diff options
| -rw-r--r-- | Doc/library/functions.rst | 7 | ||||
| -rw-r--r-- | Lib/test/test_super.py | 27 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2023-12-20-08-54-54.gh-issue-113212.62AUlw.rst | 1 | ||||
| -rw-r--r-- | Objects/typeobject.c | 19 |
4 files changed, 51 insertions, 3 deletions
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index c731b6f..4682ec9 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -1800,6 +1800,13 @@ are always available. They are listed here in alphabetical order. the second argument is a type, ``issubclass(type2, type)`` must be true (this is useful for classmethods). + When called directly within an ordinary method of a class, both arguments may + be omitted ("zero-argument :func:`!super`"). In this case, *type* will be the + enclosing class, and *obj* will be the first argument of the immediately + enclosing function (typically ``self``). (This means that zero-argument + :func:`!super` will not work as expected within nested functions, including + generator expressions, which implicitly create nested functions.) + There are two typical use cases for *super*. In a class hierarchy with single inheritance, *super* can be used to refer to parent classes without naming them explicitly, thus making the code more maintainable. This use diff --git a/Lib/test/test_super.py b/Lib/test/test_super.py index 43162c5..f8e968b 100644 --- a/Lib/test/test_super.py +++ b/Lib/test/test_super.py @@ -396,6 +396,33 @@ class TestSuper(unittest.TestCase): with self.assertRaisesRegex(TypeError, "argument 1 must be a type"): C().method() + def test_supercheck_fail(self): + class C: + def method(self, type_, obj): + return super(type_, obj).method() + + c = C() + err_msg = ( + r"super\(type, obj\): obj \({} {}\) is not " + r"an instance or subtype of type \({}\)." + ) + + cases = ( + (int, c, int.__name__, C.__name__, "instance of"), + # obj is instance of type + (C, list(), C.__name__, list.__name__, "instance of"), + # obj is type itself + (C, list, C.__name__, list.__name__, "type"), + ) + + for case in cases: + with self.subTest(case=case): + type_, obj, type_str, obj_str, instance_or_type = case + regex = err_msg.format(instance_or_type, obj_str, type_str) + + with self.assertRaisesRegex(TypeError, regex): + c.method(type_, obj) + def test_super___class__(self): class C: def method(self): diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-12-20-08-54-54.gh-issue-113212.62AUlw.rst b/Misc/NEWS.d/next/Core and Builtins/2023-12-20-08-54-54.gh-issue-113212.62AUlw.rst new file mode 100644 index 0000000..6edbc9c --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2023-12-20-08-54-54.gh-issue-113212.62AUlw.rst @@ -0,0 +1 @@ +Improve :py:class:`super` error messages. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 5261ef9..ea29a38 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -10404,9 +10404,22 @@ supercheck(PyTypeObject *type, PyObject *obj) Py_XDECREF(class_attr); } - PyErr_SetString(PyExc_TypeError, - "super(type, obj): " - "obj must be an instance or subtype of type"); + const char *type_or_instance, *obj_str; + + if (PyType_Check(obj)) { + type_or_instance = "type"; + obj_str = ((PyTypeObject*)obj)->tp_name; + } + else { + type_or_instance = "instance of"; + obj_str = Py_TYPE(obj)->tp_name; + } + + PyErr_Format(PyExc_TypeError, + "super(type, obj): obj (%s %.200s) is not " + "an instance or subtype of type (%.200s).", + type_or_instance, obj_str, type->tp_name); + return NULL; } |