[ZODB-Dev] RFC: Proposed backward-compatibility policy
Jim Fulton
jim at zope.com
Wed Oct 27 14:21:23 EDT 2004
Jeremy Hylton wrote:
> On Wed, 27 Oct 2004 12:53:44 -0400, Jim Fulton <jim at zope.com> wrote:
>
>>2. Backward compatibility support will be limited. When we make a
>> change that would require a change in software or data, we'll add
>> code to support the old software or data, but we will also add
>> code to generate deprecation warnings when that support code is
>> used. The deprecation warnings will say specifically when the
>> backward-compatibility support will go away. This time will
>> usually be expressed as a release number at least two feature
>> releases past the next feature release. (For example, if the next
>> feature release is release 3.4, then the backward compatibility
>> support would not be removed any sooner than release 3.6.) In
>> other words, we will limit the time extent of backward
>> compatibility support, but we will give plenty of warning.
>
>
> How does this apply in the near term? The cat is already out of the
> bag for 3.3,
Right, so this applies to 3.4.
> which probably isn't fully backwards compatible.
I think we should look at backward compatabilities on a
case-by-case basis and we may very well want to treat some of
them as bugs.
> Would
> you consider those bugs that would be fixed in a 3.3 maintenance
> release?
Potentially. We need to look at the specifics.
> For example, I don't think the ZEO protocol for 3.3 isn't
> compatible with the ZEO protocol for 3.2. In addition to data and
> code, it might be worthwhile to say something in the policy about zeo
> protocol compatibility.
Perhaps.
>
>
>>3. It is very important to catch backward compatibility problems
>> during development of new releases. In particular, it is
>> important to test new ZODB releases before they are released in
>> final form. If a backward-compatibility problem is found before
>> the final release, it will be considered a bug and will be fixed
>> (by adding backward compatibility support) if at all possible
>> before the final release. After the final release, we may choose
>> not to bother to fix backward-compatibility problems. Consumers of
>> ZODB have a right to backward compatibility, but they also have a
>> responsibility to test ZODB against their applications during the
>> beta release cycle (or sooner) to make sure their applications
>> work.
>
>
> Does this mean that consumers who depend on subtle features are out of
> luck if they don't test the alphas or betas?
Yes
> I think that may be the
> only practical thing to do. There are too many under-documented
> corners of ZODB to be thorough about testing without help from users.
Exactly.
Jim
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