bpo-37417: Fix error handling in bytearray.extend. (GH-14407)

(cherry picked from commit 2a7d596f27b2342caf168a03c95ebf3b56e5dbbd)

Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>

3 files changed, 11 insertions, 0 deletions

diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index c3f04ec..e0d2a69 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -1511,6 +1511,11 @@ class BuiltinTest(unittest.TestCase):
         self.assertRaises(ValueError, x.translate, b"1", 1)
         self.assertRaises(TypeError, x.translate, b"1"*256, 1)
 
+    def test_bytearray_extend_error(self):
+        array = bytearray()
+        bad_iter = map(int, "X")
+        self.assertRaises(ValueError, array.extend, bad_iter)
+
     def test_construct_singletons(self):
         for const in None, Ellipsis, NotImplemented:
             tp = type(const)
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-06-26-18-41-00.bpo-37417.VsZeHL.rst b/Misc/NEWS.d/next/Core and Builtins/2019-06-26-18-41-00.bpo-37417.VsZeHL.rst
new file mode 100644
index 0000000..f004631
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-06-26-18-41-00.bpo-37417.VsZeHL.rst
@@ -0,0 +1,2 @@
+:meth:`bytearray.extend` now correctly handles errors that arise during iteration.

+Patch by Brandt Bucher.
\ No newline at end of file
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 8a0994f..41de28d 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -1689,6 +1689,10 @@ bytearray_extend(PyByteArrayObject *self, PyObject *iterable_of_ints)
     }
     Py_DECREF(bytearray_obj);
 
+    if (PyErr_Occurred()) {
+        return NULL;
+    }
+
     Py_RETURN_NONE;
 }