Porting to new Python version

andrew cooke andrew at acooke.org
Thu Feb 19 14:20:16 CET 2009


maybe i should clarify that "easy" below is going to be relative.  the
process may end up being very hard due to various other reasons.  what i
was trying to explain is that

(1) 3 is probably going to require a separate branch from 2;

(2) that 2.6 and 3 can both be considered "latest";

(3) moving from 2.4 to 2.6 is probably best done before branching for 3;

(4) moving from 2.4 to 2.6 is probably easier than moving from 2 to 3.

andrew


andrew cooke wrote:
>
> i don't know what the context is, so it's hard for me to comment on the
> decision (i assume there are commerical pressures like customers not
> wanting to install old versions).
>
> however,if you go ahead, you need to think about exactly what you want to
> target.
>
> the latest version is really 3.0.1.  moving to 3 is probably not that hard
> (and there are tools to automate the process).  also, 2.6 is largely
> compatible with 3.  so moving to something that works with 2.6 and 3 is
> probably a reasonable target.  but that code will not work, without more
> significant effort, on 2.5 and earlier.
>
> so one idea would be to keep your existing code for 2.4, and update for 3.
>  for some time (years) you will need to support two versions, but if it is
> stable then that may not be much work.
>
> alternatively, you could ignore 3, which is not going to be mainstream for
> some time, and simply run against 2.6 and 2.5.  that should be even less
> work because you're staying with 2.  you could then say that your code
> works on 2.4 through 2.6
>
> or, finally, you could do the second step above (to get code that works on
> 2.4 to 2.6) and then the first step (to get a separate version that works
> on 3).  doing things in that order (with staged releases) lets you get
> most bug fixes for 2.5/6 into the code before branching for 3.
>
> hope that makes sense.
>
> disclaimer - i have not done the above; this is from reading various
> newsgroups and attempting to backport a project written in 3 to 2 (it was
> easy to go to 2.6, but i failed to get the same code to run on 2.5).
>
> andrew
>
>
>
>
>
> Gabor Urban wrote:
>> Hi,
>>
>> I have a tough issue: we are using a Python application written quite
>> a time ago for version 2.4. The code is mature, and there are no bugs.
>>  My bosses came up with the idea to port it to the latest release... I
>> am not really convinced that it's a good step.
>>
>> I wellcome any information pro and contra. I would like to get the
>> background as precisely as possible.
>>
>> Thanks in advance and good day to You!
>>
>> Gabor
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
>>
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
>





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