[Python-checkins] bpo-44232: Fix type_new() error reporting (GH-26359)
vstinner
webhook-mailer at python.org
Tue May 25 16:28:21 EDT 2021
https://github.com/python/cpython/commit/bd199e72fb60a8ff001a023f23925092a290be91
commit: bd199e72fb60a8ff001a023f23925092a290be91
branch: main
author: Victor Stinner <vstinner at python.org>
committer: vstinner <vstinner at python.org>
date: 2021-05-25T22:28:10+02:00
summary:
bpo-44232: Fix type_new() error reporting (GH-26359)
Fix a regression in type() when a metaclass raises an exception. The
C function type_new() must properly report the exception when a
metaclass constructor raises an exception and the winner class is not
the metaclass.
files:
A Misc/NEWS.d/next/Core and Builtins/2021-05-25-18-20-10.bpo-44232.DMcCCf.rst
M Lib/test/test_types.py
M Objects/typeobject.c
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 25ebec5fa5509..767c3d06a4f58 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -1334,6 +1334,24 @@ class N(type, metaclass=M):
N(5)
self.assertEqual(str(cm.exception), expected_message)
+ def test_metaclass_new_error(self):
+ # bpo-44232: The C function type_new() must properly report the
+ # exception when a metaclass constructor raises an exception and the
+ # winner class is not the metaclass.
+ class ModelBase(type):
+ def __new__(cls, name, bases, attrs):
+ super_new = super().__new__
+ new_class = super_new(cls, name, bases, {})
+ if name != "Model":
+ raise RuntimeWarning(f"{name=}")
+ return new_class
+
+ class Model(metaclass=ModelBase):
+ pass
+
+ with self.assertRaises(RuntimeWarning):
+ type("SouthPonies", (Model,), {})
+
class SimpleNamespaceTests(unittest.TestCase):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-05-25-18-20-10.bpo-44232.DMcCCf.rst b/Misc/NEWS.d/next/Core and Builtins/2021-05-25-18-20-10.bpo-44232.DMcCCf.rst
new file mode 100644
index 0000000000000..fcd124d51442a
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2021-05-25-18-20-10.bpo-44232.DMcCCf.rst
@@ -0,0 +1,4 @@
+Fix a regression in :func:`type` when a metaclass raises an exception. The C
+function :c:func:`type_new` must properly report the exception when a metaclass
+constructor raises an exception and the winner class is not the metaclass.
+Patch by Victor Stinner.
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index af99ab79d14ad..14600855de8bb 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -3256,6 +3256,9 @@ type_new_get_bases(type_new_ctx *ctx, PyObject **type)
if (winner->tp_new != type_new) {
/* Pass it to the winner */
*type = winner->tp_new(winner, ctx->args, ctx->kwds);
+ if (*type == NULL) {
+ return -1;
+ }
return 1;
}
@@ -3307,6 +3310,7 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
PyObject *type = NULL;
int res = type_new_get_bases(&ctx, &type);
if (res < 0) {
+ assert(PyErr_Occurred());
return NULL;
}
if (res == 1) {
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