Read options from config

[vsalvino]

This adds the ability to read options from a config file, such as setup.cfg, similar to how most other python tools work.

• Documented in README.
• Added basic unit test.

[sebweb3r]

Nice MR :-)

But, I would prefer .codespellrc or .codespell/config or something similar.

[vsalvino]

I am of the opposite mind, I prefer when all the tools can use one setup.cfg file 🙂 However I added the --config option to allow user to specify their own file.

[vsalvino]

OK - I also added a magic .codespellrc file for you.

[vsalvino]

Ok - I think this is finally ready to merge! On a separate note, it would be really helpful to have a requirements file and a contributing guide, to show how to run all of the various checks locally (unit tests, flake, etc.). Most of these are buried in the various CIs.

This is a really fantastic simple tool... I have been looking for a good native python spell checker for quite some time. Good work!

[larsoner]

However I added the --config option to allow user to specify their own file.

I would rather just support traversing a list -- it's more common with Python tools AFAIK. For example:

https://flake8.pycqa.org/en/latest/user/configuration.html#configuration-locations

To start, looking for .codespell then setup.cfg (with the right header) would be good.

If you don't feel like implementing this, I'd say just kill the --config option for now and only look for setup.cfg, and someone else in a follow-up PR can add other standard-ish filenames.

[peternewman]

@tomasbw does this do what you want?

[vsalvino]

To further clarify the order of config parsing:

• First parse from command line (to check for existence of --config option).
• Second parse from setup.cfg if it exists. This will override any cli args.
• Third parse from .codespellrc if it exists. This will override cli or setup.cfg.
• Fourth parse from file specified by --config, this will override cli, setup.cfg, .codespellrc.
• Fifth parse the command line again, to let it override any of the config file options.

[larsoner]

To further clarify the order of config parsing:

I think there is a problem with this hierarchy, I think command-line-passed arguments should have the highest priority. So in your list, it should be last, not first.

[peternewman]

A few comments

[larsoner]

Rather than re-calling this, would it be better to do:

if config.has_section(...):
    ...
    options = parser.parse_args(cfg_args)
else:
    options = argparse.NameSpace()

options = parser.parse_args(list(args), namespace=options)

If it's equivalent, it seems simpler/cleaner

[vsalvino]

It only re-parses if config.has_section(). The args have to be parsed first (line 372) before checking the config, to see if there is a --config option passed. And they have to be re-parsed at the end in order to override the options from the config file (which was the requested behavior). Following your suggestion, you would be re-parsing it twice if there were no config files, which seems pointless.

It's your project though, feel free to re-implement it yourself if you have a better idea.

[larsoner]

Ahh right, forgot about the need to parse to see the --config value. This should be fine then!

[larsoner]

Thanks @vsalvino

[peternewman]

I guess we should dog food? This bit of Travis might be interesting, we'll have to override our skip config:

    - codespell --check-filenames --skip="./.git/*,*.pyc,./codespell_lib/tests/test_basic.py,./codespell_lib/data/*,./example/code.c,./build/lib/codespell_lib/tests/test_basic.py,./build/lib/codespell_lib/data/*"
    # this file has an error
    - "! codespell codespell_lib/tests/test_basic.py"