https://github.com/python/cpython/commit/09f235e614ebed053ef22d90782154f66763a6a9 commit: 09f235e614ebed053ef22d90782154f66763a6a9 branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: zware <[email protected]> date: 2026-07-18T08:32:04-05:00 summary:
[3.13] gh-122102: Fix/improve docs of descriptor-related tools in `inspect` (GH-153950) (cherry picked from commit 87f8fc8e00704396a0c598c8843cdde373c0ea4c) Co-authored-by: Jan Kaliszewski <[email protected]> Co-authored-by: Bénédikt Tran <[email protected]> files: M Doc/library/inspect.rst M Lib/inspect.py diff --git a/Doc/library/inspect.rst b/Doc/library/inspect.rst index 3e0df312f1c8fe..9ebed6ca888a80 100644 --- a/Doc/library/inspect.rst +++ b/Doc/library/inspect.rst @@ -538,8 +538,7 @@ attributes (see :ref:`import-mod-attrs` for module attributes): .. function:: ismethoddescriptor(object) Return ``True`` if the object is a method descriptor, but not if - :func:`ismethod`, :func:`isclass`, :func:`isfunction` or :func:`isbuiltin` - are true. + :func:`isclass`, :func:`ismethod` or :func:`isfunction` is true. This, for example, is true of ``int.__add__``. An object passing this test has a :meth:`~object.__get__` method, but not a :meth:`~object.__set__` @@ -547,10 +546,10 @@ attributes (see :ref:`import-mod-attrs` for module attributes): attributes varies. A :attr:`~definition.__name__` attribute is usually sensible, and :attr:`~definition.__doc__` often is. - Methods implemented via descriptors that also pass one of the other tests - return ``False`` from the :func:`ismethoddescriptor` test, simply because the - other tests promise more -- you can, e.g., count on having the - :attr:`~method.__func__` attribute (etc) when an object passes + Method descriptors that also pass any of the other tests (:func:`!isclass`, + :func:`!ismethod` or :func:`!isfunction`) make this function return ``False``, + simply because those other tests promise more -- you can, for example, count + on having the :attr:`~method.__func__` attribute when an object passes :func:`ismethod`. .. versionchanged:: 3.13 @@ -561,16 +560,28 @@ attributes (see :ref:`import-mod-attrs` for module attributes): .. function:: isdatadescriptor(object) - Return ``True`` if the object is a data descriptor. + Return ``True`` if the object is a data descriptor, but not if + :func:`isclass`, :func:`ismethod` or :func:`isfunction` is true. - Data descriptors have a :attr:`~object.__set__` or a :attr:`~object.__delete__` method. - Examples are properties (defined in Python), getsets, and members. The - latter two are defined in C and there are more specific tests available for - those types, which is robust across Python implementations. Typically, data - descriptors will also have :attr:`~definition.__name__` and :attr:`!__doc__` attributes - (properties, getsets, and members have both of these attributes), but this is - not guaranteed. + Data descriptors always have a :meth:`~object.__set__` method and/or + a :meth:`~object.__delete__` method. Optionally, they may also have a + :meth:`~object.__get__` method. + Examples of data descriptors are :func:`properties <property>`, getsets and + member descriptors. Note that for the latter two (defined only in C extension + modules), more specific tests are available: :func:`isgetsetdescriptor` and + :func:`ismemberdescriptor`, respectively. + + While data descriptors may also have :attr:`~definition.__name__` and + :attr:`!__doc__` attributes (as properties, getsets and member descriptors + do), this is not necessarily the case in general. + + .. versionchanged:: 3.8 + This function now reports objects with only a :meth:`~object.__set__` method + as being data descriptors (the presence of :meth:`~object.__get__` is no + longer required for that). Moreover, objects with :meth:`~object.__delete__`, + but not :meth:`~object.__set__`, are now properly recognized as data + descriptors as well, which was not the case previously. .. function:: isgetsetdescriptor(object) diff --git a/Lib/inspect.py b/Lib/inspect.py index ea384ba5b53bb2..f8db5bdb7958ec 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -312,18 +312,18 @@ def ismethod(object): def ismethoddescriptor(object): """Return true if the object is a method descriptor. - But not if ismethod() or isclass() or isfunction() are true. + But not if ismethod(), isclass() or isfunction() is true. - This is new in Python 2.2, and, for example, is true of int.__add__. - An object passing this test has a __get__ attribute, but not a - __set__ attribute or a __delete__ attribute. Beyond that, the set - of attributes varies; __name__ is usually sensible, and __doc__ - often is. + An object passing this test (for example, int.__add__) has a __get__ + attribute, but not a __set__ attribute or a __delete__ attribute. + Beyond that, the set of attributes varies; __name__ is usually + sensible, and __doc__ often is. Methods implemented via descriptors that also pass one of the other - tests return false from the ismethoddescriptor() test, simply because - the other tests promise more -- you can, e.g., count on having the - __func__ attribute (etc) when an object passes ismethod().""" + tests (ismethod(), isclass(), isfunction()) make this function return + false, simply because those other tests promise more -- you can, for + example, count on having the __func__ attribute when an object passes + ismethod().""" if isclass(object) or ismethod(object) or isfunction(object): # mutual exclusion return False @@ -340,8 +340,13 @@ def ismethoddescriptor(object): def isdatadescriptor(object): """Return true if the object is a data descriptor. + But not if ismethod(), isclass() or isfunction() is true. + Data descriptors have a __set__ or a __delete__ attribute. Examples are - properties (defined in Python) and getsets and members (defined in C). + properties, getsets, and members. For the latter two (defined only in C + extension modules) more specific tests are available as well: + isgetsetdescriptor() and ismemberdescriptor(), respectively. + Typically, data descriptors will also have __name__ and __doc__ attributes (properties, getsets, and members have both of these attributes), but this is not guaranteed.""" _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
