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bpo-36473: add maximum iteration check for dict .values() and .items() (GH-12619)

This commit is contained in:
Thomas Perl 2019-04-02 11:30:10 +02:00 committed by Inada Naoki
parent 04694a306b
commit b8311cf5e5
3 changed files with 36 additions and 2 deletions
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20
Lib/test/test_dict.py
View File

@ -477,7 +477,25 @@ class DictTest(unittest.TestCase):
with self.assertRaises(RuntimeError):
for i in d:
del d[0]
d[1] = 1
d[0] = 0
def test_mutating_iteration_delete_over_values(self):
# change dict content during iteration
d = {}
d[0] = 0
with self.assertRaises(RuntimeError):
for i in d.values():
del d[0]
d[0] = 0
def test_mutating_iteration_delete_over_items(self):
# change dict content during iteration
d = {}
d[0] = 0
with self.assertRaises(RuntimeError):
for i in d.items():
del d[0]
d[0] = 0
def test_mutating_lookup(self):
# changing dict during a lookup (issue #14417)

6
Misc/NEWS.d/next/Core and Builtins/2019-03-27-23-53-00.bpo-36452.xhK2lT.rst
View File

@ -1 +1,5 @@
Changing `dict` keys during iteration will now be detected in certain corner cases where the number of keys isn't changed (but they keys themselves are), and a `RuntimeError` will be raised.
Changing ``dict`` keys during iteration of the dict itself, ``keys()``,
``values()``, or ``items()`` will now be detected in certain corner cases where
keys are deleted/added so that the number of keys isn't changed.
A `RuntimeError` will be raised after ``len(dict)`` iterations.
Contributed by Thomas Perl.

12
Objects/dictobject.c
View File

@ -3630,6 +3630,12 @@ dictiter_iternextvalue(dictiterobject *di)
goto fail;
value = entry_ptr->me_value;
}
// We found an element, but did not expect it
if (di->len == 0) {
PyErr_SetString(PyExc_RuntimeError,
"dictionary keys changed during iteration");
goto fail;
}
di->di_pos = i+1;
di->len--;
Py_INCREF(value);
@ -3713,6 +3719,12 @@ dictiter_iternextitem(dictiterobject *di)
key = entry_ptr->me_key;
value = entry_ptr->me_value;
}
// We found an element, but did not expect it
if (di->len == 0) {
PyErr_SetString(PyExc_RuntimeError,
"dictionary keys changed during iteration");
goto fail;
}
di->di_pos = i+1;
di->len--;
Py_INCREF(key);