[Svnmerge] svnmerge rewritten in Python

[Giovanni Bajo]

Jim Fulton <jim at zope.com> wrote:

>> This is interesting. This behavior, getting the return status
>> as a result of a close of a file returned by popen4, is inconsistent
>> with the Python library documentation.

I read this in the os.popen documentation:

"""
The exit status of the command (encoded in the format specified for wait()) is
available as the return value of the close() method of the file object, except
that when the exit status is zero (termination without errors), None is
returned
"""

So I'd say this is documented, but it does not work under Linux for some
reason. There, you need to use wait(). Maybe it's a difference on how the pipes
work at the kernel level. Module subprocess was added exactly to abstract these
issues, and it does that very well. I just did not want to use it because I
want to retain Python 2.0 compatibility.

>> I still think it would be cleaner to get data back from
>> the apis than to parse output.


Yes, generically speaking, it's better to get access to data without
marshalling everything to strings and back everytime. But for this script, I
believe it's much better to keep the code size low, the external dependencies
as minimum as possible, and the compatibility as high as possible. Using the
svn client is a simple way to achieve this.

Notice we already have a dark corner, see get_repo_root which is ugly and slow.
If those cases grew in number, I'd be more in favor of using the bindings.

>>> Can you show us your working-in-progress script?
>>
>> Sure.  It doesn't really work at all.  I was working on a doc test
>> and was in the middle of implementing init.


Thanks, I'll give it a look ASAP.

>> I strongly recommend automated tests included with the script --
>> preferably as doc tests.  You should be able to get an idea of the
>> testing approach I was following in my script.


Sure, testing is fundamental. I tend to do unittest mainly, but I'll play with
doctests for this. I'm gonna have a full weekend, so let's see if I find some
time on monday.

BTW, given also the other discussions and the improvements we are planning, I'm
going to put the script in a SVN repo of mine to handle development easier (I
feel uncomfortable working without patches and SCM).

Thanks for your feedback, it is really appreciated!

Giovanni Bajo