[solatic]

> I've said for a long time that composability in software is a bit like playing Tetris: the lines have to clear.

I love this analogy, and I find it darkly hilarious that most sibling commenters don't seem to understand. Maybe you need to have worked within a million-line codebase to get it.

The only way to "clear the lines" in software is to eject them from the main codebase and into imported libraries with stable, well-documented, well-tested APIs that you very rarely if ever (security vulnerabilities?) need to touch after "stabilizing" them. Great public examples: the Go standard library, https://github.com/spf13/viper , https://github.com/uber-go/zap . Viper and zap combined are more than 20,000 lines of code (according to cloc) that I don't need to read or understand how they work - their lines have been "cleared" and all I need to know is the abstraction.

Half the joy to be found when working within massive codebases is successfully clearing lines.