How can I fix this Python script?

Question

I'm trying to convert a CVS repository to Git using cvs2svn and am following the directions on this page. I got to step 7 but am getting an error running git-move-refs.py:

Traceback (most recent call last):
  File "../../cvs2svn-trunk/contrib/git-move-refs.py", line 23, in ?
    from subprocess import Popen, PIPE, call
ImportError: No module named subprocess

For reference, this is what the script shows:

usage = 'USAGE: %prog [options]'

import sys
import optparse
from subprocess import Popen, PIPE, call

I'm not a Python expert but from browsing the web it looks like subprocess is a standard module, right? I'm using a Python installation built from source for version 2.6.3. What am I missing for this script to work?

`subprocess` was introduced in Python 2.4. How did you compile this Python package? — Blender, Oct 12 '12 at 19:53
Are you *certain* that you're running the 2.6.3 you compiled, and not a much older one that's already installed somewhere else? — Greg Hewgill, Oct 12 '12 at 19:54
[prompt] python Python 2.6.3 (r263:75183, Oct 12 2009, 19:59:05) [GCC 3.4.6 20060404 (Red Hat 3.4.6-9)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import subprocess >>> — dromodel, Oct 12 '12 at 20:02
@balor123: What's the output of `/usr/bin/python --version`? — Mechanical snail, Oct 12 '12 at 20:19
Doesn't the script have some kind of shebang? (the `#!` line) Most likely it's using `/usr/bin/python` and you have installed yours as `/usr/local/bin/python`. — Michał Górny, Oct 12 '12 at 20:23

score 2 · Accepted Answer · answered Oct 12 '12 at 20:25

I'm guessing that you have an old version (pre-2.4) of Python at /usr/bin/python, from your distribution, and the Python 2.6 you compiled is somewhere else (like /usr/local/bin/python). You have the Python 2.6 executable on your path before /usr/bin, so when you execute python from the command-line you get Python 2.6.

However, looking at the cvs2svn source code, git-move-refs.py's interpreter line is hard-coded to

#!/usr/bin/python

instead of #!/usr/bin/env python, which means when you run the script it uses the old Python.

As a workaround, run the script by passing it to your Python 2.6 interpreter:

user@host$ python /path/to/cvs2svn/contrib/git-move-refs.py

…or replace the shebang in the script. I doubt the script is called directly. — Michał Górny, Oct 12 '12 at 20:26
@MichałGórny: Step 7 in the instructions says to run that script, so the asker probably is calling it directly. — Mechanical snail, Oct 12 '12 at 20:27

How can I fix this Python script?

1 Answers1