From a3c30a78f12bc9dcaeb59b49ae1c55d992ef9984 Mon Sep 17 00:00:00 2001
From: Malek <lekmalek@gmail.com>
Date: Tue, 1 May 2018 08:02:46 +0200
Subject: [PATCH 1/2] fix leak in set_symmetric_difference

---
 Objects/setobject.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Objects/setobject.c b/Objects/setobject.c
index 80101dda9beef8..82b58382081625 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -1744,8 +1744,10 @@ set_symmetric_difference(PySetObject *so, PyObject *other)
     if (otherset == NULL)
         return NULL;
     rv = set_symmetric_difference_update(otherset, (PyObject *)so);
-    if (rv == NULL)
+    if (rv == NULL) {
+        Py_DECREF(otherset);
         return NULL;
+    }
     Py_DECREF(rv);
     return (PyObject *)otherset;
 }

From 0fa374343a189c7dfb417de86c3c7eb112ebe3d8 Mon Sep 17 00:00:00 2001
From: Malek <lekmalek@gmail.com>
Date: Wed, 2 May 2018 09:44:51 +0200
Subject: [PATCH 2/2] NEWS.d entry for bpo-33391

---
 .../Core and Builtins/2018-05-02-08-36-03.bpo-33391.z4a7rb.rst   | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2018-05-02-08-36-03.bpo-33391.z4a7rb.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-05-02-08-36-03.bpo-33391.z4a7rb.rst b/Misc/NEWS.d/next/Core and Builtins/2018-05-02-08-36-03.bpo-33391.z4a7rb.rst
new file mode 100644
index 00000000000000..ab17aa408c06fe
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-05-02-08-36-03.bpo-33391.z4a7rb.rst	
@@ -0,0 +1 @@
+Fix a leak in set_symmetric_difference().