Re: [PATCH 3/5] gitignore: read from index if .gitignore is not in worktree

Nguyễn Thái Ngọc Duy  [off-list ref] writes:

this allows to use .gitignore in sparse mode, where .gitignore may or
may not be checked out (CE_VALID)

Hmm, do we have a guarantee that we have read the index when .gitignore is
used in all the codepath in the current codebase?

"git add" used to do the fill_directory() traversal before reading the
index in some cases back in v1.6.0 days for a reason.  "git add" does not
do so anymore, but I am wondering if there are others.