Issue #14630: Fix an incorrect access of ob_digit[0] for a zero instance of an int subclass.
diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
index 04066ec..3ebc1f7 100644
--- a/Lib/test/test_long.py
+++ b/Lib/test/test_long.py
@@ -1148,6 +1148,20 @@
self.assertRaises(TypeError, myint.from_bytes, 0, 'big')
self.assertRaises(TypeError, int.from_bytes, 0, 'big', True)
+ def test_access_to_nonexistent_digit_0(self):
+ # http://bugs.python.org/issue14630: A bug in _PyLong_Copy meant that
+ # ob_digit[0] was being incorrectly accessed for instances of a
+ # subclass of int, with value 0.
+ class Integer(int):
+ def __new__(cls, value=0):
+ self = int.__new__(cls, value)
+ self.foo = 'foo'
+ return self
+
+ integers = [Integer(0) for i in range(1000)]
+ for n in map(int, integers):
+ self.assertEqual(n, 0)
+
def test_main():
support.run_unittest(LongTest)
diff --git a/Misc/NEWS b/Misc/NEWS
index addae1b..56d4876 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
Core and Builtins
-----------------
+- Issue #14630: Fix a memory access bug for instances of a subclass of int
+ with value 0.
+
- Issue #14612: Fix jumping around with blocks by setting f_lineno.
- Issue #14607: Fix keyword-only arguments which started with ``__``.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index a0b16a6..a735e33 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -156,9 +156,7 @@
if (i < 0)
i = -(i);
if (i < 2) {
- sdigit ival = src->ob_digit[0];
- if (Py_SIZE(src) < 0)
- ival = -ival;
+ sdigit ival = MEDIUM_VALUE(src);
CHECK_SMALL_INT(ival);
}
result = _PyLong_New(i);