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

From
LBLane Brooks <lane@brooks.nu>
Date
Jun 26, 2010, 00:35 UTC
Message-ID
<4C254B62.6020108@brooks.nu>
In-Reply-To
<20100626000358.GA11473@burratino>
On 06/25/2010 06:03 PM, Jonathan Nieder wrote:
Show 77 quoted lines
> Hi Lane,
>
> Lane Brooks wrote:
>
>    
>> 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.
>
>    
>> The 'my' branch forked off the 'main' line and for reasons out of my
>> control cannot merge the 'main' changes (D,E,F) back.
>>      
> [...]
>    
>> 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.
>
>    
>> 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

Previous: Jonathan NiederNext: Jonathan Nieder
Message 3 of 4 in “How to manage merges from one line while excluding its merges from another”
  1. Lane BrooksJun 25, 2010
  2. Jonathan NiederJun 26, 2010
  3. Lane BrooksJun 26, 2010
  4. Jonathan NiederJun 26, 2010

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