BUG#37399636: The C-extension has a memory leak when working with prepared statements

Fixed a memory leak in the C-extension occurring in
prepared statements. Prepared statement object
reference counting was being incremented upon
instantiation, but never decremented when closing
the statement.

Change-Id: Icbac790d47362a695f38666cecc79ad8cae1494b

Author: Oscar Pacheco

CHANGES.txt

@@ -18,6 +18,7 @@ v9.3.0
 - BUG#37453587: Github links in PyPI project's pages do not work
 - BUG#37447394: Unable to escape a parameter marker (`%s`) used in a query that should not be treated as a parameter marker
 - BUG#37418436: Arbitrary File Read in MySQL Python Client library
+- BUG#37399636: The C-extension has a memory leak when working with prepared statements
 
 v9.2.0
 ======

mysql-connector-python/src/mysql_capi.c

@@ -3259,8 +3259,6 @@ void
 MySQLPrepStmt_dealloc(MySQLPrepStmt *self)
 {
     if (self) {
-        MySQLPrepStmt_free_result(self);
-        MySQLPrepStmt_close(self);
         Py_TYPE(self)->tp_free((PyObject *)self);
     }
 }
@@ -3951,6 +3949,10 @@ MySQLPrepStmt_close(MySQLPrepStmt *self)
         return NULL;
     }
 
+    // Decrementing the reference counting - counterpart of the
+    // increment taking place at MySQL_stmt_prepare.
+    Py_XDECREF(self);
+
     Py_RETURN_NONE;
 }