python · kumaraditya303 · Mar 27, 2026 · Mar 21, 2026 · Mar 21, 2026 · Mar 21, 2026
@@ -2561,6 +2561,30 @@ def test_incorrect_constructor(self):
        args = ("bad.py", 1, 2, "abcdefg", 1)
        self.assertRaises(TypeError, SyntaxError, "bad bad", args)

+    def test_syntax_error_memory_leak(self):
+        # gh-146250: memory leak with re-initialization of SyntaxError
+        e = SyntaxError("msg", ("file.py", 1, 2, "txt", 2, 3))
+        e.__init__("new_msg", ("new_file.py", 2, 3, "new_txt", 3, 4))
+        self.assertEqual(e.msg, "new_msg")
+        self.assertEqual(e.args, ("new_msg", ("new_file.py", 2, 3, "new_txt", 3, 4)))
+        self.assertEqual(e.filename, "new_file.py")
+        self.assertEqual(e.lineno, 2)
+        self.assertEqual(e.offset, 3)
+        self.assertEqual(e.text, "new_txt")
+        self.assertEqual(e.end_lineno, 3)
+        self.assertEqual(e.end_offset, 4)
+
+        e = SyntaxError("msg", ("file.py", 1, 2, "txt", 2, 3))
+        e.__init__("new_msg", ("new_file.py", 2, 3, "new_txt"))
+        self.assertEqual(e.msg, "new_msg")
+        self.assertEqual(e.args, ("new_msg", ("new_file.py", 2, 3, "new_txt")))
+        self.assertEqual(e.filename, "new_file.py")
+        self.assertEqual(e.lineno, 2)
+        self.assertEqual(e.offset, 3)
+        self.assertEqual(e.text, "new_txt")
+        self.assertIsNone(e.end_lineno)
+        self.assertIsNone(e.end_offset)
+

 class TestInvalidExceptionMatcher(unittest.TestCase):
    def test_except_star_invalid_exception_type(self):

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-03-21-11-55-16.gh-issue-146250.ahl3O2.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-21-11-55-16.gh-issue-146250.ahl3O2.rst
@@ -0,0 +1 @@
+Fixed a memory leak in :exc:`SyntaxError` when re-initializing it.
@@ -2802,23 +2802,25 @@ SyntaxError_init(PyObject *op, PyObject *args, PyObject *kwds)
            return -1;
        }

-        self->end_lineno = NULL;
-        self->end_offset = NULL;
+        PyObject *filename, *lineno, *offset, *text;
+        PyObject *end_lineno = NULL;
+        PyObject *end_offset = NULL;
+        PyObject *metadata = NULL;
        if (!PyArg_ParseTuple(info, "OOOO|OOO",
-                              &self->filename, &self->lineno,
-                              &self->offset, &self->text,
-                              &self->end_lineno, &self->end_offset, &self->metadata)) {
+                              &filename, &lineno,
+                              &offset, &text,
+                              &end_lineno, &end_offset, &metadata)) {
            Py_DECREF(info);
            return -1;
        }

-        Py_INCREF(self->filename);
-        Py_INCREF(self->lineno);
-        Py_INCREF(self->offset);
-        Py_INCREF(self->text);
-        Py_XINCREF(self->end_lineno);
-        Py_XINCREF(self->end_offset);
-        Py_XINCREF(self->metadata);
+        Py_XSETREF(self->filename, Py_NewRef(filename));
+        Py_XSETREF(self->lineno, Py_NewRef(lineno));
+        Py_XSETREF(self->offset, Py_NewRef(offset));
+        Py_XSETREF(self->text, Py_NewRef(text));
+        Py_XSETREF(self->end_lineno, Py_XNewRef(end_lineno));
+        Py_XSETREF(self->end_offset, Py_XNewRef(end_offset));
+        Py_XSETREF(self->metadata, Py_XNewRef(metadata));
        Py_DECREF(info);

        if (self->end_lineno != NULL && self->end_offset == NULL) {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Fixed a memory leak in :exc:`SyntaxError` when re-initializing it.