bpo-40737: Fix possible reference leak for sqlite3 initialization (GH-20323)

Author: Erlend Egeberg Aasland

Misc/NEWS.d/next/Library/2020-05-23-00-22-11.bpo-40737.iph-CM.rst

@@ -0,0 +1 @@
+Fix possible reference leak for :mod:`sqlite3` initialization.

Modules/_sqlite/module.c

@@ -346,6 +346,14 @@ static struct PyModuleDef _sqlite3module = {
         NULL
 };
 
+#define ADD_TYPE(module, type)                 \
+do {                                           \
+    if (PyModule_AddType(module, &type) < 0) { \
+        Py_DECREF(module);                     \
+        return NULL;                           \
+    }                                          \
+} while (0)
+
 PyMODINIT_FUNC PyInit__sqlite3(void)
 {
     PyObject *module, *dict;
@@ -366,14 +374,10 @@ PyMODINIT_FUNC PyInit__sqlite3(void)
         return NULL;
     }
 
-    Py_INCREF(&pysqlite_ConnectionType);
-    PyModule_AddObject(module, "Connection", (PyObject*) &pysqlite_ConnectionType);
-    Py_INCREF(&pysqlite_CursorType);
-    PyModule_AddObject(module, "Cursor", (PyObject*) &pysqlite_CursorType);
-    Py_INCREF(&pysqlite_PrepareProtocolType);
-    PyModule_AddObject(module, "PrepareProtocol", (PyObject*) &pysqlite_PrepareProtocolType);
-    Py_INCREF(&pysqlite_RowType);
-    PyModule_AddObject(module, "Row", (PyObject*) &pysqlite_RowType);
+    ADD_TYPE(module, pysqlite_ConnectionType);
+    ADD_TYPE(module, pysqlite_CursorType);
+    ADD_TYPE(module, pysqlite_PrepareProtocolType);
+    ADD_TYPE(module, pysqlite_RowType);
 
     if (!(dict = PyModule_GetDict(module))) {
         goto error;