Wiyh reliable caching schemes you don't need "clean" builds. Bazel and co (used by Google, FB, Twitter, etc) all use distributed build machines w/ caches. The

Wiyh reliable caching schemes you don't need "clean" builds. Bazel and co (used by Google, FB, Twitter, etc) all use distributed build machines w/ caches. The idea that you can't trust your incremental build and so need to discard it occasionally is a deep failure of how most incremental builds are done (mtime) and not a fundamental flaw in caching.