Issue #26494: Fixed crash on iterating exhausting iterators.
Affected classes are generic sequence iterators, iterators of str, bytes,
bytearray, list, tuple, set, frozenset, dict, OrderedDict, corresponding
views and os.scandir() iterator.
diff --git a/Lib/test/seq_tests.py b/Lib/test/seq_tests.py
index 2416249..72f4845 100644
--- a/Lib/test/seq_tests.py
+++ b/Lib/test/seq_tests.py
@@ -5,6 +5,7 @@
import unittest
import sys
import pickle
+from test import support
# Various iterables
# This is used for checking the constructor (here and in test_deque.py)
@@ -408,3 +409,7 @@
lst2 = pickle.loads(pickle.dumps(lst, proto))
self.assertEqual(lst2, lst)
self.assertNotEqual(id(lst2), id(lst))
+
+ def test_free_after_iterating(self):
+ support.check_free_after_iterating(self, iter, self.type2test)
+ support.check_free_after_iterating(self, reversed, self.type2test)
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index b82f9cb..e124fab 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2366,3 +2366,22 @@
"memory allocations")
import _testcapi
return _testcapi.run_in_subinterp(code)
+
+
+def check_free_after_iterating(test, iter, cls, args=()):
+ class A(cls):
+ def __del__(self):
+ nonlocal done
+ done = True
+ try:
+ next(it)
+ except StopIteration:
+ pass
+
+ done = False
+ it = iter(A(*args))
+ # Issue 26494: Shouldn't crash
+ test.assertRaises(StopIteration, next, it)
+ # The sequence should be deallocated just after the end of iterating
+ gc_collect()
+ test.assertTrue(done)
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index 80798f2..1bd3a1e 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -747,6 +747,10 @@
self.assertRaisesRegex(TypeError, r'\bendswith\b', b.endswith,
x, None, None, None)
+ def test_free_after_iterating(self):
+ test.support.check_free_after_iterating(self, iter, self.type2test)
+ test.support.check_free_after_iterating(self, reversed, self.type2test)
+
class BytesTest(BaseBytesTest, unittest.TestCase):
type2test = bytes
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index ec2be83..7041d17 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -905,6 +905,10 @@
# For now, bypass tests that require slicing
pass
+ def test_free_after_iterating(self):
+ # For now, bypass tests that require slicing
+ self.skipTest("Exhausted deque iterator doesn't free a deque")
+
#==============================================================================
libreftest = """
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 3b42414..075cb5a 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -952,6 +952,12 @@
d = {X(): 0, 1: 1}
self.assertRaises(RuntimeError, d.update, other)
+ def test_free_after_iterating(self):
+ support.check_free_after_iterating(self, iter, dict)
+ support.check_free_after_iterating(self, lambda d: iter(d.keys()), dict)
+ support.check_free_after_iterating(self, lambda d: iter(d.values()), dict)
+ support.check_free_after_iterating(self, lambda d: iter(d.items()), dict)
+
from test import mapping_tests
class GeneralMappingTests(mapping_tests.BasicTestMappingProtocol):
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 56e21f8..54ddbaa 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -3,6 +3,7 @@
import sys
import unittest
from test.support import run_unittest, TESTFN, unlink, cpython_only
+from test.support import check_free_after_iterating
import pickle
import collections.abc
@@ -980,6 +981,9 @@
self.assertEqual(next(it), 0)
self.assertEqual(next(it), 1)
+ def test_free_after_iterating(self):
+ check_free_after_iterating(self, iter, SequenceClass, (0,))
+
def test_main():
run_unittest(TestCase)
diff --git a/Lib/test/test_ordered_dict.py b/Lib/test/test_ordered_dict.py
index 8ab0a9f..901d4b2 100644
--- a/Lib/test/test_ordered_dict.py
+++ b/Lib/test/test_ordered_dict.py
@@ -598,6 +598,12 @@
gc.collect()
self.assertIsNone(r())
+ def test_free_after_iterating(self):
+ support.check_free_after_iterating(self, iter, self.OrderedDict)
+ support.check_free_after_iterating(self, lambda d: iter(d.keys()), self.OrderedDict)
+ support.check_free_after_iterating(self, lambda d: iter(d.values()), self.OrderedDict)
+ support.check_free_after_iterating(self, lambda d: iter(d.items()), self.OrderedDict)
+
class PurePythonOrderedDictTests(OrderedDictTests, unittest.TestCase):
diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
index 54de508..0b99dfc 100644
--- a/Lib/test/test_set.py
+++ b/Lib/test/test_set.py
@@ -362,6 +362,9 @@
gc.collect()
self.assertTrue(ref() is None, "Cycle was not collected")
+ def test_free_after_iterating(self):
+ support.check_free_after_iterating(self, iter, self.thetype)
+
class TestSet(TestJointOps, unittest.TestCase):
thetype = set
basetype = set
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index c30310e..c281146 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -2729,6 +2729,10 @@
# Check that the second call returns the same result
self.assertEqual(getargs_s_hash(s), chr(k).encode() * (i + 1))
+ def test_free_after_iterating(self):
+ support.check_free_after_iterating(self, iter, str)
+ support.check_free_after_iterating(self, reversed, str)
+
class StringModuleTest(unittest.TestCase):
def test_formatter_parser(self):
diff --git a/Misc/NEWS b/Misc/NEWS
index 59c0828..391bbf2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,11 @@
Core and Builtins
-----------------
+- Issue #26494: Fixed crash on iterating exhausting iterators.
+ Affected classes are generic sequence iterators, iterators of str, bytes,
+ bytearray, list, tuple, set, frozenset, dict, OrderedDict, corresponding
+ views and os.scandir() iterator.
+
- Issue #26581: If coding cookie is specified multiple times on a line in
Python source code file, only the first one is taken to account.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 710bcde..c95668b 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -11928,13 +11928,15 @@
static void
ScandirIterator_close(ScandirIterator *iterator)
{
- if (iterator->handle == INVALID_HANDLE_VALUE)
+ HANDLE handle = iterator->handle;
+
+ if (handle == INVALID_HANDLE_VALUE)
return;
- Py_BEGIN_ALLOW_THREADS
- FindClose(iterator->handle);
- Py_END_ALLOW_THREADS
iterator->handle = INVALID_HANDLE_VALUE;
+ Py_BEGIN_ALLOW_THREADS
+ FindClose(handle);
+ Py_END_ALLOW_THREADS
}
static PyObject *
@@ -11984,13 +11986,15 @@
static void
ScandirIterator_close(ScandirIterator *iterator)
{
- if (!iterator->dirp)
+ DIR *dirp = iterator->dirp;
+
+ if (!dirp)
return;
- Py_BEGIN_ALLOW_THREADS
- closedir(iterator->dirp);
- Py_END_ALLOW_THREADS
iterator->dirp = NULL;
+ Py_BEGIN_ALLOW_THREADS
+ closedir(dirp);
+ Py_END_ALLOW_THREADS
return;
}
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index c59ad24..c723a9c 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -3186,8 +3186,8 @@
return item;
}
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 51d0871..495c3eb 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -3628,8 +3628,8 @@
return item;
}
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index e4dff98..d774586 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2985,8 +2985,8 @@
return key;
fail:
- Py_DECREF(d);
di->di_dict = NULL;
+ Py_DECREF(d);
return NULL;
}
@@ -3066,8 +3066,8 @@
return value;
fail:
- Py_DECREF(d);
di->di_dict = NULL;
+ Py_DECREF(d);
return NULL;
}
@@ -3161,8 +3161,8 @@
return result;
fail:
- Py_DECREF(d);
di->di_dict = NULL;
+ Py_DECREF(d);
return NULL;
}
diff --git a/Objects/iterobject.c b/Objects/iterobject.c
index 2fb0c88..ab29ff8 100644
--- a/Objects/iterobject.c
+++ b/Objects/iterobject.c
@@ -69,8 +69,8 @@
PyErr_ExceptionMatches(PyExc_StopIteration))
{
PyErr_Clear();
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
}
return NULL;
}
diff --git a/Objects/listobject.c b/Objects/listobject.c
index eee7c68..d688179 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2782,8 +2782,8 @@
return item;
}
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}
@@ -2912,9 +2912,17 @@
listreviter_next(listreviterobject *it)
{
PyObject *item;
- Py_ssize_t index = it->it_index;
- PyListObject *seq = it->it_seq;
+ Py_ssize_t index;
+ PyListObject *seq;
+ assert(it != NULL);
+ seq = it->it_seq;
+ if (seq == NULL) {
+ return NULL;
+ }
+ assert(PyList_Check(seq));
+
+ index = it->it_index;
if (index>=0 && index < PyList_GET_SIZE(seq)) {
item = PyList_GET_ITEM(seq, index);
it->it_index--;
@@ -2922,10 +2930,8 @@
return item;
}
it->it_index = -1;
- if (seq != NULL) {
- it->it_seq = NULL;
- Py_DECREF(seq);
- }
+ it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}
diff --git a/Objects/setobject.c b/Objects/setobject.c
index 582f280..4ef692d 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -839,8 +839,8 @@
return key;
fail:
- Py_DECREF(so);
si->si_set = NULL;
+ Py_DECREF(so);
return NULL;
}
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 7efa1a6..7920fec 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -964,8 +964,8 @@
return item;
}
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index adc4615..230125b 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -15149,8 +15149,8 @@
return item;
}
- Py_DECREF(seq);
it->it_seq = NULL;
+ Py_DECREF(seq);
return NULL;
}