ZipException with compile-only unmanagedClasspath

[Sailsman63]

I'm trying to put together my first mill build, as a test-case for a larger set of projects. The script includes this unmanagedClasspath definition:

def unmanagedClasspath = T {
   Agg.from(os.list(millSourcePath / os.RelPath("../../Baz/Deployment")).map(PathRef(_)))
  }

Yes, that is a (non-mill) project outside of the current directory. Yes, that is intentional. This is the only custom piece of configuration in the build.

When trying to run mill __.assembly I get this output:

foo.upstreamAssembly java.util.zip.ZipException: error in opening zip file
    java.util.zip.ZipFile.open(Native Method)
    java.util.zip.ZipFile.<init>(ZipFile.java:228)
    java.util.zip.ZipFile.<init>(ZipFile.java:157)
    java.util.jar.JarFile.<init>(JarFile.java:171)
    java.util.jar.JarFile.<init>(JarFile.java:135)
    mill.modules.Assembly$.$anonfun$loadShadedClasspath$6(Assembly.scala:107)
    mill.api.AggWrapper$Agg$Mutable.$anonfun$map$1(AggWrapper.scala:68)
    scala.collection.IterableOnceOps.foreach(IterableOnce.scala:563)
    scala.collection.IterableOnceOps.foreach$(IterableOnce.scala:561)
    scala.collection.AbstractIterator.foreach(Iterator.scala:1288)
    mill.api.AggWrapper$Agg$Mutable.map(AggWrapper.scala:68)
    mill.modules.Assembly$.loadShadedClasspath(Assembly.scala:106)
    mill.modules.Jvm$.$anonfun$createAssembly$3(Jvm.scala:369)
    mill.modules.Jvm$.$anonfun$createAssembly$3$adapted(Jvm.scala:357)
    scala.util.Using$.resource(Using.scala:261)
    mill.modules.Jvm$.createAssembly(Jvm.scala:357)
    mill.scalalib.JavaModule.$anonfun$upstreamAssembly$2(JavaModule.scala:312)
    mill.define.ApplyerGenerated.$anonfun$zipMap$1(ApplicativeGenerated.scala:5)
    mill.define.Task$MappedDest.evaluate(Task.scala:396)

If I understand correctly, .assembly is trying to stuff my unmanagedClasspath into the assembled artifacts. That is not the correct thing to do with this build. If I'm right, how do I tell mill that the unmanagedClasspath is compile-time only?

[lefou]

To contribute compile-only artifacts, you can try to add them directly to compileClasspath.

In case these artifacts are suspected to change (which I assumes as this is the outcome of another build process),
I suggest to make it a source target, to properly rebuild when they've changed.

def compileOnlyClasspath = T.sources {
  os.list(millSourcePath / os.up / os.up / "Baz" / "Deployment").map(PathRef(_))
}
def compileClasspath = T{
  super.compileClasspath() ++ compileOnlyClasspath()
}

[Sailsman63]

Thank you!