[alexhill]

I love it. Something I always wish for with linters is an easy way to run them only for the lines changed in a particular diff, to allow a codebase to gradually converge on consistency without breaking git blame by reformatting everything. Is there a nice way to do that for any Python linter?

[vjeux]

At Facebook we only tell you about lint violations for the lines you touch using arcanist from phabricator[1]. While it works great for most lint warnings, this hasn't worked that well for code formatters.

The most successful strategy was to add a flag in the file (@format in the header) to tell that a file is automatically formatted. The immediate benefit is that we enable format on save for developers on those files when they use Nuclide (>90% of penetration for JavaScript and Hack).

The other advantage is that when we release a new version of the formatter, we can re-run it on all those files so that people don't have lint warnings on code they already formatted in the past.

With that setup, there's a strong incentive for individual engineers to run the formatter on their team codebase in one PR and then everyone benefits from now on.

[1] https://secure.phabricator.com/

[philwelch]

Have you run into issues where the "let's reformat the entire codebase" commit makes `git blame` unusable?