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Code Issues Projects Releases Packages Wiki Activity Actions 21

only fast-path fromkeys() when the constructor returns a empty dict (closes #16345)

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This commit is contained in:
Benjamin Peterson 2012-10-31 14:05:55 -04:00
parent bdf1b9e267
commit 0ec820fc5f
3 changed files with 45 additions and 33 deletions
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8
Lib/test/test_dict.py
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@ -254,6 +254,14 @@ class DictTest(unittest.TestCase):
d = dict(zip(range(6), range(6)))
self.assertEqual(dict.fromkeys(d, 0), dict(zip(range(6), [0]*6)))
class baddict3(dict):
def __new__(cls):
return d
d = {i : i for i in range(10)}
res = d.copy()
res.update(a=None, b=None, c=None)
self.assertEqual(baddict3.fromkeys({"a", "b", "c"}), res)
def test_copy(self):
d = {1:1, 2:2, 3:3}
self.assertEqual(d.copy(), {1:1, 2:2, 3:3})

3
Misc/NEWS
View file

@ -12,6 +12,9 @@ Core and Builtins
- Issue #14700: Fix buggy overflow checks for large width and precision
in string formatting operations.
- Issue #16345: Fix an infinite loop when ``fromkeys`` on a dict subclass
recieved a nonempty dict from the constructor.
- Issue #6074: Ensure cached bytecode files can always be updated by the
user that created them, even when the source file is read-only.

67
Objects/dictobject.c
View file

@ -1353,49 +1353,50 @@ dict_fromkeys(PyObject *cls, PyObject *args)
if (d == NULL)
return NULL;
if (PyDict_CheckExact(d) && PyDict_CheckExact(seq)) {
PyDictObject *mp = (PyDictObject *)d;
PyObject *oldvalue;
Py_ssize_t pos = 0;
PyObject *key;
long hash;
if (PyDict_CheckExact(d) && PyDict_Size(d) == 0) {
if (PyDict_CheckExact(seq)) {
PyDictObject *mp = (PyDictObject *)d;
PyObject *oldvalue;
Py_ssize_t pos = 0;
PyObject *key;
long hash;
if (dictresize(mp, Py_SIZE(seq))) {
Py_DECREF(d);
return NULL;
}
while (_PyDict_Next(seq, &pos, &key, &oldvalue, &hash)) {
Py_INCREF(key);
Py_INCREF(value);
if (insertdict(mp, key, hash, value)) {
if (dictresize(mp, Py_SIZE(seq))) {
Py_DECREF(d);
return NULL;
}
while (_PyDict_Next(seq, &pos, &key, &oldvalue, &hash)) {
Py_INCREF(key);
Py_INCREF(value);
if (insertdict(mp, key, hash, value)) {
Py_DECREF(d);
return NULL;
}
}
return d;
}
return d;
}
if (PyAnySet_CheckExact(seq)) {
PyDictObject *mp = (PyDictObject *)d;
Py_ssize_t pos = 0;
PyObject *key;
long hash;
if (PyDict_CheckExact(d) && PyAnySet_CheckExact(seq)) {
PyDictObject *mp = (PyDictObject *)d;
Py_ssize_t pos = 0;
PyObject *key;
long hash;
if (dictresize(mp, PySet_GET_SIZE(seq))) {
Py_DECREF(d);
return NULL;
}
while (_PySet_NextEntry(seq, &pos, &key, &hash)) {
Py_INCREF(key);
Py_INCREF(value);
if (insertdict(mp, key, hash, value)) {
if (dictresize(mp, PySet_GET_SIZE(seq))) {
Py_DECREF(d);
return NULL;
}
while (_PySet_NextEntry(seq, &pos, &key, &hash)) {
Py_INCREF(key);
Py_INCREF(value);
if (insertdict(mp, key, hash, value)) {
Py_DECREF(d);
return NULL;
}
}
return d;
}
return d;
}
it = PyObject_GetIter(seq);