[Python-Dev] SVN <-> HG workflow to split Python Library by Module

[Brett Cannon]

On Fri, Jul 2, 2010 at 17:17, David Cournapeau <cournape at gmail.com> wrote:
> On Sat, Jul 3, 2010 at 6:37 AM, Brett Cannon <brett at python.org> wrote:
>> On Fri, Jul 2, 2010 at 12:25, anatoly techtonik <techtonik at gmail.com> wrote:
>>> I planned to publish this proposal when it is finally ready and tested
>>> with an assumption that Subversion repository will be online and
>>> up-to-date after Mercurial migration. But recent threads showed that
>>> currently there is no tested mechanism to sync Subversion repository
>>> back with Mercurial, so it will probably quickly outdate, and the
>>> proposal won't have a chance to be evaluated. So now is better than
>>> never.
>>>
>>> So, this is a way to split modules from monolithic Subversion
>>> repository into several Mercurial mirrors - one mirror for each module
>>> (or whatever directory structure you like). This will allow to
>>> concentrate your work on only one module at a time ("distutils",
>>> "CGIHTTPServer" etc.) without caring much about anything else.
>>> Exceptionally useful for occasional external "contributors" like me,
>>> and folks on Windows, who don't possess Visual Studio to compile
>>> Python and are forced to use whatever version they have installed to
>>> create and test patches.
>>
>> But modules do not live in an isolated world; they are dependent on
>> changes made to other modules. Isolating them from other modules whose
>> semantics change during development will lead to skew and improper
>> patches.
>
> I cannot comment on the original proposal, but this issue has known
> solutions in git, in the form of submodules. I believe hg has
> something similar with the forest extension
>
> http://mercurial.selenic.com/wiki/ForestExtension

Mercurial has subrepo support, but that doesn't justify the need to
have every module in its own repository so they can be checked out
individually.