Address PR review: optional braces, JProcess for interactive run, workflow comment

- ArgParser: use optional brace / fewer braces style per sbt coding style
- Runner.runJvm: use Java ProcessBuilder with inheritIO() for interactive sbt
- client-test.yml: clarify why sbtw native image is not smoke-tested

.github/workflows/client-test.yml

@@ -96,7 +96,7 @@ jobs:
         # smoke test native Image (sbtn)
         ./client/target/bin/sbtn --sbt-script=$(pwd)/launcher-package/src/universal/bin/sbt.bat about
         ./client/target/bin/sbtn --sbt-script=$(pwd)/launcher-package/src/universal/bin/sbt.bat shutdown
-        # verify sbtw native image was built (do not run: scopt lazy vals break under Graal native image)
+        # verify sbtw native image was built (we do not smoke-test it: scopt uses lazy vals that misbehave under Graal native-image; sbtw is tested as JVM runner below)
         test -f sbtw/target/bin/sbtw.exe || test -f sbtw/target/bin/sbtw
         # test launcher script
         echo build using JDK 17 test using JDK 17 and JDK 25

sbtw/src/main/scala/sbtw/ArgParser.scala

@@ -2,11 +2,11 @@ package sbtw
 
 import scopt.OParser
 
-object ArgParser {
+object ArgParser:
 
-  def parse(args: Array[String]): Option[LauncherOptions] = {
+  def parse(args: Array[String]): Option[LauncherOptions] =
     val b = OParser.builder[LauncherOptions]
-    val parser = {
+    val parser =
       import b.*
       OParser.sequence(
         programName("sbtw"),
@@ -48,10 +48,7 @@ object ArgParser {
           .optional()
           .action((x, c) => c.copy(residual = c.residual :+ x)),
       )
-    }
-    OParser.parse(parser, args, LauncherOptions()).map { opts =>
+    OParser.parse(parser, args, LauncherOptions()).map: opts =>
       val sbtNew = opts.residual.contains("new") || opts.residual.contains("init")
       opts.copy(sbtNew = sbtNew)
-    }
-  }
-}
+end ArgParser

sbtw/src/main/scala/sbtw/Runner.scala

@@ -1,6 +1,7 @@
 package sbtw
 
 import java.io.File
+import java.lang.{ Process as JProcess, ProcessBuilder as JProcessBuilder }
 import scala.sys.process.*
 
 object Runner {
@@ -91,18 +92,22 @@ object Runner {
       sbtJar: String,
       bootArgs: Seq[String],
       verbose: Boolean
-  ): Int = {
+  ): Int =
     val toolOpts =
       sys.env.get("JAVA_TOOL_OPTIONS").toSeq.flatMap(_.split("\\s+").filter(_.nonEmpty))
     val jdkOpts = sys.env.get("JDK_JAVA_OPTIONS").toSeq.flatMap(_.split("\\s+").filter(_.nonEmpty))
     val fullJavaOpts = javaOpts ++ sbtOpts ++ toolOpts ++ jdkOpts
     val cmd = Seq(javaCmd) ++ fullJavaOpts ++ Seq("-cp", sbtJar, "xsbt.boot.Boot") ++ bootArgs
-    if (verbose) {
+    if verbose then
       System.err.println("# Executing command line:")
-      cmd.foreach(a => System.err.println(if (a.contains(" ")) s""""$a"""" else a))
-    }
-    Process(cmd).!
-  }
+      cmd.foreach(a => System.err.println(if a.contains(" ") then s""""$a"""" else a))
+    val jpb = new JProcessBuilder(cmd*)
+    jpb.inheritIO()
+    val p = jpb.start()
+    try
+      p.waitFor()
+      p.exitValue()
+    finally if p.isAlive then p.destroy()
 
   def shutdownAll(javaCmd: String): Int = {
     try {