Local configuration files are ignored if parse_argv is False

[kynan]

When using pep8 as a library, there is currently no way to make the StyleGuide read local configuration files (tox.ini, setup.cfg) other than passing parse_argv=True. This makes little sense in library use where sys.argv is empty, since it breaks for the case where no local configuration files exist with "input not specified".

[kynan]

For some background: The problem is illustrated by https://bitbucket.org/tarek/flake8/commits/d325cf7e7f4df3efe650dd7b26c8338d452fca53, a change I made to flake8 to allow the Git and Mercurial hooks to parse local configuration files, but which breaks if no configuration files are present. Unfortunately it is not possible to make this work for both cases without this change to pep8.

[kynan]

Any thoughts on this?

[sigmavirus24]

flake8 is dependent on this change @florentx

[kynan]

Some more explanation: Not specifying parse_argv causes pep8 to ignore any local config files: args and arglist are both empty in pep8.py:1843, which means the local config files are ignored because the loop in pep8.py:1773 is never executed.

[florentx]

In order to preserve backward compatibility, I would accept an additional keyword argument arglist in the StyleGuide constructor.

diff --git a/pep8.py b/pep8.py
index e38ab26..71aaf19 100755
--- a/pep8.py
+++ b/pep8.py
@@ -1571,11 +1571,12 @@ class StyleGuide(object):
     def __init__(self, *args, **kwargs):
         # build options from the command line
         self.checker_class = kwargs.pop('checker_class', Checker)
+        arglist = kwargs.pop('arglist', None)
         parse_argv = kwargs.pop('parse_argv', False)
         config_file = kwargs.pop('config_file', None)
         parser = kwargs.pop('parser', None)
-        options, self.paths = process_options(
-            parse_argv=parse_argv, config_file=config_file, parser=parser)
+        (options, self.paths) = process_options(
+            arglist, parse_argv, config_file, parser)
         if args or kwargs:
             # build options from dict
             options_dict = dict(*args, **kwargs)

It will be available in the flake8 function get_style_guide without change.

    flake8_style = get_style_guide(
        arglist=['.'],
        config_file=DEFAULT_CONFIG,
        **options)

[kynan]

OK, that would work for flake8. I'll send a pull request.

[kynan]

Done: #259

[florentx]

The other PR is merged

[florentx]

On second thought, I see the argument paths is already documented on the StyleGuide constructor. The arglist argument looks like a duplicate of this.
Maybe I'll revert the last fix and use the paths instead, it makes more sense.

[florentx]

Link: http://pep8.readthedocs.org/en/latest/api.html#pep8.StyleGuide

[sigmavirus24]

This should probably be better documented then. :)

[kynan]

@florentx I agree, using paths makes sense given that it's documented but not currently passed into process_options. I'm happy to propose another patch unless you prefer to fix it yourself.