From 2a7d596f27b2342caf168a03c95ebf3b56e5dbbd Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandtbucher@gmail.com>
Date: Wed, 26 Jun 2019 12:06:18 -0700
Subject: [PATCH] bpo-37417: Fix error handling in bytearray.extend. (GH-14407)

---
 Lib/test/test_builtin.py                                     | 5 +++++
 .../2019-06-26-18-41-00.bpo-37417.VsZeHL.rst                 | 2 ++
 Objects/bytearrayobject.c                                    | 4 ++++
 3 files changed, 11 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-06-26-18-41-00.bpo-37417.VsZeHL.rst

diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index b536cec0648..61155799c44 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -1592,6 +1592,11 @@ 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 00000000000..f004631e236
--- /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 c684db76736..1bb19a9271b 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -1698,6 +1698,10 @@ bytearray_extend(PyByteArrayObject *self, PyObject *iterable_of_ints)
     }
     Py_DECREF(bytearray_obj);
 
+    if (PyErr_Occurred()) {
+        return NULL;
+    }
+
     Py_RETURN_NONE;
 }