Hey All, Some people may have noticed PR failures due to binary compatibility checks. We've had these enabled in several of the sub-modules since the 0.9.0 release but we've turned them on in Spark core post 1.0.0 which has much higher churn.
The checks are based on the "migration manager" tool from Typesafe. One issue is that tool doesn't support package-private declarations of classes or methods. Prashant Sharma has built instrumentation that adds partial support for package-privacy (via a workaround) but since there isn't really native support for this in MIMA we are still finding cases in which we trigger false positives. In the next week or two we'll make it a priority to handle more of these false-positive cases. In the mean time users can add manual excludes to: project/MimaExcludes.scala to avoid triggering warnings for certain issues. This is definitely annoying - sorry about that. Unfortunately we are the first open source Scala project to ever do this, so we are dealing with uncharted territory. Longer term I'd actually like to see us just write our own sbt-based tool to do this in a better way (we've had trouble trying to extend MIMA itself, it e.g. has copy-pasted code in it from an old version of the scala compiler). If someone in the community is a Scala fan and wants to take that on, I'm happy to give more details. - Patrick
