Some of the changes in the 0.10.1 branch already are not bug fixes. Some break compatibility.
Having said that, at this level we should maintain a stable API and leave any changes for real version bumps. This should be only a bugfix release. Nacho On Tue, Nov 29, 2016 at 8:35 AM, Ismael Juma <ism...@juma.me.uk> wrote: > I disagree, but let's discuss it another time and in a separate thread. :) > > Ismael > > On Tue, Nov 29, 2016 at 4:30 PM, radai <radai.rosenbl...@gmail.com> wrote: > > > designing kafka code for stable extensibility is a worthy and noble > cause. > > however, seeing as there are no such derivatives out in the wild yet i > > think investing the effort right now is a bit premature from kafka's pov. > > I think its enough simply not to purposefully prevent such extensions. > > > > On Tue, Nov 29, 2016 at 4:05 AM, Ismael Juma <ism...@juma.me.uk> wrote: > > > > > On Sat, Nov 26, 2016 at 11:08 PM, radai <radai.rosenbl...@gmail.com> > > > wrote: > > > > > > > "compatibility guarantees that are expected by people who subclass > > these > > > > classes" > > > > > > > > sorry if this is not the best thread for this discussion, but I just > > > wanted > > > > to pop in and say that since any subclassing of these will obviously > > not > > > be > > > > done within the kafka codebase - what guarantees are needed? > > > > > > > > > > I elaborated a little in my other message in this thread. A simple and > > > somewhat contrived example: `ConsumerRecord.toString` calls the `topic` > > > method. Someone overrides the `topic` method and it all works as > > expected. > > > In a subsequent release, we change `toString` to use the field directly > > > (like it's done for other fields like `key` and `value`) and it will > > break > > > `toString` for this user. One may wonder: why would one override a > method > > > like `topic`? That is a good question, but part of the exercise is > > deciding > > > how we approach these issues. We could make the methods final and > > eliminate > > > the possibility, we could document it so that users can choose to do > > weird > > > things if they want, etc. > > > > > > Another thing that is usually good to think about is the expectation > for > > > `equals` and `hashCode`. What if subclasses implement them to have > value > > > semantics instead of identity semantics. Is that OK or would it break > > > things? > > > > > > Designing for implementation inheritance is generally complex although > > for > > > simple "record" like classes, it can be easier by following a few > > > guidelines. > > > > > > Ismael > > > > > > -- Nacho - Ignacio Solis - iso...@igso.net
