mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-10-09 16:34:44 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 17

bpo-29942: Fix the use of recursion in itertools.chain.from_iterable. (#912)

Browse source 
Fix the use of recursion in itertools.chain.from_iterable. Using recursion
is unnecessary, and can easily cause stack overflows, especially when
building in low optimization modes or with Py_DEBUG enabled.
(cherry picked from commit 5466d4af5f)
This commit is contained in:
T. Wouters 2017-03-30 12:48:55 -07:00 • committed by GitHub
parent 8b8bde44f3
commit 9273dfe180
3 changed files with 39 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

8
Lib/test/test_itertools.py
View file

@ -1943,6 +1943,14 @@ class RegressionTests(unittest.TestCase):
self.assertRaises(AssertionError, list, cycle(gen1()))
self.assertEqual(hist, [0,1])
def test_long_chain_of_empty_iterables(self):
# Make sure itertools.chain doesn't run into recursion limits when
# dealing with long chains of empty iterables. Even with a high
# number this would probably only fail in Py_DEBUG mode.
it = chain.from_iterable(() for unused in range(10000000))
with self.assertRaises(StopIteration):
next(it)
class SubclassWithKwargsTest(unittest.TestCase):
def test_keywords_in_subclass(self):
# count is not subclassable...