reflog-walk: apply --since/--until to reflog dates

When doing a reflog walk, we use the commit's date to do any date limiting. In earlier versions of Git, this could lead to nonsense results, since a skipped commit would truncate the traversal. So a sequence like: git commit ... git checkout week-old-branch git checkout - git log -g --since=1.day.ago would stop at the week-old-branch, even though the "git commit" entry further back is still interesting. As of the prior commit, which uses a parent-less traversal of the reflog, you get the whole reflog minus any commits whose dates do not match the specified options. This is arguably useful, as you could scan the reflogs for commits that originated in a certain range. But more likely a user doing a reflog walk wants to limit based on the reflog entries themselves. You can simulate --until with: git log -g @{1.day.ago} but there's no way to ask Git to traverse only back to a certain date. E.g.: # show me reflog entries from the past day git log -g --since=1.day.ago This patch teaches the revision machinery to prefer the reflog entry dates to the commit dates when doing a reflog walk. Technically this is a change in behavior that affects plumbing, but the previous behavior was so buggy that it's unlikely anyone was relying on it. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>