With Git, if you have an arbitrarily huge project, you can change branches and git will have changed all the files in the blink of an eye (from the terminal).
Git detects when any random file changed, again in the blink of an eye.
It manages to keep track of everything you do to any arbitrary file of your huge project, and if you commit, it does it immediately, as if's nothing to git to keep track of 100000+ files and see which changed and even which content in it changed.
So apparently, doing this is possible on a linux file system.
Why does IntelliJ need 10 minutes of "scanning files" before it finally opens your project?