python
diff --git a/‎Lib/test/test_raise.py‎
Lines changed: 7 additions & 11 deletions b/‎Lib/test/test_raise.py‎
Lines changed: 7 additions & 11 deletions
diff --git a/‎Misc/NEWS.d/next/Core_and_Builtins/2025-11-02-12-47-38.gh-issue-140530.S934bp.rst‎
Lines changed: 2 additions & 0 deletions b/‎Misc/NEWS.d/next/Core_and_Builtins/2025-11-02-12-47-38.gh-issue-140530.S934bp.rst‎
Lines changed: 2 additions & 0 deletions
diff --git a/‎Python/ceval.c‎
Lines changed: 1 addition & 0 deletions b/‎Python/ceval.c‎
Lines changed: 1 addition & 0 deletions
@@ -186,18 +186,14 @@ def test_class_cause(self):
             self.fail("No exception raised")
 
     def test_class_cause_nonexception_result(self):
-        class ConstructsNone(BaseException):
-            @classmethod
+        # See https://github.com/python/cpython/issues/140530.
+        class ConstructMortal(BaseException):
             def __new__(*args, **kwargs):
-                return None
-        try:
-            raise IndexError from ConstructsNone
-        except TypeError as e:
-            self.assertIn("should have returned an instance of BaseException", str(e))
-        except IndexError:
-            self.fail("Wrong kind of exception raised")
-        else:
-            self.fail("No exception raised")
+                return ["mortal value"]
+
+        msg = ".*should have returned an instance of BaseException.*"
+        with self.assertRaisesRegex(TypeError, msg):
+            raise IndexError from ConstructMortal
 
     def test_instance_cause(self):
         cause = KeyError()
 
@@ -0,0 +1,2 @@
+Fix a reference leak when ``raise exc from cause`` fails. Patch by Bénédikt
+Tran.
@@ -2148,6 +2148,7 @@ do_raise(PyThreadState *tstate, PyObject *exc, PyObject *cause)
                               "calling %R should have returned an instance of "
                               "BaseException, not %R",
                               cause, Py_TYPE(fixed_cause));
+                Py_DECREF(fixed_cause);
                 goto raise_error;
             }
             Py_DECREF(cause);
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Fix a reference leak when ``raise exc from cause`` fails. Patch by Bénédikt
	`2`	`+Tran.`
Original file line number	Diff line number	Diff line change
`@@ -2148,6 +2148,7 @@ do_raise(PyThreadState tstate, PyObject exc, PyObject *cause)`
`2148`	`2148`	`"calling %R should have returned an instance of "`
`2149`	`2149`	`"BaseException, not %R",`
`2150`	`2150`	`cause, Py_TYPE(fixed_cause));`
	`2151`	`+ Py_DECREF(fixed_cause);`
`2151`	`2152`	`goto raise_error;`
`2152`	`2153`	`}`
`2153`	`2154`	`Py_DECREF(cause);`