With history simplification, we still show merges that are required
to make the history _complete_, i.e. say that you had:
a
|
b
/ \
c d
| |
and neither "a" nor "b" actually changed the file, but both "c" and "d"
did: in this case we have to leave "b" around just because otherwise there
would be no way to show the _relationship_, even if "b" itself doesn't
actually change the tree in any way what-so-ever.
It would make sense to make that further simplification if the
"--parents" flag wasn't present. In that case the user is
literally asking for a list of commits and is not interested in
the relationship between them.
This patch also fixes a real bug. Without this patch, the
"--parents --full-history" combination (which you'd get if you
do something like
gitk --full-history Makefile
or similar) will actually _drop_ merges where all children are identical.
That's wrong in the --full-history case, because it means that the graph
ends up missing lots of entries.
In the process, this also should make
git-rev-list --full-history Makefile
give just the _true_ list of all commits that changed Makefile (and
properly ignore merges that were identical in one parent), because now
we're not asking for "--parent", so we don't need the unnecessary merge
commits to keep the history together.
Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>