Today I learned about the black formatter tool for Python source code. The name is a play on the Henry Ford quote “Any customer can have a car painted any color that he wants so long as it is black.”
The idea is that black is not configurable. Now I love to dig into configuration options (it’s a great way to procrastiwork), but this really struck me: If you are not allowed to tweak any options, it really reduces the mental load over which ones are the “right fit” for the project. This could be especially freeing if you are working on a large repository over time, or if you are collaborating.
I have found that my style tends to “drift” over time, especially in Python. I’d like to say that I’m a devout follower of the PEP-8 gospel, but the truth is I waver. I usually like my code style “the way I like it”, which is usually whatever is aesthetically most pleasing to me at the time, and what I consider most readable. But aesthetic choices drift… So better to not have any control of it at all! (Yes, I know that Go was created on this philosophy, but I don’t do all that much Go programming.)
The beauty of black is the lack of options — a particular project manager can’t make any decisions about the “right” style for the project, so there can’t be any discussions of the merits of those choices. black will format according to PEP-8 (actually, according to pycodestyle), and that’s that.
So, I’m going to try this out in a new library I’m building that will collect some scripts I’ve been using to work on CSV and other text-based formats. My plan is to always require black formatting before any commit. To help with this, I created a pre-commit hook in git that basically does the following:
- Run
black --check *.pyand see if it finds any issues. - If no issues were found, great! Let the commit proceed.
- If issues were found, output the report from
blackand tell the user to fix it before committing.
I’m hoping this will help free me from “worrying” about formatting in this library, and allow me to focus on what matters — making useful tools. We’ll see how it goes…