runClasspath should not include compileModuleDeps classes

[lolgab]

Motivation

I expect compileModuleDeps to be used only at compile time and not at runtime. So at runtime, the other module shouldn't exist in the classpath.

Reproduction

// build.sc
import mill._, scalalib._

object m1 extends JavaModule {
  def compileModuleDeps = Seq(m2)
}
object m2 extends JavaModule

$ mill show m1.runClasspath

[
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/m2/compile-resources",
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/m2/resources",
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/out/m2/compile.dest/classes",
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/m1/compile-resources",
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/m1/resources",
  "ref:v0:c984eca8:/Users/lorenzo/scala/repro-mill/consumer/out/m1/compile.dest/classes"
]

As you can see there are many m2 entries in runClasspath

Mill version

Both 0.11.12 and 0.12.0-RC3

[lefou]

This is with Mill 0.11.12, right?

[lihaoyi]

This appears to be fixed in main, and I bisected the fix down to #3774. Indeed we can see the updates to scalalib/test/src/mill/scalalib/ScalaMultiModuleClasspathsTests.scala reflect the changed semantics with compileModuleDeps no longer being included in the runClasspath

[lefou]

Indeed, I can't reproduce with Mill built from current main branch.

> cat > build.sc << EOF
// build.sc
import mill._, scalalib._

object m1 extends JavaModule {
  def compileModuleDeps = Seq(m2)
}
object m2 extends JavaModule
EOF

> dev-mill show m1.runClasspath
[build.mill-57/61] compile
[build.mill-57] [info] compiling 1 Scala source to /tmp/mill1/out/mill-build/compile.dest/classes ...
[build.mill-57] [info] done compiling
[1/1] show
[
  "ref:v0:c984eca8:/tmp/mill1/m1/compile-resources",
  "ref:v0:c984eca8:/tmp/mill1/m1/resources",
  "ref:v0:c984eca8:/tmp/mill1/out/m1/compile.dest/classes"
]
[57/57] === show m1.runClasspath === 1s