Re: How to manage merges from one line while excluding its merges from another

On 06/25/2010 06:03 PM, Jonathan Nieder wrote:

Hi Lane,

Lane Brooks wrote:

   

quoted

I have a tree like this:

      G---H---I---J---K   devel
     /       /       /
A---B---C---D---E---F    main
         \
          L---M---N---O   my
     

Nice diagram.

What is missing is a picture of what you want the result to be.

   

quoted

The 'my' branch forked off the 'main' line and for reasons out of my
control cannot merge the 'main' changes (D,E,F) back.
     

[...]
   

quoted

I want to continue to merge from the devel line as additional commits
are made that are not on the main branch, but I do not want any of
the future merge commits.
     

(I) I am guessing that the 'main' line is not part of the published
history, in which case you what you want might look like this:

          ... devel
       /
  A---B---C- ... main
           \
            L---M---N---O---H'---J' my

The J commit itself could not be included in the history of the 'my'
branch because its ancestor D is not meant to be published.

(II) In an alternative scenario, the 'main' changes (D, E, F) are
forbidden because they introduce bugs.  In this case, a solution might
look something like this:

        ...                  K devel
      /               /       \
A---B---C---D---E---F main    \
          \                     \
           L---M---N---O---------P---Q---R---S

where Q, R, and S are commits (created with ‘git revert’) that
undo the effect of F, E, and D.  From then on, you can just merge
from devel as usual.

   

quoted

Is there an automated way to do this or do I have to cherry pick
everything by hand?
     

In git 1.7.2, you will be able to automate (I) as follows:

  git cherry-pick --no-merges ^my ^main devel

Until then, you might want to try experimenting with something
like this:

  git rev-list --no-merges ^my ^main devel |
  while read rev
  do
	git cherry-pick $rev ||
	{
		echo>&2 cherry-pick failed
		break
	}
  done

Hope that helps,
Jonathan
   

I guess (I) is what I want, but your enumerating those two options makes 
me wonder how well things will go when 'devel' and 'main' merge and then 
'my' needs to merge in from 'main'. Seems like a disaster waiting to happen.

I'll take a look at your suggested cherry-pick script. Can it be rerun 
multiple times or is it run one-time only. In others, as 'devel' 
continues to grow can I run it again and will it cherry-pick 
intelligently or will it try to reapply commits already cherry-picked?

Thanks,
Lane