I would like to add my few cents here.

I would suggest to stay away from code cleanup unless it is absolutely

I would also like to extend this discussion to understand the amount of
testing/QA to be performed before a release. How do we currently qualify a

Recently, we have ran into issues in ZK that I believe should have caught by
some basic testing before the release. I will be honest in saying that,
unfortunately, these bugs have resulted in questions being raised by several
people in our organization about our choice of using ZooKeeper.
Nevertheless, our product group really thinks that ZK is a cool technology,
but we need to focus on making it robust before adding major new features to

I would suggest to:
1. Look at current bugs and see why existing test did not uncover these bugs
and improve those tests.
2. Look at places that need more tests and broadcast it to the community.
Follow-up with test development.
3. Have a crisp release QA strategy for each release.
4. Improve API documentation as well as code documentation so that the API
usage is clear and debugging is made easier.



On Fri, Oct 15, 2010 at 9:44 AM, Thomas Koch <tho...@koch.ro> wrote:

> Hi Benjamin,
> thank you for your response. Please find some comments inline.
> Benjamin Reed:
> >   code quality is important, and there are things we should keep in
> > mind, but in general i really don't like the idea of risking code
> > breakage because of a gratuitous code cleanup. we should be watching out
> > for these things when patches get submitted or when new things go in.
> I didn't want to say it that clear, but especially the new Netty code, both
> on
> client and server side is IMHO an example of new code in very bad shape.
> The
> client code patch even changes the FindBugs configuration to exclude the
> new
> code from the FindBugs checks.
> > i think this is inline with what pat was saying. just to expand a bit.
> > in my opinion clean up refactorings have the following problems:
> >
> > 1) you risk breaking things in production for a potential future
> > maintenance advantage.
> If your code is already in such a bad shape, that every change includes
> considerable risk to break something, then you already are in trouble. With
> every new feature (or bugfix!) you also risk to break something.
> If you don't have the attitude of permanent refactoring to improve the code
> quality, you will inevitably lower the maintainability of your code with
> every
> new feature. New features will build on the dirty concepts already in the
> code
> and therfor make it more expensive to ever clean things up.
> > 2) there is always subjectivity: quality code for one code quality
> > zealot is often seen as a bad design by another code quality zealot.
> > unless there is an objective reason to do it, don't.
> I don't agree. IMHO, the area of subjectivism in code quality is actually
> very
> small compared to hard established standards of quality metrics and best
> practices. I believe that my list given in the first mail of this thread
> gives
> examples of rather objective guidelines.
> > 3) you may cleanup the wrong way. you may restructure to make the
> > current code clean and then end up rewriting and refactoring again to
> > change the logic.
> Yes. Refactoring isn't easy, but necessary. Only over time you better
> understand your domain and find better structures. Over time you introduce
> features that let code grow so that it should better be split up in smaller
> units that the human brain can still handle.
> > i think we can mitigate 1) by only doing it when necessary. as a
> > corollary we can mitigate 2) and 3) by only doing refactoring/cleanups
> > when motivated by some new change: fix a bug, increased performance, new
> > feature, etc.
> I agree that refactoring should be carefully planned and done in small
> steps.
> Therefor I collected each refactoring item for the java client in a small
> separate bug in https://issues.apache.org/jira/browse/ZOOKEEPER-835 that
> can
> individually be discussed, reviewed and tested.
> Have a nice weekend after Hadoop World!
> Thomas Koch, http://www.koch.ro

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