diff options
| -rw-r--r-- | Lib/test/test_iter.py | 25 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2023-02-14-09-08-48.gh-issue-101892.FMos8l.rst | 3 | ||||
| -rw-r--r-- | Objects/iterobject.c | 4 |
3 files changed, 30 insertions, 2 deletions
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py index 3130ec5..f9935d6 100644 --- a/Lib/test/test_iter.py +++ b/Lib/test/test_iter.py @@ -346,6 +346,31 @@ class TestCase(unittest.TestCase): return i self.check_iterator(iter(spam, 20), list(range(10)), pickle=False) + def test_iter_function_concealing_reentrant_exhaustion(self): + # gh-101892: Test two-argument iter() with a function that + # exhausts its associated iterator but forgets to either return + # a sentinel value or raise StopIteration. + HAS_MORE = 1 + NO_MORE = 2 + + def exhaust(iterator): + """Exhaust an iterator without raising StopIteration.""" + list(iterator) + + def spam(): + # Touching the iterator with exhaust() below will call + # spam() once again so protect against recursion. + if spam.is_recursive_call: + return NO_MORE + spam.is_recursive_call = True + exhaust(spam.iterator) + return HAS_MORE + + spam.is_recursive_call = False + spam.iterator = iter(spam, NO_MORE) + with self.assertRaises(StopIteration): + next(spam.iterator) + # Test exception propagation through function iterator def test_exception_function(self): def spam(state=[0]): diff --git a/Misc/NEWS.d/next/Library/2023-02-14-09-08-48.gh-issue-101892.FMos8l.rst b/Misc/NEWS.d/next/Library/2023-02-14-09-08-48.gh-issue-101892.FMos8l.rst new file mode 100644 index 0000000..d586779 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-02-14-09-08-48.gh-issue-101892.FMos8l.rst @@ -0,0 +1,3 @@ +Callable iterators no longer raise :class:`SystemError` when the +callable object exhausts the iterator but forgets to either return a +sentinel value or raise :class:`StopIteration`. diff --git a/Objects/iterobject.c b/Objects/iterobject.c index 980c04b..ffea129 100644 --- a/Objects/iterobject.c +++ b/Objects/iterobject.c @@ -223,7 +223,7 @@ calliter_iternext(calliterobject *it) } result = _PyObject_CallNoArg(it->it_callable); - if (result != NULL) { + if (result != NULL && it->it_sentinel != NULL){ int ok; ok = PyObject_RichCompareBool(it->it_sentinel, result, Py_EQ); @@ -231,7 +231,6 @@ calliter_iternext(calliterobject *it) return result; /* Common case, fast path */ } - Py_DECREF(result); if (ok > 0) { Py_CLEAR(it->it_callable); Py_CLEAR(it->it_sentinel); @@ -242,6 +241,7 @@ calliter_iternext(calliterobject *it) Py_CLEAR(it->it_callable); Py_CLEAR(it->it_sentinel); } + Py_XDECREF(result); return NULL; } |