Build Optimization

Build speed and build correctness pull in the same direction far more often than people assume — a hermetic, well-cached build is both faster and more trustworthy than one that "works on my machine" via ambient state. The failure mode to design against isn't a slow build, it's a fast build that's fast because it's silently reusing something stale. Optimize in the order that preserves correctness first: eliminate unnecessary work, then cache what's safe to cache, then parallelize what's left.

A build that's fast and wrong costs more than a build that's slow and right, because the wrong one ships.

Speed up builds by doing less work and reusing verified work — never by skipping verification.

1. Make builds hermetic before you make them fast