What used to happen is that diffcore_count_changes() simply ignored any
hashes in the destination that didn't match hashes in the source. EXCEPT
if the source hash didn't exist at all, in which case it would count _one_
destination hash that happened to have the "next" hash value. As a
consequence, newly added material was often undercounted, making output
from --dirstat and "complete rewrite" detection used by -B unrelialble.
This changes it so that:
- whenever it bypasses a destination hash (because it doesn't match a
source), it counts the bytes associated with that as "literal added"
- at the end (once we have used up all the source hashes), we do the same
thing with the remaining destination hashes.
- when hashes do match, and we use the difference in counts as a value,
we also use up that destination hash entry (the 'd++').
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>