./python completion problems

[Barry Warsaw]

Binary package hint: bash-completion

Get a source checkout of Python:

bzr branch lp:python
cd python
./configure && make
./python Lib/test[TAB]

The following error occurs at the TAB

% ./python Lib/testbash: COMP_WORDS: bad array subscript

[Jacob Wan (wildlemur)]

I noticed this problem too. One bit of information to add: it seems to only happen when the python executable is being invoked via a symbolic link. For example, if I want to run the script app.py in the current directory, "/usr/bin/python a<TAB>" causes the error, while "/usr/bin/python2.6 a<TAB>" does not. In either case, the correct thing ultimately happens, but the symlink version inserts the "COMP_WORDS: bad array subscript" message.

[Michael Foord (mfoord)]

I have this problem when trying to use bash completion with a buildout python.

The following is sufficient to trigger it:

    bin/python <tab>

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Nicolas Krzywinski (nsk7even)]

I just encountered this on my server, which is debian with bash 4.1.5(1)-release, python 2.6.6 and kernel 2.6.32-5-amd64

But it works with calling the python cmd only:
python /etc/ba<TAB>sh_completion.d/

Exploit:
/usr/bin/python /etc/ba<TAB>-bash: COMP_WORDS: Falscher Feldbezeichner.
sh

Notice: it does not matter what the path is

Since this is the only bug I found for this (german spelled) error message, I am posting here, though I encountered it NOT on Ubuntu, but Debian.

[Peter Cordes (peter-cordes)]

Can anyone else confirm that /usr/bin/python /etc/ba<TAB> is a valid testcase for this? Or is ln -s /usr/bin/python tmp/python needed?

 I'm not seeing a problem on trusty with Nicolas's testcase, but I don't have anything special with python source lying around.

[Peter Cordes (peter-cordes)]

There's something fishy going on,

/usr/bin/python /etc/ba[TAB] => prints a single completion, but doesn't apply it.
bash_completion.d/

python /etc/ba[TAB] => /etc/bash_completion.d/

 I think when testing this before, I had my completion dynamic loading messed up, and wasn't getting /usr/share/bash-completion/completions/python

Turns out keeping an unmodified copy of what Ubuntu ships isn't enough, you need a symlink to /usr/share/bash-completion/completions in the directory with it, because it cares about where it lives. Checking other bugs I closed recently in case I tested improperly... xD