Crashers of the day: Py_CLEAR must be used when there is a chance that the
function can be called recursively.
This was discussed in issue1020188.
In python codebase, all occurrences of Py_[X]DECREF(xxx->yyy) are suspect,
except when they appear in tp_new or tp_dealloc functions, or when
the member cannot be of a user-defined class.
Note that tp_init is not safe.
I do have a (crashing) example for every changed line.
Is it worth adding them to the test suite?
Example:
class SpecialStr(str):
def __del__(self):
s.close()
import cStringIO
s = cStringIO.StringIO(SpecialStr("text"))
s.close() # Segfault
diff --git a/Modules/cStringIO.c b/Modules/cStringIO.c
index 3529047..139a4a8 100644
--- a/Modules/cStringIO.c
+++ b/Modules/cStringIO.c
@@ -575,8 +575,7 @@
static PyObject *
I_close(Iobject *self, PyObject *unused) {
- Py_XDECREF(self->pbuf);
- self->pbuf = NULL;
+ Py_CLEAR(self->pbuf);
self->buf = NULL;
self->pos = self->string_size = 0;