Issue 4509: Do not modify an array if we know the change would result
in a failure due to exported buffers.
diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 7ae34a9..eb1fffb 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -749,9 +749,25 @@
ArraySubclassWithKwargs('b', newarg=1)
def test_create_from_bytes(self):
+ # XXX This test probably needs to be moved in a subclass or
+ # generalized to use self.typecode.
a = array.array('H', b"1234")
self.assertEqual(len(a) * a.itemsize, 4)
+ def test_memoryview_no_resize(self):
+ # Test for issue 4509.
+ a = array.array(self.typecode, self.example)
+ m = memoryview(a)
+ expected = m.tobytes()
+ self.assertRaises(BufferError, a.pop, 0)
+ self.assertEqual(m.tobytes(), expected)
+ self.assertRaises(BufferError, a.remove, a[0])
+ self.assertEqual(m.tobytes(), expected)
+ self.assertRaises(BufferError, a.__setitem__, slice(0, 0), a)
+ self.assertEqual(m.tobytes(), expected)
+ self.assertRaises(BufferError, a.__delitem__, slice(0, len(a)))
+ self.assertEqual(m.tobytes(), expected)
+
class StringTest(BaseTest):
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 6dc46ad..256bcd8 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -735,6 +735,14 @@
ihigh = Py_SIZE(a);
item = a->ob_item;
d = n - (ihigh-ilow);
+ /* Issue #4509: If the array has exported buffers and the slice
+ assignment would change the size of the array, fail early to make
+ sure we don't modify it. */
+ if (d != 0 && a->ob_exports > 0) {
+ PyErr_SetString(PyExc_BufferError,
+ "cannot resize an array that is exporting buffers");
+ return -1;
+ }
if (d < 0) { /* Delete -d items */
memmove(item + (ihigh+d)*a->ob_descr->itemsize,
item + ihigh*a->ob_descr->itemsize,