Some tools (like linters) might need to look at the actual changes that occurred for various reasons, such as to avoid doing redundant work on unmodified files.

Some tools (like linters) might need to look at the actual changes that occurred for various reasons, such as to avoid doing redundant work on unmodified files. To do that, you need all the merge bases... which can present a kind of a chicken-and-egg problem because, to figure this out with git, you need the commits to be there locally to begin with. I'm sure you can find a way around it if you put enough effort into scripting against the remote git server, but you might need to deal with git internals in the process, and it's kind of a pain compared to just cloning the whole repo.