Re: [PATCH 00/15] submodule groups (once again)

Stefan Beller [off-list ref] writes:

git diff is supposed to view the differences between "what would I
get after checkout" (i.e. what is in the index run through smudge filters)
compared to the actual worktree.

I do not think it affects your conclusion, but the above is wrong.
"git diff" is a preview of what you would add (i.e. what will be in
the index after passing working tree contents via the clean filter)
relative to what is actually in the index.