Deprecation period (was Re: [Zope3-dev] BBB and Deprecation Warnings)

[Dieter Maurer]

Tim Peters wrote at 2006-1-4 14:51 -0500:
>[Dieter Maurer]
>> If the backward compatibility period gets shorter,
>> we will skip more and more releases because of the increased burden
>> to get our applications running again...
>
>Well, every new release will remove features deprecated N releases
>ago, where N is presumably some constant whose value is being debated
>here.  That will be so in steady state whether N is 1 or 10 (i.e., the
>value of N doesn't really matter to that):  the pressure to recode
>(and your temptation to skip releases) is related more to the
>frequency of releases than to the length of the deprecation grace
>period.

In fact, whether I upgrade or not depends on the merits of the
new version (with respect to that currently used) and the effort
necessary for the upgrade.

You are right that the (long term) average number of features removed in
a given release depends on the time between releases but not
the length of the deprecation period.

However, a long deprecation period allows to cluster the renewal work.
If the deprecation period is e.g. 4 releases, then I can
3 times upgrade without to worry about deprecations if I am ready
to resolve all deprecation problems in the 4 th one.
This increased clustering gives more flexibility to do the
renewal work at times when projects are not to heavily pressing.


-- 
Dieter