[Python-checkins] bpo-40998: Fix a refleak in create_filter() (GH-23365)

[miss-islington]

https://github.com/python/cpython/commit/d1e38d4023aa29e7ed64d4f8eb9c1e4a3c86a2e5
commit: d1e38d4023aa29e7ed64d4f8eb9c1e4a3c86a2e5
branch: master
author: Victor Stinner <vstinner at python.org>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2020-11-18T06:57:10-08:00
summary:

bpo-40998: Fix a refleak in create_filter() (GH-23365)

files:
M Python/_warnings.c

diff --git a/Python/_warnings.c b/Python/_warnings.c
index 8d33fbe0f878b..313420c63148f 100644
--- a/Python/_warnings.c
+++ b/Python/_warnings.c
@@ -69,12 +69,14 @@ create_filter(PyObject *category, _Py_Identifier *id, const char *modname)
             return NULL;
         }
     } else {
-        modname_obj = Py_None;
+        modname_obj = Py_NewRef(Py_None);
     }
 
     /* This assumes the line number is zero for now. */
-    return PyTuple_Pack(5, action_str, Py_None,
-                        category, modname_obj, _PyLong_GetZero());
+    PyObject *filter = PyTuple_Pack(5, action_str, Py_None,
+                                    category, modname_obj, _PyLong_GetZero());
+    Py_DECREF(modname_obj);
+    return filter;
 }
 #endif