Doesn't ADD do the download unconditionally but only invalidate the cache if the contents change? The only good use for ADD that I've found is for invalidating

Doesn't ADD do the download unconditionally but only invalidate the cache if the contents change? The only good use for ADD that I've found is for invalidating git clones from GitHub: ADD https://api.github.com/repos/<user>/<repo>/git/refs/heads/<branch> version.json RUN git clone --depth=1 --single-branch --branch=<branch> https://github.com/<user>/<repo>.git