Hello Gitters,
I wonder if I might pick your brains on the best way to handle a
situation I found myself in recently:
We have an integration branch, and a master branch, and a topic branch
that was based on the integration branch. Graphically:
A-o-o-o-o-o-o-o-o-o-E-(master)
\
o-o-B-o-o-o-o-M-o-o(integration)
\ /
C-o-o-D (topic)
I wanted to introduce this branch onto master to end up with:
A-o-o-o-o-o-o-o-o-o-E-----------N (master)
\ \ /
\ C'-o-o-D' (topic-rebased)
\
o-o-B-o-o-o-o-M-o-o(integration)
\ /
C-o-o-D (topic)
(ASCII art reproduced at http://dpaste.org/GUmM/ lest it be munged)
While it's easy to create comit N once I have commit D' (with git
merge --no-ff), I found that it's not at all easy to work out where
commit B is in order to do do a rebase --onto master B.
My usual approach would be to try and use git merge-base, but because
the topic branch is already merged into the integration branch, that
doesn't give useful output.
Is there a good way around this?
Conrad
On Sat, Jul 30, 2011 at 05:54:59PM -0700, Conrad Irwin wrote:
I wanted to introduce this branch onto master to end up with:
A-o-o-o-o-o-o-o-o-o-E-----------N (master)
\ \ /
\ C'-o-o-D' (topic-rebased)
\
o-o-B-o-o-o-o-M-o-o(integration)
\ /
C-o-o-D (topic)
(ASCII art reproduced at http://dpaste.org/GUmM/ lest it be munged)
While it's easy to create comit N once I have commit D' (with git
merge --no-ff), I found that it's not at all easy to work out where
commit B is in order to do do a rebase --onto master B.
If you know M, then B is the merge-base of M^1 and M^2 (i.e., the
parents of M). If you don't know M, but do know D, you can find it by
walking backwards from "integration" until you find a merge commit with
D as its second parent (e.g., by grepping "rev-list --parents").
Make sense?
-Peff
On Sat, Jul 30, 2011 at 10:53 PM, Jeff King [off-list ref] wrote:
On Sat, Jul 30, 2011 at 05:54:59PM -0700, Conrad Irwin wrote:
If you know M, then B is the merge-base of M^1 and M^2 (i.e., the
parents of M). If you don't know M, but do know D, you can find it by
walking backwards from "integration" until you find a merge commit with
D as its second parent (e.g., by grepping "rev-list --parents").
Make sense?
Yup. git rev-list was definitely the tool I was missing, thank you :).
Conrad
merge=$(git rev-list --parents integration |\
grep " $(git rev-parse topic)" | cut -d' ' -f 1)
split=$(git merge-base $merge^ $merge^2)
git rebase --onto master $split
git checkout master
git merge --no-ff topic