Re: [PATCH] Additional merge-base tests

A Large Angry SCM [off-list ref] writes:

It works[*] and it does what using the timestamp was trying to
do. Namely, work from "more recent" (or "closer") commits toward
"older" (or "farther") commits until you've gone past the point you
care about.

If you really really care, now we have clear_commit_marks() with
get_merge_bases() infrastructure in, you _could_ run another
round of get_merge_bases() on the commit on the result list to
see which ones are reachable from others by performing an
equivalent of fast-forward/already-up-to-date check.