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Fix SF#1470508: crash in generator cycle finalization. There were two

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problems: first, PyGen_NeedsFinalizing() had an off-by-one bug that
prevented it from ever saying a generator didn't need finalizing, and
second, frame objects cleared themselves in a way that caused their
owning generator to think they were still executable, causing a double
deallocation of objects on the value stack if there was still a loop
on the block stack.  This revision also removes some unnecessary
close() operations from test_generators that are now appropriately
handled by the cycle collector.
This commit is contained in:
Phillip J. Eby 2006-04-15 01:02:17 +00:00
parent 3cfea2dc98
commit 8ebb28df3a
3 changed files with 22 additions and 26 deletions
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21
Objects/genobject.c
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@ -35,7 +35,7 @@ gen_dealloc(PyGenObject *gen)
}
_PyObject_GC_UNTRACK(self);
Py_XDECREF(gen->gi_frame);
Py_CLEAR(gen->gi_frame);
PyObject_GC_Del(gen);
}
@ -130,8 +130,8 @@ gen_close(PyGenObject *gen, PyObject *args)
"generator ignored GeneratorExit");
return NULL;
}
if ( PyErr_ExceptionMatches(PyExc_StopIteration)
|| PyErr_ExceptionMatches(PyExc_GeneratorExit) )
if ( PyErr_ExceptionMatches(PyExc_StopIteration)
|| PyErr_ExceptionMatches(PyExc_GeneratorExit) )
{
PyErr_Clear(); /* ignore these errors */
Py_INCREF(Py_None);
@ -208,7 +208,7 @@ PyDoc_STRVAR(throw_doc,
return next yielded value or raise StopIteration.");
static PyObject *
gen_throw(PyGenObject *gen, PyObject *args)
gen_throw(PyGenObject *gen, PyObject *args)
{
PyObject *typ;
PyObject *tb = NULL;
@ -328,7 +328,7 @@ PyTypeObject PyGen_Type = {
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
@ -366,15 +366,16 @@ PyGen_NeedsFinalizing(PyGenObject *gen)
int i;
PyFrameObject *f = gen->gi_frame;
if (f == NULL || f->f_stacktop==NULL || f->f_iblock<=0)
return 0; /* no frame or no blockstack == no finalization */
if (f == NULL || f->f_stacktop == NULL || f->f_iblock <= 0)
return 0; /* no frame or empty blockstack == no finalization */
for (i=f->f_iblock; i>=0; i--) {
/* Any block type besides a loop requires cleanup. */
i = f->f_iblock;
while (--i >= 0) {
if (f->f_blockstack[i].b_type != SETUP_LOOP)
/* any block type besides a loop requires cleanup */
return 1;
}
/* No blocks except loops, it's safe to skip finalization */
/* No blocks except loops, it's safe to skip finalization. */
return 0;
}