Is the date the repost was published 2018, or the date Carmack originally published? My first thought to

> Rolling back code and rebuilding to run a test is a pain

was “bisecting with distributed version control” isn’t that hard. The rest of the article doesn’t definitively place it in any era. If I’m reading this correctly, he’s essentially advocating for a/b(/c/d ...) testing and feature flags?

So interested to know when this idea occurred to him, and read this HN discussion.

Regardless, the idea (“competing” or alternate implementations in the same build) is compelling.