I'm helping someone build their first snap of a rust application, and after successfully building the snap for the first time, snapcraft correctly warned that there are missing stage packages. So we added the stage packages to the part, re-ran snapcraft, and it's fully rebuilding the part (150 rust crates). No build-packages were added, so it doesn't feel right to clean and rebuild a part if only stage packages were added. Or am I missing a good reason for doing that?