Re: performance problem: "git commit filename"

Junio C Hamano [off-list ref] writes:

The fact that we write out a temporary index and then rebuild
the real index means CE_UPTODATE flag we populate in the
temporary index is lost and we still need to lstat(2) while
building the real index, which is a bit unfortunate.  I suspect
that we can use the one-way merge to reset the index when
building the real index after we are done building the temporary
index, instead of discarding the in-core temporary index and
re-reading the real index.

This comment is completely bogus.  With your earlier one-way
merge fix, as the way CE_UPTODATE patch was written we preserve
in-core CE_UPTODATE bit across write_index(), the code already
should be taking advantage of an earlier lstat(2).