It'd be useful to be able to support 'reproducible' builds from sbt/zinc (in the https://reproducible-builds.org/ sense).

One current source of nondeterminism in generated artifacts is the fact that JarOutputStream and ZipOutputStream from java.util are used in IO.jar(), which will include timestamps in the generated jar file. Also I'm not sure the ordering of the files in the archive is deterministic.

There's generally 2 ways to make builds reproducible: generating the assets in a deterministic way, or post-processing them. I'd say generating the jars in a deterministic way would be the nicest approach and make it easiest to integrate into an sbt project.

What would be a good place for extension points so this behavior can be overridden to be deterministic? Or would it even be acceptable to make this the default behavior?