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

oscpache · oscpache · commit 936a405c86b5 · 2025-03-10T08:29:09.000-06:00
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
diff --git a/CHANGES.txt b/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
 ======
diff --git a/mysql-connector-python/src/mysql_capi.c b/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;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -3259,8 +3259,6 @@ void`
`3259`	`3259`	`MySQLPrepStmt_dealloc(MySQLPrepStmt *self)`
`3260`	`3260`	`{`
`3261`	`3261`	`if (self) {`
`3262`		`- MySQLPrepStmt_free_result(self);`
`3263`		`- MySQLPrepStmt_close(self);`
`3264`	`3262`	`Py_TYPE(self)->tp_free((PyObject *)self);`
`3265`	`3263`	`}`
`3266`	`3264`	`}`
`@@ -3951,6 +3949,10 @@ MySQLPrepStmt_close(MySQLPrepStmt *self)`
`3951`	`3949`	`return NULL;`
`3952`	`3950`	`}`
`3953`	`3951`
	`3952`	`+ // Decrementing the reference counting - counterpart of the`
	`3953`	`+ // increment taking place at MySQL_stmt_prepare.`
	`3954`	`+ Py_XDECREF(self);`
	`3955`	`+`
`3954`	`3956`	`Py_RETURN_NONE;`
`3955`	`3957`	`}`
`3956`	`3958`