that's a valid concern. If api backward compatibility is not maintained or minimized, it will be painful for production code upgrade.
On Mon, Oct 28, 2013 at 3:29 PM, Mark Hamstra <[email protected]>wrote: > While that is good, it really isn't good enough. Requiring updated source > code for everything that uses Spark every time Spark goes from x.y.z to > x.y.(z+1) is not going to win many friends among developers building on top > of Spark. Quite the opposite. > > > On Mon, Oct 28, 2013 at 3:25 PM, Reynold Xin <[email protected]> wrote: > > > Hi Mark, > > > > I can't comment much on the Spark part right now (because I have to run > in > > 3 mins), but we will make Shark 0.8.1 work with Spark 0.8.1 for sure. > Some > > of the changes will get cherry picked into branch-0.8 of Shark. > > > > > > On Mon, Oct 28, 2013 at 6:22 PM, Mark Hamstra <[email protected] > > >wrote: > > > > > Or more to the point: What is our commitment to backward compatibility > in > > > point releases? > > > > > > Many Java developers will come to a library or platform versioned as > > x.y.z > > > with the expectation that if their own code worked well using x.y.(z-1) > > as > > > a dependency, then moving up to x.y.z will be painless and trivial. > That > > > is not looking like it will be the case for Spark 0.8.0 and 0.8.1. > > > > > > We only need to look at Shark as an example of code built with a > > dependency > > > on Spark to see the problem. Shark 0.8.0 works with Spark 0.8.0. > Shark > > > 0.8.0 does not build with Spark 0.8.1-SNAPSHOT. Presumably that lack > of > > > backwards compatibility will continue into the eventual release of > Spark > > > 0.8.1, and that makes life hard on developers using Spark and Shark. > For > > > example, a developer using the released version of Shark but wanting to > > > pick up the bug fixes in Spark doesn't have a good option anymore since > > > 0.8.1-SNAPSHOT (or the eventual 0.8.1 release) doesn't work, and moving > > to > > > the wild and woolly development on the master branches of Spark and > Shark > > > is not a good idea for someone trying to develop production code. In > > other > > > words, all of the bug fixes in Spark 0.8.1 are not accessible to this > > > developer until such time as there are available 0.8.1-compatible > > versions > > > of Shark and anything else built on Spark that this developer is using. > > > > > > The only other option is trying to cherry-pick commits from, e.g., > Shark > > > 0.9.0-SNAPSHOT into Shark 0.8.0 until Shark 0.8.0 has been brought up > to > > a > > > point where it works with Spark 0.8.1. But an application developer > > > shouldn't need to do that just to get the bug fixes in Spark 0.8.1, and > > it > > > is not immediately obvious just which Shark commits are necessary and > > > sufficient to produce a correct, Spark-0.8.1-compatible version of > Shark > > > (indeed, there is no guarantee that such a thing is even possible.) > > Right > > > now, I believe that 67626ae3eb6a23efc504edf5aedc417197f072cf, > > > 488930f5187264d094810f06f33b5b5a2fde230a and > > > bae19222b3b221946ff870e0cee4dba0371dea04 are necessary to get Shark to > > work > > > with Spark 0.8.1-SNAPSHOT, but that those commits are not sufficient > > (Shark > > > builds against Spark 0.8.1-SNAPSHOT with those cherry-picks, but I'm > > still > > > seeing runtime errors.) > > > > > > In short, this is not a good situation, and we probably need a real 0.8 > > > maintenance branch that maintains backward compatibility with 0.8.0, > > > because (at least to me) the current branch-0.8 of Spark looks more > like > > > another active development branch (in addition to the master and > > scala-2.10 > > > branches) than it does a maintenance branch. > > > > > >
