public inbox for git@vger.kernel.org 
 help / color / mirror / Atom feed
* Octopus?  Really?  Interesting...
@ 2008-01-04 18:28 Jon Loeliger
  2008-01-04 22:42 ` Junio C Hamano
  0 siblings, 1 reply; 2+ messages in thread
From: Jon Loeliger @ 2008-01-04 18:28 UTC (permalink / raw)
  To: Git List

Guys,

So, I brain-wedged a merge here just now
and was surprised to see that a simple
fetch-n-merge yielded an octopus merge.
I was expecting a fast-forward.  So I went
back and reviewed.  What actually happend
was this:

    $ git checkout master
    $ git fetch origin
    # check it out... looks great ... let's merge it
    $ git merge master origin/master
    merge performed by octopus.

Oh, yeah.  Duh.  I did name two branches.  Feh.

Couple questions:

    Is it ever NOT the case, that if you are on one
    branch ("master") and name it as a "to be merged"
    branch along with some others, that we can simplify
    the request by noting that it is the same as the
    current "to be merged into" target branch?

    Other than creating a log message with "merged
    by octopus", will this merge be content-identical
    to the obvious simplified merge?

Thanks,
jdl

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Octopus?  Really?  Interesting...
  2008-01-04 18:28 Octopus? Really? Interesting Jon Loeliger
@ 2008-01-04 22:42 ` Junio C Hamano
  0 siblings, 0 replies; 2+ messages in thread
From: Junio C Hamano @ 2008-01-04 22:42 UTC (permalink / raw)
  To: Jon Loeliger; +Cc: Git List

Jon Loeliger <jdl@freescale•com> writes:

> Couple questions:
>
>     Is it ever NOT the case, that if you are on one
>     branch ("master") and name it as a "to be merged"
>     branch along with some others, that we can simplify
>     the request by noting that it is the same as the
>     current "to be merged into" target branch?

Yes we can, but "filter ancestors out from the remotes"
computation does not happen before the merge strategy is chosen.

>     Other than creating a log message with "merged
>     by octopus", will this merge be content-identical
>     to the obvious simplified merge?

I think octopus actually tries to be careful not to run the
read-tree 3-way merge when merging a true ancestor (see ll.77-87
in git-merge-octopus.sh, but see below), so the resulting tree
should be identical to "-s resolve" merge.

But that does not mean the user's wish to record such a commit
as one ancestor should not be honored, and I think there
actually is a benign bug there.  Due to the "Already up-to-date
with $SHA1" part, the codepath that says "Fast forwarding to:"
never actually triggers, so in practice we end up dropping any
true ancestor from the parent list of the resulting merge.  That
contradicts the comment in ll.77-87 that suggests we try not to
outsmart the user who told us to create such an octopus for
unfathomable reason ;-)

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2008-01-04 22:43 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-01-04 18:28 Octopus? Really? Interesting Jon Loeliger
2008-01-04 22:42 ` Junio C Hamano

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox