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bpo-30570: Use Py_EnterRecursiveCall() in issubclass() #29048

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Merged
gpshead merged 3 commits into from
Oct 22, 2021
+45 −6
Merged

bpo-30570: Use Py_EnterRecursiveCall() in issubclass() #29048

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9c3276e
Use Py_EnterRecursiveCall() in issubclass()
sweeneyde Oct 19, 2021
21c5b0f
📜🤖 Added by blurb_it.
blurb-it[bot] Oct 19, 2021
f0cf002
Add an additional test case.
gpshead Oct 22, 2021
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Use Py_EnterRecursiveCall() in issubclass()
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@sweeneyde
sweeneyde committed Oct 19, 2021
commit 9c3276e99bcb3227d98945f567b6c3a2f6921abe
21 changes: 21 additions & 0 deletions Lib/test/test_isinstance.py
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Original file line number Diff line number Diff line change
Expand Up @@ -313,6 +313,27 @@ def __bases__(self):
self.assertRaises(RecursionError, issubclass, int, X())
self.assertRaises(RecursionError, isinstance, 1, X())

def test_infinite_cycle_in_bases(self):
# bpo-30570
class X:
@property
def __bases__(self):
return (self, self, self)
self.assertRaises(RecursionError, issubclass, X(), int)

def test_infinitely_many_bases(self):
# bpo-30570
class X:
def __getattr__(self, attr):
self.assertEqual(attr, "__bases__")
class A:
pass
class B:
pass
A.__getattr__ = B.__getattr__ = X.__getattr__
return (A(), B())
self.assertRaises(RecursionError, issubclass, X(), int)


def blowstack(fxn, arg, compare_to):
# Make sure that calling isinstance with a deeply nested tuple for its
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20 changes: 14 additions & 6 deletions Objects/abstract.c
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Expand Up @@ -2557,14 +2557,22 @@ abstract_issubclass(PyObject *derived, PyObject *cls)
derived = PyTuple_GET_ITEM(bases, 0);
continue;
}
for (i = 0; i < n; i++) {
r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls);
if (r != 0)
break;
}
break;
}
assert(n >= 2);
if (Py_EnterRecursiveCall(" in __issubclass__")) {
Py_DECREF(bases);
return r;
return -1;
}
for (i = 0; i < n; i++) {
r = abstract_issubclass(PyTuple_GET_ITEM(bases, i), cls);
if (r != 0) {
break;
}
}
Py_LeaveRecursiveCall();
Py_DECREF(bases);
return r;
}

static int
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