An object with __call__ as an attribute, when called, will have that attribute checked for __call__ itself, and will continue to look until it finds an object without the attribute. This can lead to an infinite recursion.

Closes bug #532646, again.  Will be backported.
This commit is contained in:
Brett Cannon 2006-06-09 22:31:23 +00:00
parent b2afe855e5
commit 22565aac3b
4 changed files with 30 additions and 9 deletions

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@ -1,9 +0,0 @@
# http://python.org/sf/1202533
class A(object):
pass
A.__call__ = A()
if __name__ == '__main__':
A()() # segfault: infinite recursion in C

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@ -3171,6 +3171,21 @@ def kwdargs():
list.__init__(a, sequence=[0, 1, 2])
vereq(a, [0, 1, 2])
def recursive__call__():
if verbose: print ("Testing recursive __call__() by setting to instance of "
"class ...")
class A(object):
pass
A.__call__ = A()
try:
A()()
except RuntimeError:
pass
else:
raise TestFailed("Recursion limit should have been reached for "
"__call__()")
def delhook():
if verbose: print "Testing __del__ hook..."
log = []
@ -4164,6 +4179,7 @@ def test_main():
buffer_inherit()
str_of_str_subclass()
kwdargs()
recursive__call__()
delhook()
hashinherit()
strops()

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@ -12,6 +12,12 @@ What's New in Python 2.5 beta 1?
Core and builtins
-----------------
- Bug #532646: object.__call__() will continue looking for the __call__
attribute on objects until one without one is found. This leads to recursion
when you take a class and set its __call__ attribute to an instance of the
class. Originally fixed for classic classes, but this fix is for new-style.
Removes the infinite_rec_3 crasher.
- The string and unicode methods startswith() and endswith() now accept
a tuple of prefixes/suffixes to look for. Implements RFE #1491485.

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@ -1790,7 +1790,15 @@ PyObject_Call(PyObject *func, PyObject *arg, PyObject *kw)
ternaryfunc call;
if ((call = func->ob_type->tp_call) != NULL) {
/* slot_tp_call() will be called and ends up calling
PyObject_Call() if the object returned for __call__ has
__call__ itself defined upon it. This can be an infinite
recursion if you set __call__ in a class to an instance of
it. */
if (Py_EnterRecursiveCall(" in __call__"))
return NULL;
PyObject *result = (*call)(func, arg, kw);
Py_LeaveRecursiveCall();
if (result == NULL && !PyErr_Occurred())
PyErr_SetString(
PyExc_SystemError,