diff options
| author | Petr Viktorin <encukou@gmail.com> | 2022-11-07 18:45:50 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-11-07 18:45:50 (GMT) |
| commit | 1438b779971605e516bd0a4051a704d6ffbbd58d (patch) | |
| tree | 578698b69d07e4f6877af41a9557f9c0cc12251b | |
| parent | 4a1c58d504a49eeb9be7beef3ca861a9d6b28ede (diff) | |
| download | cpython-1438b779971605e516bd0a4051a704d6ffbbd58d.zip cpython-1438b779971605e516bd0a4051a704d6ffbbd58d.tar.gz cpython-1438b779971605e516bd0a4051a704d6ffbbd58d.tar.bz2 | |
gh-96746: Docs: Clear up Py_TPFLAGS_DISALLOW_INSTANTIATION inheritance (GH-99002)
The flag is not inherited, but its effect -- a NULL tp_new -- is.
Drop hints for people who come here wanting to “disallow instantiation”.
| -rw-r--r-- | Doc/c-api/typeobj.rst | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Doc/c-api/typeobj.rst b/Doc/c-api/typeobj.rst index 8ccdece..4c462f4 100644 --- a/Doc/c-api/typeobj.rst +++ b/Doc/c-api/typeobj.rst @@ -1245,6 +1245,17 @@ and :c:type:`PyType_Type` effectively act as defaults.) **Inheritance:** This flag is not inherited. + However, subclasses will not be instantiable unless they provide a + non-NULL :c:member:`~PyTypeObject.tp_new` (which is only possible + via the C API). + + .. note:: + + To disallow instantiating a class directly but allow instantiating + its subclasses (e.g. for an :term:`abstract base class`), + do not use this flag. + Instead, make :c:member:`~PyTypeObject.tp_new` only succeed for + subclasses. .. versionadded:: 3.10 |