Re: How to selectively recreate merge state?

From: Jakub Narebski <jnareb@gmail.com>
Date: Dec 11, 2009, 11:20 UTC
Message-ID: <200912111220.40844.jnareb@gmail.com>
In-Reply-To: <4B222289.6000004@drmicha.warpmail.net>

Dnia piątek 11. grudnia 2009 11:44, Michael J Gruber napisał:

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> Jakub Narebski venit, vidit, dixit 11.12.2009 02:33:
>> Dnia piątek 11. grudnia 2009 02:11, Junio C Hamano napisał:
>>> Jakub Narebski <jnareb@gmail.com> writes:
>>>
>>>>   --unresolve::
>>>>         Restores the 'unmerged' or 'needs updating' state of a
>>>>         file during a merge if it was cleared by accident.
>>>>
>>>> Unless "git add foo" not only adds current contents of foo at stage 0,
>>>> but also removes higher stages from index...
>>>
>>> By definition, adding anything at stage #0 is to remove higher stages.
>> 
>> Hmmm... let's test it:
>> 
>>  $ git merge side-branch 
>>  Auto-merging foo
>>  CONFLICT (content): Merge conflict in foo
>>  Automatic merge failed; fix conflicts and then commit the result.
>>  $ git ls-files --stage
>>  100644 257cc5642cb1a054f08cc83f2d943e56fd3ebe99 1       foo
>>  100644 3bd1f0e29744a1f32b08d5650e62e2e62afb177c 2       foo
>>  100644 469a41eda5c8b45503a3bfc32ad6b5decc658132 3       foo
>>  $ <edit foo>
>>  $ git add foo
>>  $ git ls-files --stage
>>  100644 a1b58d38ffa61e8e99b7cb95cdf540aedf2a96b3 0       foo

I thought that "git add foo" only adds current contents of foo in stage 0,
and does not delete other stages.
 
Unless "git add foo" does more than "git update-index foo" does here.

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>> Now let's test '--unresolve' option of git-update-index:
>> 
>>  $ git update-index --unresolve foo
>>  $ git ls-files --stage foo
>>  100644 3bd1f0e29744a1f32b08d5650e62e2e62afb177c 2       foo
>>  100644 469a41eda5c8b45503a3bfc32ad6b5decc658132 3       foo
>> 
>> WTF? What happened to stage 1 (ancestor)?
> 
> 2 and 3 are easy (cheap) to recreate from HEAD and MERGE_HEAD, 1 is not.
> I guess that's why --unresolve doesn't even attempt to do anything with 1.

But then "git update-index --unresolve <file>" is next to useless.

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>> 
>>  $ git checkout --conflict=merge foo
>>  error: path 'foo' does not have all three versions
>> 
>> Let's recover it by hand:
>> 
>>  $ echo -e "100644 257cc5642cb1a054f08cc83f2d943e56fd3ebe99 1\tfoo" | 
>>    git update-index --index-info
>>  $ git ls-files --stage foo
>>  100644 257cc5642cb1a054f08cc83f2d943e56fd3ebe99 1       foo
>>  100644 3bd1f0e29744a1f32b08d5650e62e2e62afb177c 2       foo
>>  100644 469a41eda5c8b45503a3bfc32ad6b5decc658132 3       foo
>>  $ git checkout --conflict=merge foo
> 
> Yeah, if we knew that sha1...

Isn't it:

  $ git ls-tree $(git merge-base HEAD MERGE_HEAD) -- foo

or

  $ git rev-parse "$(git merge-base HEAD MERGE_HEAD):foo"

-- 
Jakub Narebski
Poland