Re: git-diff on touched files: bug or feature?

Alexandre Julliard [off-list ref] writes:

.... For
instance in vc-git.el the workfile-unchanged-p function currently has
to rehash the file every time to see if it really changed, because we
can't afford to refresh the whole project at that point.

Maybe I am missing something.  Why can't you "afford to"?

"update-index --refresh" looks at only the files whose cached
stat information does indicate there might be chanegs.  It does
not rehash already up-to-date ones.