Duplicate output on Python tab completion (OsX 10.8)

Question

Using the snippet below, I have added tab completion to the python interpreter.

import readline
import rlcompleter
if 'libedit' in readline.__doc__:
    readline.parse_and_bind("bind ^I rl_complete")
else:
    readline.parse_and_bind("tab: complete")

However, I have encountered a weird behaviour where after hitting TAB, the interpreter would give duplicates as such:

Python 2.7.3 (v2.7.3:70274d53c1dd, Apr  9 2012, 20:52:43)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> d=dict()
>>> d.
Display all 108 possibilities? (y or n)
d.__class__(         d.__class__(         d.__class__(
d.__class__(         d.__cmp__(           d.__cmp__(
d.__contains__(      d.__contains__(      d.__delattr__(
d.__delattr__(       d.__delattr__(       d.__delitem__(
d.__delitem__(       d.__doc__            d.__doc__
d.__doc__            d.__eq__(            d.__eq__(
d.__format__(        d.__format__(        d.__format__(
d.__ge__(            d.__ge__(            d.__getattribute__(
d.__getattribute__(  d.__getattribute__(  d.__getitem__(
d.__getitem__(       d.__gt__(            d.__gt__(
d.__hash__           d.__hash__           d.__hash__
d.__init__(          d.__init__(          d.__init__(
d.__iter__(          d.__iter__(          d.__le__(
d.__le__(            d.__len__(           d.__len__(
d.__lt__(            d.__lt__(            d.__ne__(
d.__ne__(            d.__new__(           d.__new__(
d.__new__(           d.__reduce__(        d.__reduce__(
d.__reduce__(        d.__reduce_ex__(     d.__reduce_ex__(
d.__reduce_ex__(     d.__repr__(          d.__repr__(
d.__repr__(          d.__setattr__(       d.__setattr__(
d.__setattr__(       d.__setitem__(       d.__setitem__(
d.__sizeof__(        d.__sizeof__(        d.__sizeof__(
d.__str__(           d.__str__(           d.__str__(
d.__subclasshook__(  d.__subclasshook__(  d.__subclasshook__(
d.clear(             d.clear(             d.copy(
d.copy(              d.fromkeys(          d.fromkeys(
d.get(               d.get(               d.has_key(
d.has_key(           d.items(             d.items(
d.iteritems(         d.iteritems(         d.iterkeys(
d.iterkeys(          d.itervalues(        d.itervalues(
d.keys(              d.keys(              d.pop(
d.pop(               d.popitem(           d.popitem(
d.setdefault(        d.setdefault(        d.update(
d.update(            d.values(            d.values(
d.viewitems(         d.viewitems(         d.viewkeys(
d.viewkeys(          d.viewvalues(        d.viewvalues(

108 possibilities! min 2, max 4 duplicates.

Furthermore,

• if I subclass dict the total number of possibilities increases to 160 (and then to 209, 258).
• if I type enough characters for TAB to nail the command, it does so without displaying duplicates.

Any pointers or debugging tips are appreciated.

Answer 1

I have solved this issue by adding a custom completer. It now works as expected.

import readline
import rlcompleter

c = rlcompleter.Completer()

def complete(text, state):
    buffer = readline.get_line_buffer()
    first = c.complete(buffer, 0)
    if state == 0:
        return first
    current = c.complete(buffer, state)
    if current != first:
        return current

readline.parse_and_bind('bind ^I rl_complete')
readline.set_completer(complete)