Explicitly pass built compiler-bridge jar locations from the build system into Mill as JVM properties.

This makes the dependency between the compiler-bridge jar and the Mill executable explicit, allowing us to swap out the locations compiler-bridge jars (which end up in different places, depending on whether you're building with SBT or Mill) or eventually making them load from Maven Central in a "release" Mill executable

Since Mill (and uTest) both do not support SBT-style test arguments, we need to use `forkTest` instead of `test` to run the Mill tests passing the compiler-jar locations as JVM props. This necessitated some fixes to make `forkTest` behave properly

1 files changed, 22 insertions, 2 deletions

diff --git a/core/src/main/scala/mill/modules/Jvm.scala b/core/src/main/scala/mill/modules/Jvm.scala
index 43382b8d..ddc8b427 100644
--- a/core/src/main/scala/mill/modules/Jvm.scala
+++ b/core/src/main/scala/mill/modules/Jvm.scala
@@ -1,6 +1,7 @@
 package mill.modules
 
 import java.io.FileOutputStream
+import java.net.URLClassLoader
 import java.nio.file.attribute.PosixFilePermission
 import java.util.jar.{JarEntry, JarFile, JarOutputStream}
 
@@ -14,16 +15,35 @@ import scala.collection.mutable
 
 
 object Jvm {
-
+  def gatherClassloaderJars(): Seq[Path] = {
+    val allJars = collection.mutable.Buffer.empty[Path]
+    var currentClassloader = Thread.currentThread().getContextClassLoader
+    while(currentClassloader != null){
+      currentClassloader match{
+        case u: URLClassLoader => allJars.appendAll(u.getURLs.map(x => Path(x.getFile)))
+        case _ =>
+      }
+      currentClassloader = currentClassloader.getParent
+    }
+    allJars
+  }
   def subprocess(mainClass: String,
                  classPath: Seq[Path],
+                 jvmOptions: Seq[String] = Seq.empty,
                  options: Seq[String] = Seq.empty,
                  workingDir: Path = ammonite.ops.pwd)
                 (implicit ctx: Ctx) = {
+
+    val commandArgs =
+      Vector("java") ++
+      jvmOptions ++
+      Vector("-cp", classPath.mkString(":"), mainClass) ++
+      options
+
     val proc =
       new java.lang.ProcessBuilder()
         .directory(workingDir.toIO)
-        .command(Vector("java", "-cp", classPath.mkString(":"), mainClass) ++ options:_*)
+        .command(commandArgs:_*)
         .redirectOutput(ProcessBuilder.Redirect.PIPE)
         .redirectError(ProcessBuilder.Redirect.PIPE)
         .start()