Re: [GIT PULL] use generic pci_iomap on all architectures

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jan 11, 2012, 02:52 UTC
Message-ID: <CA+55aFwxaGXkJrpKXRFWEamAyF+a2+ypm7B6LLRzT0JpZp_0pg@mail.gmail.com>
In-Reply-To: <7vipkj7ykd.fsf@alter.siamese.dyndns.org>

On Tue, Jan 10, 2012 at 6:38 PM, Junio C Hamano <gitster@pobox.com> wrote:

>
> The parameter to "git shortlog" that appears later should also be updated
> to match this, by the way, even though that should not affect the outcome
> in any way.

No, don't do that part.

Why?

Remember: there can be *multiple* merge bases. The expression

    git shortlog ^$baserev $headrev

always works, but changing "baserev" to "merge_base" will suddenly break for the multiple merge-bases case.

> I am however not sure what would happen when there are more than one merge
> bases. I guess those who throw pull requests are not supposed to be doing
> merges in reverse direction, so it should not matter ;-)

The other cases don't really care. For them, "show one merge-base" is fine, and they are "end-point" operations (like "diff") that really cannot handle a set of commits anyway.

But for "git shortlog", switching to using the merge base would actually start showing commits that shouldn't be shown. It's fundamentally a set operator, and does the right thing in the presense of multiple merge-bases (which "diff" and "since commit XYZ" are clearly not set operators, although arguably you could try to show all merge bases for the "since" case).

                       Linus