[Numpy-discussion] Using svnmerge on numpy: am I missing something ?

[David Cournapeau]

Fernando Perez wrote:
> On Jan 7, 2008 10:41 PM, David Cournapeau <david at ar.media.kyoto-u.ac.jp> wrote:
>   
>> Hi,
>>
>>     for my work related on scons, I have a branch build_with_scons in
>> the numpy trunk, which I have initialized exactly as documented on the
>> numpy wiki (http://projects.scipy.org/scipy/numpy/wiki/MakingBranches).
>> When I try to update my branch with the trunk, I got suprising merge
>> request, in perticular, it tried to merge all trunk revision up to 2871,
>> whereas I created my branch with a copy from the trunk at revision 4676.
>> Am I missing something ? Shouldn't it try to merge from the revision I
>> started the branch (since this revision is a common ancestor) ?
>>     
>
> AFAIK, the merge command must ALWAYS be given with explicit revision
> brackets, since this is precisely the information SVN does not track
> at all.  Quoting:
>
> http://svnbook.red-bean.com/en/1.0/ch04s04.html
> """
> But as discussed in the section called "Best Practices for Merging",
> you don't want to merge the changes you've already merged before; you
> only want to merge everything "new" on your branch since the last time
> you merged. The trick is to figure out what's new.
>
> The first step is to run svn log on the trunk, and look for a log
> message about the last time you merged from the branch:
>
> $ cd calc/trunk
> $ svn log
> …
> ------------------------------------------------------------------------
> r406 | user | 2004-02-08 11:17:26 -0600 (Sun, 08 Feb 2004) | 1 line
>
> Merged my-calc-branch changes r341:405 into the trunk.
> ------------------------------------------------------------------------
> …
>
> Aha! Since all branch-changes that happened between revisions 341 and
> 405 were previously merged to the trunk as revision 406, you now know
> that you want to merge only the branch changes after that—by comparing
> revisions 406 and HEAD.
> """
>
> As you can see, they recommend that you indicate in that particular
> log message the revision brackets of what you've already merged, so
> you can find that information easily later. Once you have this
> information on record, you start doing all your future updates on the
> branch with specific revision ranges, and that seems to work
> reasonably well.
>
>   
I understand this if doing the merge at hand with svn merge (that's what 
I did previously), but I am using svnmerge, which is supposed to avoid 
all this (I find the whole process extremely error-prone). More 
specifically, I am surprised by the svnmerge starting revisions,

cheers,

David