[Numpy-discussion] Moving away from svn ?

Robert Kern robert.kern@gmail....
Sun Jan 6 05:10:11 CST 2008


Bill Baxter wrote:
> On Jan 6, 2008 6:38 PM, Robert Kern <robert.kern@gmail.com> wrote:
>> Bill Baxter wrote:
>>> http://www.selenic.com/mercurial/wiki/index.cgi/MergeProgram
>>>
>>> This is a bit puzzling.  I understand better merging isn't the only
>>> reason to choose DVCS, but the above page basically says that
>>> Mercurial just uses whatever external merge program it can find.  So
>>> the file-level merging sounds like it must really be no different from
>>> other VCSs.
>>>
>>> So it is really just proper merging of directory renames and the like
>>> that make it superior?
>> No. If you'll pardon my repeating myself:
>>
>> """
>> DVCSes need to keep track of more information in order to be
>> distributed. That information is extremely useful for managing merges properly.
>> Centralized systems could track this information, but they don't *need* to in
>> order to be functional, so they mostly haven't, yet.
>>
>> For each revision, the DVCS knows what revisions it derives from. SVN does not
>> keep this information. SVN primarily just knows the text diffs from revision to
>> revision. In particular, if I have a long-lived branch, I am going to merge in
>> changes from the trunk while I'm working on it. When I go to merge the branch
>> back into the trunk, I need to know which trunk-revisions I've already merged
>> into the branch. SVN does not track this information. Tools like svnmerge.py
>> track some of this information at the expense of some added clumsiness.
>>
>> """
> 
> Ok.  Sorry for not reading that closer.  So what you're saying is that
> the magic is in the deciding of exactly which revisions of which files
> to run the merge program on?

That's the main idea.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco


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