Ask HN: What open source project, in your opinion, has the highest code quality?

I'm planning to study a number of these codebases to gain insight and inspiration. Maybe even write an article about their commonalities...

The test suite for SQLite is very impressive.

> The reliability and robustness of SQLite is achieved in part by thorough and careful testing. As of version 3.23.0 (2018-04-02), the SQLite library consists of approximately 128.9 KSLOC of C code. (KSLOC means thousands of "Source Lines Of Code" or, in other words, lines of code excluding blank lines and comments.) By comparison, the project has 711 times as much test code and test scripts - 91772.0 KSLOC.

Plus they have a whole page on their site about testing [1]. Which is more then you can say about a lot of open source projects.

[1] https://www.sqlite.org/testing.html

While I wouldn't suggest that his code is meant to be read for beauty/inspiration, djb's code is of incredibly high quality.

I would suggest starting with qmail and looking at the (very mainstream) patches that people are running on top of it.

tinydns is also worth a look.

Laravel is incredibly well crafted and documented, one of the highest quality OSS projects ever, IMHO.

One of the most dumbfounding things I've encountered throughout my career is the python community's dogged persistence at avoiding using libcurl.