From bb8f59a37148eb81ef1a1a26a6fb6e1e03583d12 Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Mon, 3 Dec 2001 19:33:25 +0000
Subject: [PATCH] unpack_iterable(): Add a missing DECREF in an error case. 
 Reported by Armin Rigo (SF bug #488477).  Added a testcase to
 test_unpack_iter() in test_iter.py.

---
 Lib/test/test_iter.py | 23 +++++++++++++++++++++++
 Python/ceval.c        |  1 +
 2 files changed, 24 insertions(+)

diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 5bd7ba44a5..13ed5bd4a8 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -747,6 +747,29 @@ class TestCase(unittest.TestCase):
         (a, b), (c,) = IteratingSequenceClass(2), {42: 24}
         self.assertEqual((a, b, c), (0, 1, 42))
 
+        # Test reference count behavior
+
+        class C(object):
+            count = 0
+            def __new__(cls):
+                cls.count += 1
+                return object.__new__(cls)
+            def __del__(self):
+                cls = self.__class__
+                assert cls.count > 0
+                cls.count -= 1
+        x = C()
+        self.assertEqual(C.count, 1)
+        del x
+        self.assertEqual(C.count, 0)
+        l = [C(), C(), C()]
+        self.assertEqual(C.count, 3)
+        try:
+            a, b = iter(l)
+        except ValueError:
+            pass
+        del l
+        self.assertEqual(C.count, 0)
 
 def test_main():
     run_unittest(TestCase)
diff --git a/Python/ceval.c b/Python/ceval.c
index fd602b0a32..b41ef5a71e 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2796,6 +2796,7 @@ unpack_iterable(PyObject *v, int argcnt, PyObject **sp)
 		Py_DECREF(it);
 		return 1;
 	}
+	Py_DECREF(w);
 	PyErr_SetString(PyExc_ValueError, "too many values to unpack");
 	/* fall through */
 Error:
-- 
2.50.1