[New-bugs-announce] [issue24766] Subclass of property doesn't preserve instance __doc__ when using doc= argument
report at bugs.python.org
Fri Jul 31 19:02:03 CEST 2015
New submission from Erik Bray:
This issue is directly related to http://bugs.python.org/issue5890, the solution to which I think was incomplete.
The examples below use a trivial subclass of property (but apply as well to a less trivial one):
>>> class myproperty(property): pass
When using myproperty with the decorator syntax, or simply without specifying a doc= argument, the docstring is properly inherited from the getter, as was fixed by issue5890:
>>> class A:
... def foo(self):
... """The foo."""
... return 1
However, when using the doc= argument, this behavior is broken:
>>> class B:
... def _get_foo(self): return 1
... foo = myproperty(_get_foo, doc="The foo.")
>>> B.foo.__doc__ is None
The attached patch resolves the issue by applying the special case for subclasses more generally. If this looks good I'll add a test as well.
One thing I went back and forth on in the "if (Py_TYPE(self) != &PyProperty_Type)" block was whether or not to then deref prop->prop_doc and set it to NULL, since I don't think it's needed anymore at this point. But I decided it was ultimately harmless to leave it.
components: Interpreter Core
title: Subclass of property doesn't preserve instance __doc__ when using doc= argument
Added file: http://bugs.python.org/file40086/property-doc.patch
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