Example:

>>> completer = rlcompleter.Completer()

>>> class A(object):
...     def foo(): pass
...     def foobar(): pass

>>> completer.complete("A.foo(", 0)
'A.foo('
>>> completer.complete("A.foo(", 1)
'A.foobar('

I consider the last match a bug.

The root of this bug is that in attr_matches the regular expression ignores any trailing non-alphanumeric characters by using the "\w" sequence. Note that it would also match "A.foo?%&@" to both "A.foo" and "A.foobar".

I propose this regex instead:
r"(\w+(\.\w+)*)\.([^.]*)"
What do people think?