Hi all, As we are getting closer to releasing Flink-1.3, I would like to open a discussion on how far back we provide backwards compatibility for.
The reason for opening the discussion is that i) for the users and for the adoption of the project, it is good to have an explicitely stated policy that implies certain guarantees, and ii) keeping code and tests for backwards compatibility with Flink-1.1 does not offer much. On the contrary, I think that it leads to: 1) dead or ugly code in the codebase, e.g. deprecated class fields that could go away and ugly if() loops (see aligned window operators that were deprecated in 1.2 and are now normal windows), etc 2) expensive tests (as, normally, they read from a savepoint) 3) binary files in the codebase for holding the aforementioned savepoints My proposal for such a policy would be to offer backwards compatibility for one previous version. This means that 1.3 will be compatible with 1.2 (not 1.1). This still allows a clear "backwards compatibility" path when jumping versions (a user that goes from 1.1 to 1.3 can go initially 1.1 -> 1.2, take a savepoint, and then 1.2 -> 1.3), while also allowing us to clean up the codebase a bit. What do you think? Kostas
