diff options
| -rw-r--r-- | Lib/test/test_typing.py | 77 | ||||
| -rw-r--r-- | Lib/typing.py | 21 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2023-11-09-11-07-34.gh-issue-111874.dzYc3j.rst | 4 |
3 files changed, 99 insertions, 3 deletions
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index 31d7fda..6698031 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -7535,6 +7535,83 @@ class NamedTupleTests(BaseTestCase): self.assertEqual(CallNamedTuple.__orig_bases__, (NamedTuple,)) + def test_setname_called_on_values_in_class_dictionary(self): + class Vanilla: + def __set_name__(self, owner, name): + self.name = name + + class Foo(NamedTuple): + attr = Vanilla() + + foo = Foo() + self.assertEqual(len(foo), 0) + self.assertNotIn('attr', Foo._fields) + self.assertIsInstance(foo.attr, Vanilla) + self.assertEqual(foo.attr.name, "attr") + + class Bar(NamedTuple): + attr: Vanilla = Vanilla() + + bar = Bar() + self.assertEqual(len(bar), 1) + self.assertIn('attr', Bar._fields) + self.assertIsInstance(bar.attr, Vanilla) + self.assertEqual(bar.attr.name, "attr") + + def test_setname_raises_the_same_as_on_other_classes(self): + class CustomException(BaseException): pass + + class Annoying: + def __set_name__(self, owner, name): + raise CustomException + + annoying = Annoying() + + with self.assertRaises(CustomException) as cm: + class NormalClass: + attr = annoying + normal_exception = cm.exception + + with self.assertRaises(CustomException) as cm: + class NamedTupleClass(NamedTuple): + attr = annoying + namedtuple_exception = cm.exception + + self.assertIs(type(namedtuple_exception), CustomException) + self.assertIs(type(namedtuple_exception), type(normal_exception)) + + self.assertEqual(len(namedtuple_exception.__notes__), 1) + self.assertEqual( + len(namedtuple_exception.__notes__), len(normal_exception.__notes__) + ) + + expected_note = ( + "Error calling __set_name__ on 'Annoying' instance " + "'attr' in 'NamedTupleClass'" + ) + self.assertEqual(namedtuple_exception.__notes__[0], expected_note) + self.assertEqual( + namedtuple_exception.__notes__[0], + normal_exception.__notes__[0].replace("NormalClass", "NamedTupleClass") + ) + + def test_strange_errors_when_accessing_set_name_itself(self): + class CustomException(Exception): pass + + class Meta(type): + def __getattribute__(self, attr): + if attr == "__set_name__": + raise CustomException + return object.__getattribute__(self, attr) + + class VeryAnnoying(metaclass=Meta): pass + + very_annoying = VeryAnnoying() + + with self.assertRaises(CustomException): + class Foo(NamedTuple): + attr = very_annoying + class TypedDictTests(BaseTestCase): def test_basics_functional_syntax(self): diff --git a/Lib/typing.py b/Lib/typing.py index 872aca8..216f0c1 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -2743,11 +2743,26 @@ class NamedTupleMeta(type): class_getitem = _generic_class_getitem nm_tpl.__class_getitem__ = classmethod(class_getitem) # update from user namespace without overriding special namedtuple attributes - for key in ns: + for key, val in ns.items(): if key in _prohibited: raise AttributeError("Cannot overwrite NamedTuple attribute " + key) - elif key not in _special and key not in nm_tpl._fields: - setattr(nm_tpl, key, ns[key]) + elif key not in _special: + if key not in nm_tpl._fields: + setattr(nm_tpl, key, val) + try: + set_name = type(val).__set_name__ + except AttributeError: + pass + else: + try: + set_name(val, nm_tpl, key) + except BaseException as e: + e.add_note( + f"Error calling __set_name__ on {type(val).__name__!r} " + f"instance {key!r} in {typename!r}" + ) + raise + if Generic in bases: nm_tpl.__init_subclass__() return nm_tpl diff --git a/Misc/NEWS.d/next/Library/2023-11-09-11-07-34.gh-issue-111874.dzYc3j.rst b/Misc/NEWS.d/next/Library/2023-11-09-11-07-34.gh-issue-111874.dzYc3j.rst new file mode 100644 index 0000000..5040820 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-11-09-11-07-34.gh-issue-111874.dzYc3j.rst @@ -0,0 +1,4 @@ +When creating a :class:`typing.NamedTuple` class, ensure +:func:`~object.__set_name__` is called on all objects that define +``__set_name__`` and exist in the values of the ``NamedTuple`` class's class +dictionary. Patch by Alex Waygood. |