Merge pull request scala#13246 from BarkingBad/fix-executable-jars

Fix running JARs from scala script

Author: anatoliykmetyuk

compiler/src/dotty/tools/MainGenericRunner.scala

@@ -12,6 +12,8 @@ import scala.annotation.internal.sharable
 import dotty.tools.dotc.util.ClasspathFromClassloader
 import dotty.tools.runner.ObjectRunner
 import dotty.tools.dotc.config.Properties.envOrNone
+import java.util.jar._
+import java.util.jar.Attributes.Name
 
 enum ExecuteMode:
   case Guess
@@ -31,6 +33,7 @@ case class Settings(
   targetScript: String = "",
   save: Boolean = false,
   modeShouldBeRun: Boolean = false,
+  compiler: Boolean = false,
 ) {
   def withExecuteMode(em: ExecuteMode): Settings = this.executeMode match
     case ExecuteMode.Guess =>
@@ -65,6 +68,9 @@ case class Settings(
 
   def withModeShouldBeRun: Settings =
     this.copy(modeShouldBeRun = true)
+
+  def withCompiler: Settings =
+    this.copy(compiler = true)
 }
 
 object MainGenericRunner {
@@ -97,6 +103,8 @@ object MainGenericRunner {
       )
     case "-save" :: tail =>
       process(tail, settings.withSave)
+    case "-with-compiler" :: tail =>
+      process(tail, settings.withCompiler)
     case (o @ javaOption(striped)) :: tail =>
       process(tail, settings.withJavaArgs(striped).withScalaArgs(o))
     case (o @ scalaOption(_*)) :: tail =>
@@ -128,8 +136,34 @@ object MainGenericRunner {
         repl.Main.main(properArgs.toArray)
       case ExecuteMode.Run =>
         val scalaClasspath = ClasspathFromClassloader(Thread.currentThread().getContextClassLoader).split(classpathSeparator)
-        val newClasspath = (settings.classPath ++ scalaClasspath :+ ".").map(File(_).toURI.toURL)
-        errorFn("", ObjectRunner.runAndCatch(newClasspath, settings.residualArgs.head, settings.residualArgs.drop(1)))
+
+        def removeCompiler(cp: Array[String]) =
+          if (!settings.compiler) then // Let's remove compiler from the classpath
+            val compilerLibs = Seq("scala3-compiler", "scala3-interfaces", "tasty-core", "scala-asm", "scala3-staging", "scala3-tasty-inspector")
+            cp.filterNot(c => compilerLibs.exists(c.contains))
+          else
+            cp
+        val newClasspath = (settings.classPath ++ removeCompiler(scalaClasspath) :+ ".").map(File(_).toURI.toURL)
+
+        val res = ObjectRunner.runAndCatch(newClasspath, settings.residualArgs.head, settings.residualArgs.drop(1)).flatMap {
+          case ex: ClassNotFoundException if ex.getMessage == settings.residualArgs.head =>
+            val file = settings.residualArgs.head
+            def withJarInput[T](f: JarInputStream => T): T =
+              val in = new JarInputStream(java.io.FileInputStream(file))
+              try f(in)
+              finally in.close()
+            val manifest = withJarInput(s => Option(s.getManifest))
+            manifest match
+              case None => Some(IllegalArgumentException(s"Cannot find manifest in jar: $file"))
+              case Some(f) =>
+                f.getMainAttributes.get(Name.MAIN_CLASS) match
+                  case mainClass: String =>
+                    ObjectRunner.runAndCatch(newClasspath :+ File(file).toURI.toURL, mainClass, settings.residualArgs)
+                  case _ =>
+                    Some(IllegalArgumentException(s"No main class defined in manifest in jar: $file"))
+          case ex => Some(ex)
+        }
+        errorFn("", res)
       case ExecuteMode.Script =>
         val properArgs =
           List("-classpath", settings.classPath.mkString(classpathSeparator)).filter(Function.const(settings.classPath.nonEmpty))

compiler/test-coursier/dotty/tools/coursier/CoursierScalaTests.scala

@@ -92,6 +92,12 @@ class CoursierScalaTests:
       assertTrue(source.getParentFile.listFiles.find(_.getName == "myfile.jar").isDefined)
     jar()
 
+    def runThatJar() =
+      val source = new File(getClass.getResource("/run/myfile.jar").getPath)
+      val output = CoursierScalaTests.csCmd(source.absPath)
+      assertEquals(output.mkString("\n"), "Hello")
+    runThatJar()
+
 object CoursierScalaTests:
 
   def execCmd(command: String, options: String*): List[String] =