sbt-assembly and multiple class defs in dependencies

Question

Being new to sbt and the sbt-assembly plugin I am confused about how one deals with builds involving different class definitions within dependencies I am trying to package.

[error] (*:assembly) deduplicate: different file contents found in the following:
[error] /Users/dm/.ivy2/cache/org.apache.tika/tika-app/jars/tika-app-1.3.jar:javax/xml/XMLConstants.class
[error] /Users/dm/.ivy2/cache/stax/stax-api/jars/stax-api-1.0.1.jar:javax/xml/XMLConstants.class
[error] /Users/dm/.ivy2/cache/xml-apis/xml-apis/jars/xml-apis-1.3.03.jar:javax/xml/XMLConstants.class

I've added:

mergeStrategy in assembly <<= (mergeStrategy in assembly) { (old) =>
  {
    case PathList("javax", "xml", xs @ _*) => MergeStrategy.first
  }
}

to my build.sbt file, but I'm still getting the error above (regardless of whether or not it's in the build file). Any guidance would be greatly appreciated.

Thanks,

Don

Answer 1

I think you're close. Make sure that you add any rewiring after assemblySettings are loaded, and also pass any patterns you're not handling to the default strategy:

assemblySettings

mergeStrategy in assembly <<= (mergeStrategy in assembly) { (old) =>
  {
    case PathList("javax", "xml", xs @ _*) => MergeStrategy.first
    case _ => old
  }
}

Answer 2

Just an update—with current sbt (0.13.8) and sbt-assembly (0.13.0) versions, Eugene's code becomes:

assemblyMergeStrategy in assembly := {
  case PathList("javax", "xml", xs @ _*) => MergeStrategy.first
  case x =>
    val oldStrategy = (assemblyMergeStrategy in assembly).value
    oldStrategy(x)
}