"*End-to-end / crash-only*. Ninja is not a persistent daemon process but instead does all its work from scratch on each execution. This is intentional and a mixture of the insights of the end-to-end principle and crash only software, which is to say: given that you need to run Ninja from scratch sometimes, if you make that fast, then you don't need to build a second "online" codepath. Projects that can stay memory-resident tend to eventually let their startup performance languish." <- pants basically went the "online" codepath route