Fix Windows launcher

build.sc

@@ -620,27 +620,13 @@ object dev extends MillModule{
       )
     ).distinct
 
-
-  // Pass dev.assembly VM options via file in Windows due to small max args limit
-  def windowsVmOptions(taskName: String, batch: os.Path, args: Seq[String])
-                      (implicit ctx: mill.util.Ctx) = {
-    if (System.getProperty("java.specification.version").startsWith("1.")) {
-      throw new Error(s"$taskName in Windows is only supported using Java 9 or above")
-    }
-    val vmOptionsFile = T.ctx.dest / "mill.vmoptions"
-    T.ctx.log.info(s"Generated $vmOptionsFile; it should be kept in the same directory as $taskName's ${batch.last}")
-    os.write(vmOptionsFile, args.mkString("\r\n"))
-  }
-
   def launcher = T{
     val isWin = scala.util.Properties.isWin
     val outputPath = T.ctx.dest / (if (isWin) "run.bat" else "run")
 
     os.write(outputPath, prependShellScript())
 
-    if (isWin) {
-      windowsVmOptions("dev.launcher", outputPath, forkArgs())
-    } else {
+    if (!isWin) {
       os.perms.set(outputPath, "rwxrwxrwx")
     }
     PathRef(outputPath)
@@ -650,30 +636,43 @@ object dev extends MillModule{
     val isWin = scala.util.Properties.isWin
     val millPath = T.ctx.dest / (if (isWin) "mill.bat" else "mill")
     os.move(super.assembly().path, millPath)
-    if (isWin) windowsVmOptions("dev.launcher", millPath, forkArgs())
     PathRef(millPath)
   }
 
   def prependShellScript = T{
+    val (millArgs, otherArgs) = forkArgs().partition(arg => arg.startsWith("-DMILL") && !arg.startsWith("-DMILL_VERSION"))
+    // Pass Mill options via file, due to small max args limit in Windows
+    val vmOptionsFile = T.ctx.dest / "mill.properties"
+    val millOptionsContent = millArgs.map(_.drop(2).replace("\\", "/")).mkString("\r\n") // drop -D prefix, replace \ with /
+    os.write(vmOptionsFile, millOptionsContent)
+    val jvmArgs = otherArgs ++ List(s"-DMILL_OPTIONS_PATH=$vmOptionsFile")
     val classpath = runClasspath().map(_.path.toString)
-    val args = forkArgs()
-    val (shellArgs, cmdArgs) =
-      if (!scala.util.Properties.isWin) (
-        args,
-        args
-      )
-      else (
-        Seq("""-XX:VMOptionsFile="$( dirname "$0" )"/mill.vmoptions"""),
-        Seq("""-XX:VMOptionsFile=%~dp0\mill.vmoptions""")
-      )
     launcherScript(
-      shellArgs,
-      cmdArgs,
+      jvmArgs,
+      jvmArgs,
       classpath,
-      classpath
+      Agg(pathingJar().path.toString) // TODO not working yet on Windows! see #791
     )
   }
 
+  def pathingJar = T{
+    // see http://todayguesswhat.blogspot.com/2011/03/jar-manifestmf-class-path-referencing.html
+    // for more detailed explanation
+    val isWin = scala.util.Properties.isWin
+    val classpath = runClasspath().map{ pathRef =>
+      val path = if (isWin) "/" + pathRef.path.toString.replace("\\", "/") 
+                 else pathRef.path.toString
+      if (path.endsWith(".jar")) path
+      else path + "/"
+    }.mkString(" ")
+    val manifestEntries = Map[String,String](
+        java.util.jar.Attributes.Name.MANIFEST_VERSION.toString -> "1.0",
+        "Created-By" -> "Scala mill",
+        "Class-Path" -> classpath
+      )
+    mill.modules.Jvm.createJar(Agg(), mill.modules.Jvm.JarManifest(manifestEntries))
+  }
+
   def run(args: String*) = T.command{
     args match{
       case Nil => mill.eval.Result.Failure("Need to pass in cwd as first argument to dev.run")
@@ -691,7 +690,6 @@ object dev extends MillModule{
   }
 }
 
-
 def assembly = T{
 
   val version = publishVersion()._2

contrib/bsp/src/mill/contrib/BSP.scala

@@ -69,7 +69,7 @@ object BSP extends ExternalModule {
 
   // creates a Json with the BSP connection details
   def createBspConnectionJson(): String = {
-    val millPath = scala.sys.props.get("MILL_CLASSPATH").getOrElse(System.getProperty("MILL_CLASSPATH"))
+    val millPath = Option(mill.modules.Util.millProperty("MILL_CLASSPATH")).getOrElse(System.getProperty("MILL_CLASSPATH"))
     val millVersion = scala.sys.props.get("MILL_VERSION").getOrElse(System.getProperty("MILL_VERSION"))
     write(BspConfigJson("mill-bsp",
                         List(whichJava,

main/client/src/mill/main/client/MillClientMain.java

@@ -19,32 +19,43 @@ public class MillClientMain {
 	public static final int ExitServerCodeWhenVersionMismatch() { return 101; }
 
     static void initServer(String lockBase, boolean setJnaNoSys) throws IOException,URISyntaxException{
-        String[] selfJars = System.getProperty("MILL_CLASSPATH").split(",");
-
-        List<String> l = new ArrayList<>();
+
+        String selfJars = "";
         List<String> vmOptions = new ArrayList<>();
-        l.add(System.getProperty("java.home") + File.separator + "bin" + File.separator + "java");
-        final Properties props = System.getProperties();
-        for(final String k: props.stringPropertyNames()){
+        String millOptionsPath = System.getProperty("MILL_OPTIONS_PATH");
+        if(millOptionsPath != null) {
+            // read MILL_CLASSPATH from file MILL_OPTIONS_PATH
+            Properties millProps = new Properties();
+            millProps.load(new FileInputStream(millOptionsPath));
+            for(final String k: millProps.stringPropertyNames()){
+                String propValue = millProps.getProperty(k);
+                if("MILL_CLASSPATH".equals(k)){
+                    selfJars = propValue;
+                }
+            }
+        } else {
+            // read MILL_CLASSPATH from file sys props
+            selfJars = System.getProperty("MILL_CLASSPATH");
+        }
+
+        final Properties sysProps = System.getProperties();
+        for(final String k: sysProps.stringPropertyNames()){
             if (k.startsWith("MILL_") && !"MILL_CLASSPATH".equals(k)) {
-                vmOptions.add("-D" + k + "=" + props.getProperty(k));
+                vmOptions.add("-D" + k + "=" + sysProps.getProperty(k));
             }
         }
+        if(selfJars == null || selfJars.trim().isEmpty()) {
+            throw new RuntimeException("MILL_CLASSPATH is empty!");
+        }
         if (setJnaNoSys) {
             vmOptions.add("-Djna.nosys=true");
         }
-        if(!Util.isWindows){
-            l.addAll(vmOptions);
-        } else {
-            final File vmOptionsFile = new File(lockBase, "vmoptions");
-            try (PrintWriter out = new PrintWriter(vmOptionsFile)) {
-                for(String opt: vmOptions)
-                out.println(opt);
-            }
-            l.add("-XX:VMOptionsFile=" + vmOptionsFile.getCanonicalPath());
-        }
+
+        List<String> l = new ArrayList<>();
+        l.add(System.getProperty("java.home") + File.separator + "bin" + File.separator + "java");
+        l.addAll(vmOptions);
         l.add("-cp");
-        l.add(String.join(File.pathSeparator, selfJars));
+        l.add(String.join(File.pathSeparator, selfJars.split(",")));
         l.add("mill.main.MillServerMain");
         l.add(lockBase);
 

main/src/modules/Jvm.scala

@@ -347,8 +347,10 @@ object Jvm {
       Seq(
         "",
         ":BOF",
+        "setlocal",
         "@echo off",
         cmdCommands.replaceAll("\r\n|\n", "\r\n"),
+        "endlocal",
         "exit /B %errorlevel%",
         ""
       ).mkString("\r\n")

main/src/modules/Util.scala

@@ -8,6 +8,15 @@ import mill.api.Loose
 
 
 object Util {
+
+  private val LongMillProps = new java.util.Properties()
+
+  {
+    val millOptionsPath = sys.props("MILL_OPTIONS_PATH")
+    if(millOptionsPath != null) 
+      LongMillProps.load(new java.io.FileInputStream(millOptionsPath))
+  }
+
   def cleanupScaladoc(v: String) = {
     v.linesIterator.map(
       _.dropWhile(_.isWhitespace)
@@ -55,7 +64,7 @@ object Util {
                         repositories: Seq[Repository],
                         resolveFilter: os.Path => Boolean = _ => true,
                         artifactSuffix: String = "_2.12") = {
-    val localPath = sys.props(key)
+    val localPath = millProperty(key)
     if (localPath != null) {
       mill.api.Result.Success(
         mill.api.Loose.Agg.from(localPath.split(',').map(p => PathRef(os.Path(p), quick = true)))
@@ -66,11 +75,17 @@ object Util {
         Seq(
           coursier.Dependency(
             coursier.Module(coursier.Organization("com.lihaoyi"), coursier.ModuleName(artifact + artifactSuffix)),
-            sys.props("MILL_VERSION")
+            millProperty("MILL_VERSION")
           )
         ),
         Nil
       ).map(_.filter(x => resolveFilter(x.path)))
     }
   }
+
+  def millProperty(key: String): String = {
+    val sysPropValue = sys.props(key)
+    if(sysPropValue != null) sysPropValue // system property has priority
+    else LongMillProps.getProperty(key)
+  }
 }

scalalib/src/GenIdeaImpl.scala

@@ -73,7 +73,7 @@ case class GenIdeaImpl(evaluator: Evaluator,
 
     val buildLibraryPaths: immutable.Seq[Path] =
       if (!fetchMillModules) Nil
-      else sys.props.get("MILL_BUILD_LIBRARIES") match {
+      else Option(mill.modules.Util.millProperty("MILL_BUILD_LIBRARIES")) match {
         case Some(found) => found.split(',').map(os.Path(_)).distinct.toList
         case None =>
           val repos = modules.foldLeft(Set.empty[Repository]) { _ ++ _._2.repositories } ++ Set(LocalRepositories.ivy2Local, Repositories.central)