There was a possibility that the initialization of _sqlite, when it failed,

brettcannon · brettcannon · commit e144507b0983 · 2011-02-04T20:24:02.000Z
would lead to a decref of a NULL. Fixes issue #11110.
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -15,6 +15,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #11110: Fix a potential decref of a NULL in sqlite3.
+
 - Issue #8275: Fix passing of callback arguments with ctypes under Win64.
   Patch by Stan Mihai.
 
diff --git a/Modules/_sqlite/module.c b/Modules/_sqlite/module.c
@@ -329,7 +329,7 @@ PyMODINIT_FUNC PyInit__sqlite3(void)
         (pysqlite_statement_setup_types() < 0) ||
         (pysqlite_prepare_protocol_setup_types() < 0)
        ) {
-        Py_DECREF(module);
+        Py_XDECREF(module);
         return NULL;
     }
 

Original file line number	Diff line number	Diff line change
`@@ -329,7 +329,7 @@ PyMODINIT_FUNC PyInit__sqlite3(void)`
`329`	`329`	`(pysqlite_statement_setup_types() < 0) \|\|`
`330`	`330`	`(pysqlite_prepare_protocol_setup_types() < 0)`
`331`	`331`	`) {`
`332`		`- Py_DECREF(module);`
	`332`	`+ Py_XDECREF(module);`
`333`	`333`	`return NULL;`
`334`	`334`	`}`
`335`	`335`