Dmitry Kulikov [off-list ref] writes:
I have found a problem.
It turned out, that the timestamp used to determinate which commit is later
the given date is not at 0h 0m 0s, Instead it is at the current time.
Similarly --until=<date> uses not 23h 59m 59s but also current time.
The behaviour is as designed. "git log --since=yesterday" does the
same "as nobody said which hour and minute, we take it to mean this
time yesterday".
You of course can say "git log --since=yesterday.midnight" if you
want to be exact ;-).