Merge pull request #8303 from eed3si9n/wip/jdk25-main

[1.x] Support JDK 25 JEP-512/JEP-445 Main run

.github/workflows/ci.yml

@@ -21,8 +21,8 @@ jobs:
             distribution: temurin
             jobtype: 2
           - os: ubuntu-latest
-            java: 21
-            distribution: temurin
+            java: 25
+            distribution: zulu
             jobtype: 3
           - os: ubuntu-latest
             java: 21

internal/util-collection/src/main/scala/sbt/internal/util/Util.scala

@@ -14,7 +14,7 @@ import java.util.Locale
 import scala.reflect.macros.blackbox
 import scala.language.experimental.macros
 import scala.language.reflectiveCalls
-import scala.util.control.NonFatal
+import scala.util.Properties
 
 object Util {
   def makeList[T](size: Int, value: T): List[T] = List.fill(size)(value)
@@ -88,17 +88,7 @@ object Util {
   def reduceIntents[A1, A2](intents: PartialFunction[A1, A2]*): PartialFunction[A1, A2] =
     intents.toList.reduceLeft(_ orElse _)
 
-  lazy val majorJavaVersion: Int =
-    try {
-      val javaVersion = sys.props.get("java.version").getOrElse("1.0")
-      if (javaVersion.startsWith("1.")) {
-        javaVersion.split("\\.")(1).toInt
-      } else {
-        javaVersion.split("\\.")(0).toInt
-      }
-    } catch {
-      case NonFatal(_) => 0
-    }
+  lazy val isJava19Plus: Boolean = Properties.isJavaAtLeast("19")
 
   private type GetId = {
     def getId: Long
@@ -113,7 +103,7 @@ object Util {
    * https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/Thread.html#threadId()
    */
   def threadId: Long =
-    if (majorJavaVersion < 19) {
+    if (!isJava19Plus) {
       (Thread.currentThread(): AnyRef) match {
         case g: GetId @unchecked => g.getId
       }

project/Dependencies.scala

@@ -15,7 +15,7 @@ object Dependencies {
   private val ioVersion = nightlyVersion.getOrElse("1.10.5")
   private val lmVersion =
     sys.props.get("sbt.build.lm.version").orElse(nightlyVersion).getOrElse("1.11.5")
-  val zincVersion = nightlyVersion.getOrElse("1.10.8")
+  val zincVersion = nightlyVersion.getOrElse("1.11.0")
 
   private val sbtIO = "org.scala-sbt" %% "io" % ioVersion
 

run/src/main/scala/sbt/Run.scala

@@ -19,7 +19,7 @@ import sbt.util.Logger
 
 import scala.sys.process.Process
 import scala.util.control.NonFatal
-import scala.util.{ Failure, Success, Try }
+import scala.util.{ Failure, Properties, Success, Try }
 
 sealed trait ScalaRun {
   def run(mainClass: String, classpath: Seq[File], options: Seq[String], log: Logger): Try[Unit]
@@ -81,7 +81,7 @@ class Run(private[sbt] val newLoader: Seq[File] => ClassLoader, trapExit: Boolea
     def execute(): Unit =
       try {
         log.debug("  Classpath:\n\t" + classpath.mkString("\n\t"))
-        val main = getMainMethod(mainClass, loader)
+        val main = detectMainMethod(mainClass, loader)
         invokeMain(loader, main, options)
       } catch {
         case e: java.lang.reflect.InvocationTargetException =>
@@ -125,14 +125,22 @@ class Run(private[sbt] val newLoader: Seq[File] => ClassLoader, trapExit: Boolea
   }
   private def invokeMain(
       loader: ClassLoader,
-      main: Method,
+      main: DetectedMain,
       options: Seq[String]
   ): Unit = {
     val currentThread = Thread.currentThread
     val oldLoader = Thread.currentThread.getContextClassLoader
     currentThread.setContextClassLoader(loader)
     try {
-      main.invoke(null, options.toArray[String]); ()
+      if (main.isStatic) {
+        if (main.parameterCount > 0) main.method.invoke(null, options.toArray[String])
+        else main.method.invoke(null)
+      } else {
+        val ref = main.mainClass.getDeclaredConstructor().newInstance().asInstanceOf[AnyRef]
+        if (main.parameterCount > 0) main.method.invoke(ref, options.toArray[String])
+        else main.method.invoke(ref)
+      }
+      ()
     } catch {
       case t: Throwable =>
         t.getCause match {
@@ -148,8 +156,21 @@ class Run(private[sbt] val newLoader: Seq[File] => ClassLoader, trapExit: Boolea
       currentThread.setContextClassLoader(oldLoader)
     }
   }
-  def getMainMethod(mainClassName: String, loader: ClassLoader) = {
+  def getMainMethod(mainClassName: String, loader: ClassLoader): Method =
+    detectMainMethod(mainClassName, loader).method
+
+  private def detectMainMethod(mainClassName: String, loader: ClassLoader) = {
     val mainClass = Class.forName(mainClassName, true, loader)
+    if (Run.isJava25Plus) {
+      val method = try {
+        mainClass.getMethod("main", classOf[Array[String]])
+      } catch {
+        case _: NoSuchMethodException => mainClass.getMethod("main")
+      }
+      method.setAccessible(true)
+      val modifiers = method.getModifiers
+      DetectedMain(mainClass, method, isStatic(modifiers), method.getParameterCount())
+    } else {
       val method = mainClass.getMethod("main", classOf[Array[String]])
       // jvm allows the actual main class to be non-public and to run a method in the non-public class,
       //  we need to make it accessible
@@ -159,8 +180,15 @@ class Run(private[sbt] val newLoader: Seq[File] => ClassLoader, trapExit: Boolea
         throw new NoSuchMethodException(mainClassName + ".main is not public")
       if (!isStatic(modifiers))
         throw new NoSuchMethodException(mainClassName + ".main is not static")
-    method
+      DetectedMain(mainClass, method, isStatic = true, method.getParameterCount())
     }
+  }
+  private case class DetectedMain(
+      mainClass: Class[?],
+      method: Method,
+      isStatic: Boolean,
+      parameterCount: Int
+  )
 }
 
 /** This module is an interface to starting the scala interpreter or runner.*/
@@ -195,4 +223,6 @@ object Run {
           s"""nonzero exit code returned from $label: $exitCode""".stripMargin
         )
       )
+
+  private[sbt] lazy val isJava25Plus: Boolean = Properties.isJavaAtLeast("25")
 }

sbt-app/src/sbt-test/run/jep-512/A.scala

@@ -0,0 +1,7 @@
+package example
+
+class A {
+  def main(): Unit = {
+    println("hi")
+  }
+}

sbt-app/src/sbt-test/run/jep-512/build.sbt

@@ -0,0 +1,11 @@
+// 2.12.x uses Zinc's compiler bridge
+ThisBuild / scalaVersion := "2.12.20"
+
+@transient
+lazy val check = taskKey[Unit]("")
+
+check := {
+  if (scala.util.Properties.isJavaAtLeast("25"))
+    (Compile / run).toTask(" ").value
+  else ()
+}

sbt-app/src/sbt-test/run/jep-512/test

@@ -0,0 +1,2 @@
+# > run
+> check