Python compatibility issues on current dev

[Maju-Ketchup]

Since the current dev is 'upgraded' to Python 3, working with Python 2 throws some errors because the 'ConfigParser' class was renamed to 'configparser'.
I have found a small work around to make it backwards compatible while changing one line in one file.

File: compatibility xpcc/scons/site_tools/configfile.py
old code(line 32):
import configparser
new code:

try:
       import configparser
except:
       import ConfigParser as configparser 

Should I commit this small to the current dev for backwards compatibility or should it stay the way it is so everyone should force update to Python 3?

[salkinium]

cc @daniel-k @mhthies @strongly-typed

[mhthies]

In theory, the build system should work with both, Python 2 and 3 resp. SCons 2.5 and 3.0. I also tested both Python and SCons versions on my computer, before submitting the changes for Python 3 compatibility. That makes me wondering, why the configparser import breaks on your system …

[rleh]

In Python 3, ConfigParser has been renamed to configparser for PEP 8 compliance. [↗]

import configparser should fail on all Python 2 installations.
I can reproduce this with Python 2 on my Fedora system:

$ python2
Python 2.7.13 (default, Dec  1 2017, 09:21:53) 
[GCC 6.4.1 20170727 (Red Hat 6.4.1-1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import configparser
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named configparser

[mhthies]

That lets @Maju-Ketchup's fix seem reasonable to me.

We could discuss if it's more elegant to check for the Python version, instead of catching the import's exception. However, as far as I remember, catching exceptions is "The Pythonic Way"™.

[chris-durand]

I also tested both Python and SCons versions on my computer, before submitting the changes for Python 3 compatibility. That makes me wondering, why the configparser import breaks on your system …

@mhthies You probably installed the python2 configparser backports package from pypi (https://pypi.python.org/pypi/configparser).

[rleh]

Python suggests the package six (Python 2 and 3 compatibility utilities), but this would add an additional dependency.
I like @Maju-Ketchup's solution too.