Re: [PATCH v2 3/3] Add option to transpose parents of merge commit

[Junio C Hamano <gitster@pobox.com>]

Johannes Sixt <j.sixt@viscovery.net> writes:

> Am 11/28/2012 0:00, schrieb Kacper Kornet:
>> When the changes are pushed upstream, and in the meantime someone else
>> updated upstream branch git advises to use git pull. This results in
>> history:
>> 
>>      ---A---B---C--
>>          \     /
>>           D---E
>
> The commit message will say:
>
>   Merge branch 'master' of /that/remote
>
>   * 'master' of /that/remote:
>     E
>     D
>
>> where B is the local commit. D, E are commits pushed by someone else
>> when the developer was working on B. However sometimes the following
>> history is preferable:
>> 
>>     ---A---D---C'--
>>         \     /
>>          '-B-'
>
> Better:
>
>      ---A--D--E--C'
>          \      /
>           `----B

Yup, that topology is what Kacper's workflow wants.

Stepping back a bit, however, I am not sure if that is really true.
The goal of this topic seems to be to keep one integration branch
and always merge *into* that integration branch, never *from* it,
but for what purpose?  Making the "log --first-parent" express the
integration branch as a linear series of progress?  If so, I suspect
a project with such a policy would dictate that D and E also be on a
side branch, i.e. the history would look more like this:

      D---E
     /     \
  --A-------X---C---
     \         /
      `-------B

with X being a --no-ff merge of the topic that consists of these two
commits.

> In this case, the commit message should say... what? Certainly not the
> same thing. But I do not see that you changed anything in this regard.

True.  If the goal is to emulate a merge of B from a side branch
into _the_ integration branch, the summary should also emulate the
message that would be given when the remote pulled from your current
branch.