash() test in isolation *did* trigger the assert, however. So the fix is twofold: (1) call the GC_UnTrack() function instead of the GC_UNTRACK macro, because the function is safe when the object is already untracked; (2) when call_finalizer() fails, jump to a label that exits through the trashcan end macro, keeping the trashcan nesting balanced. --- Objects/typeobject.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Objects/typeobject.c b/Objects/typeobject.c index b7edb14..d494344 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -463,13 +463,13 @@ subtype_dealloc(PyObject *self) /* We get here only if the type has GC */ /* UnTrack and re-Track around the trashcan macro, alas */ - _PyObject_GC_UNTRACK(self); + PyObject_GC_UnTrack(self); Py_TRASHCAN_SAFE_BEGIN(self); _PyObject_GC_TRACK(self); /* We'll untrack for real later */ /* Maybe call finalizer; exit early if resurrected */ if (call_finalizer(self) < 0) - return; + goto endlabel; /* Find the nearest base with a different tp_dealloc and clear slots while we're at it */ @@ -508,6 +508,7 @@ subtype_dealloc(PyObject *self) /* Can't reference self beyond this point */ Py_DECREF(type); + endlabel: Py_TRASHCAN_SAFE_END(self); } -- cgit v0.12