Skip to content

bpo-38525: Fix segfault when using reverse iterators of empty dict literals #16847

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
pablogsal wants to merge 1 commit into from
Closed

bpo-38525: Fix segfault when using reverse iterators of empty dict literals #16847

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions Lib/test/test_dict.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1154,6 +1154,19 @@ def test_reversevaluesiterator_pickling(self):
values = list(it) + [drop]
self.assertEqual(sorted(values), sorted(data.values()))

def test_reverseiterator_empty_dict(self):
# Check bpo-38525

the_dict = {}
self.assertEqual(list(reversed(the_dict)), list())
self.assertEqual(list(reversed(the_dict.values())), list())
self.assertEqual(list(reversed(the_dict.keys())), list())

the_dict = dict()
self.assertEqual(list(reversed(the_dict)), list())
self.assertEqual(list(reversed(the_dict.values())), list())
self.assertEqual(list(reversed(the_dict.keys())), list())

def test_instance_dict_getattr_str_subclass(self):
class Foo:
def __init__(self, msg):
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2019-10-19-15-58-26.bpo-38525.rmOpTg.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix a segmentation fault when using reverse iterators of empty ``dict``
objects that were created as empty dict literals. Patch by Pablo Galindo.
2 changes: 1 addition & 1 deletion Objects/dictobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3826,7 +3826,7 @@ dictreviter_iternext(dictiterobject *di)
PyObject *key, *value, *result;

if (d->ma_values) {
if (i < 0) {
if (i < 0 || i >= d->ma_used) {
goto fail;
}
key = DK_ENTRIES(k)[i].me_key;
Expand Down