[Numpy-discussion] Moving away from svn ?

David Cournapeau david@ar.media.kyoto-u.ac...
Fri Jan 4 06:47:33 CST 2008

Ondrej Certik wrote:
> On Jan 4, 2008 12:56 PM, David Cournapeau <david@ar.media.kyoto-u.ac.jp> wrote:
>> Neal Becker wrote:
>>> There is a mercurial plugin for trac.
>> as well as a bzr one. The problem is more related to performance issues
>> (cheap things in svn are not cheap in DVCS, and vice-versa). For
>> example, the trac-bzr plugin is really slow for timelines (it takes
>> almost one second on a local server !); I have not tried the
>> trac-mercurial one much.
> We switched from svn to Mercurial in SymPy, I wrote some info here:
> http://code.google.com/p/sympy/wiki/Mercurial
> But basically, once you try "svn merge" and you go through all the pain
> and then try DVCS (I only use mercurial and git), you never want to come back.
Imagine the pain in the other direction, which was my experience :) I 
actually did not believe at first that it was so bad, and thought I was 
doing something wrong. At least, it certainly convinced me that SVN was 
not easier than DVCS.
> Our central repo is here:
> http://hg.sympy.org/sympy/
> and I can just fully recommend. We converted all our svn history to
> it, so now, I frequently
> browse the history of sympy (because every clone of the repo has it)
> if I need to look at something. I never used that with svn, because
> it's painfully slow.
I am not familiar with sympy: you are not using trac at all ? Also, how 
did you convert the svn history ?

I like the mercurial's way of showing branches and co; bzr does not have 
anything like that out of the box (there are separate projects to show 
sources; there is also launchpad of course, but since it is not open 
source, I do not even consider it for numpy/scipy).

On the other hand, the bzr community is more user-friendly: the tool is 
easier to use I think, the graphical tools are more advanced, at least 
from my experience.
> We were basically only deciding between git and Mercurial, but we
> chose mercurial, because
> * we are python guys and Mercurial is in python+C, very nicely written
> and they accept patches (Kirill, one sympy developer, has posted
> several already, to implement features he was missing - he used to use
> darcs before)
> * Sage uses it
For some time, the big problem of bzr was speed. But bzr accomplished 
quite a lot the last year: the first time I used mercurial, the speed 
difference was obvious; it is not so true anymore (they 'feel' the same, 
basically, but I have not used mercurial extensively, at least compared 
to bzr).

So I think it really boils down to the difficulty of the transition, the 
availability of third party tools (and also the tool used by other 
projects similar to numpy, as you mentionned).



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