This issue is being opened in response to this thread.

I want to have reproducible artifacts output from scalac and sbt so that I can:

1. Have multiple, independent CI servers generate a build, sign it, and require multiple signatures for any artifact to be valid later in a pipeline
2. Have independent sources be able to compile and verify that the output JAR / class files are identical to what they compiled locally

Because this could be complicated by faffing about too much with a build.scala like embedding the current time somewhere, let's assume that not all builds will be reproducible and that doing so might require minimal tweaking.

It would be a stretch to require incremental compilation to be reproducible, so what would be sufficient is that any sbt clean compile outputs the exact same things.