Add using directive to vulpix for javac options

Author: hamzaremmal

compiler/test/dotty/tools/utils.scala

@@ -81,7 +81,14 @@ def toolArgsFor(tool: ToolName, filename: Option[String])(lines: List[String]):
 // groups are (name, args)
 // note: ideally we would replace everything that requires this to use directive syntax, however scalajs: --skip has no directive equivalent yet.
 private val toolArg = raw"(?://|/\*| \*) ?(?i:(${ToolName.values.mkString("|")})):((?:[^*]|\*(?!/))*)".r.unanchored
+
+// ================================================================================================
+// =================================== VULPIX DIRECTIVES ==========================================
+// ================================================================================================
+
+/** Directive to specify to vulpix the options to pass to Dotty */
 private val directiveOptionsArg = raw"//> using options (.*)".r.unanchored
+private val directiveJavacOptions = raw"//> using javacOpt (.*)".r.unanchored
 
 // Inspect the lines for compiler options of the form
 // `//> using options args`, `// scalajs: args`, `/* scalajs: args`, ` * scalajs: args` etc.
@@ -90,10 +97,15 @@ private val directiveOptionsArg = raw"//> using options (.*)".r.unanchored
 def toolArgsParse(lines: List[String], filename: Option[String]): List[(String,String)] =
   lines.flatMap {
     case toolArg("scalac", _) => sys.error(s"`// scalac: args` not supported. Please use `//> using options args`${filename.fold("")(f => s" in file $f")}")
+    case toolArg("javac", _) => sys.error(s"`// javac: args` not supported. Please use `//> using javacOpt args`${filename.fold("")(f => s" in file $f")}")
     case toolArg(name, args) => List((name, args))
     case _ => Nil
   } ++
-  lines.flatMap { case directiveOptionsArg(args) => List(("scalac", args)) case _ => Nil }
+  lines.flatMap { 
+    case directiveOptionsArg(args) => List(("scalac", args))
+    case directiveJavacOptions(args) => List(("javac", args))
+    case _ => Nil 
+  }
 
 import org.junit.Test
 import org.junit.Assert._

compiler/test/dotty/tools/vulpix/ParallelTesting.scala

@@ -498,6 +498,7 @@ trait ParallelTesting extends RunnerOrchestration { self =>
         case None => true
 
       def scalacOptions = toolArgs.getOrElse(ToolName.Scalac, Nil)
+      def javacOptions  = toolArgs.getOrElse(ToolName.Javac, Nil)
 
       val flags = flags0
         .and(scalacOptions*)
@@ -512,11 +513,10 @@ trait ParallelTesting extends RunnerOrchestration { self =>
 
       def compileWithJavac(fs: Array[String]) = if (fs.nonEmpty) {
         val fullArgs = Array(
-          "javac",
           "-encoding", StandardCharsets.UTF_8.name,
-        ) ++ flags.javacFlags ++ fs
+        ) ++ flags.javacFlags ++ javacOptions++ fs
 
-        val process = Runtime.getRuntime.exec(fullArgs)
+        val process = Runtime.getRuntime.exec("javac" +: fullArgs)
         val output = Source.fromInputStream(process.getErrorStream).mkString
 
         if waitForJudiciously(process) != 0 then Some(output)