According to the sphinx documentation, the .. autoattribute directive should be able to document instance attributes. However, if I do::

.. currentmodule:: xml.etree.ElementTree.. autoclass:: ElementTree.. autoattribute:: ElementTree._root

Then when building I get an AttributeError:

Traceback (most recent call last):etree.ElementTree.ElementTree                 File "/Volumes/Raptor/Library/Python/2.7/lib/python/site-packages/sphinx/ext/autodoc.py", line 326, in import_objectobj = self.get_attr(obj, part)File "/Volumes/Raptor/Library/Python/2.7/lib/python/site-packages/sphinx/ext/autodoc.py", line 232, in get_attrreturn safe_getattr(obj, name, *defargs)File "/Volumes/Raptor/Library/Python/2.7/lib/python/site-packages/sphinx/util/inspect.py", line 70, in safe_getattrraise AttributeError(name)
AttributeError: _root

even though if I instantiate ElementTree and try and access the _root attribute, it works fine::

>>> from xml.etree.ElementTree import ElementTree
>>> e = ElementTree()
>>> hasattr(e, '_root')
True

What am I doing wrong?

(I'm actually having this issue with one of my own classes, but am just using the ElementTree class as an example since it's in the standard library)

This looks like a bug in the way non-public instance attributes are handled. Sphinx is supposed to be able to recognize instance attributes defined in __init__.

I can't say how this should be fixed. There is an open bug report that seems to be related: Non-public instance attributes are not documented without __slots__.

If the following line is added to the definition of the ElementTree class in ElementTree.py,

__slots__  = ["_root"]

then the AttributeError that you get goes away.