Merge pull request #5301 from eatkins/classloader-close

Add closeClassLoader setting

main/src/main/java/sbt/internal/BottomClassLoader.java

@@ -32,9 +32,10 @@ final class BottomClassLoader extends ManagedClassLoader {
       final URL[] dynamicClasspath,
       final ReverseLookupClassLoader reverseLookupClassLoader,
       final File tempDir,
+      final boolean close,
       final boolean allowZombies,
       final Logger logger) {
-    super(dynamicClasspath, reverseLookupClassLoader, allowZombies, logger);
+    super(dynamicClasspath, reverseLookupClassLoader, close, allowZombies, logger);
     setTempDir(tempDir);
     this.holder = holder;
     this.parent = reverseLookupClassLoader;

main/src/main/java/sbt/internal/FlatLoader.java

@@ -20,9 +20,10 @@ final class FlatLoader extends ManagedClassLoader {
       final URL[] urls,
       final ClassLoader parent,
       final File file,
+      final boolean close,
       final boolean allowZombies,
       final Logger logger) {
-    super(urls, parent, allowZombies, logger);
+    super(urls, parent, close, allowZombies, logger);
     setTempDir(file);
   }
 

main/src/main/java/sbt/internal/LayeredClassLoader.java

@@ -12,9 +12,9 @@ import java.net.URL;
 import sbt.util.Logger;
 
 final class LayeredClassLoader extends ManagedClassLoader {
-  LayeredClassLoader(final URL[] classpath, final ClassLoader parent, final File tempDir, final
+  LayeredClassLoader(final URL[] classpath, final ClassLoader parent, final File tempDir, final boolean close, final
       boolean allowZombies, final Logger logger) {
-    super(classpath, parent, allowZombies, logger);
+    super(classpath, parent, close, allowZombies, logger);
     setTempDir(tempDir);
   }
 

main/src/main/java/sbt/internal/ManagedClassLoader.java

@@ -20,6 +20,7 @@ abstract class ManagedClassLoader extends URLClassLoader implements NativeLoader
   private final AtomicBoolean closed = new AtomicBoolean(false);
   private final AtomicBoolean printedWarning = new AtomicBoolean(false);
   private final AtomicReference<ZombieClassLoader> zombieLoader = new AtomicReference<>();
+  private final boolean close;
   private final boolean allowZombies;
   private final Logger logger;
   private final NativeLookup nativeLookup = new NativeLookup();
@@ -29,8 +30,9 @@ abstract class ManagedClassLoader extends URLClassLoader implements NativeLoader
   }
 
   ManagedClassLoader(
-      final URL[] urls, final ClassLoader parent, final boolean allowZombies, final Logger logger) {
+      final URL[] urls, final ClassLoader parent, final boolean close, final boolean allowZombies, final Logger logger) {
     super(urls, parent);
+    this.close = close;
     this.allowZombies = allowZombies;
     this.logger = logger;
   }
@@ -103,8 +105,8 @@ abstract class ManagedClassLoader extends URLClassLoader implements NativeLoader
   @Override
   public void close() throws IOException {
     final ZombieClassLoader zb = zombieLoader.getAndSet(null);
-    if (zb != null) zb.close();
+    if (zb != null && close) zb.close();
-    if (closed.compareAndSet(false, true)) super.close();
+    if (close && closed.compareAndSet(false, true)) super.close();
   }
 
   @Override

main/src/main/java/sbt/internal/ReverseLookupClassLoader.java

@@ -36,8 +36,12 @@ import sbt.util.Logger;
  */
 final class ReverseLookupClassLoader extends ManagedClassLoader {
   ReverseLookupClassLoader(
-      final URL[] urls, final ClassLoader parent, final boolean allowZombies, final Logger logger) {
+      final URL[] urls,
-    super(urls, parent, allowZombies, logger);
+      final ClassLoader parent,
+      final boolean close,
+      final boolean allowZombies,
+      final Logger logger) {
+    super(urls, parent, close, allowZombies, logger);
     this.parent = parent;
   }
 

main/src/main/scala/sbt/Defaults.scala

@@ -205,7 +205,8 @@ object Defaults extends BuildCommon {
       bgStop := bgStopTask.evaluated,
       bgWaitFor := bgWaitForTask.evaluated,
       bgCopyClasspath :== true,
-      allowZombieClassLoaders :== !SysProp.closeClassLoaders,
+      closeClassLoaders :== SysProp.closeClassLoaders,
+      allowZombieClassLoaders :== true,
     )
 
   private[sbt] lazy val globalIvyCore: Seq[Setting[_]] =

main/src/main/scala/sbt/Keys.scala

@@ -327,6 +327,7 @@ object Keys {
   val dependencyClasspathAsJars = taskKey[Classpath]("The classpath consisting of internal and external, managed and unmanaged dependencies, all as JARs.")
   val fullClasspathAsJars = taskKey[Classpath]("The exported classpath, consisting of build products and unmanaged and managed, internal and external dependencies, all as JARs.")
   val internalDependencyConfigurations = settingKey[Seq[(ProjectRef, Set[String])]]("The project configurations that this configuration depends on")
+  val closeClassLoaders = settingKey[Boolean]("Close classloaders in run and test when the task completes.").withRank(DSetting)
   val allowZombieClassLoaders = settingKey[Boolean]("Allow a classloader that has previously been closed by `run` or `test` to continue loading classes.")
 
   val useCoursier = settingKey[Boolean]("Use Coursier for dependency resolution.").withRank(BSetting)

main/src/main/scala/sbt/internal/ClassLoaders.scala

@@ -44,6 +44,7 @@ private[sbt] object ClassLoaders {
       else si.libraryJars.map(j => j -> IO.getModifiedTimeOrZero(j)).toSeq ++ rawCP
     val exclude = dependencyJars(exportedProducts).value.toSet ++ si.libraryJars
     val logger = state.value.globalLogging.full
+    val close = closeClassLoaders.value
     val allowZombies = allowZombieClassLoaders.value
     buildLayers(
       strategy = classLoaderLayeringStrategy.value,
@@ -55,6 +56,7 @@ private[sbt] object ClassLoaders {
       tmp = IO.createUniqueDirectory(taskTemporaryDirectory.value),
       scope = resolvedScoped.value.scope,
       logger = logger,
+      close = close,
       allowZombies = allowZombies,
     )
   }
@@ -88,6 +90,7 @@ private[sbt] object ClassLoaders {
         val allDeps = dependencyJars(dependencyClasspath).value.filterNot(exclude)
         val logger = state.value.globalLogging.full
         val allowZombies = allowZombieClassLoaders.value
+        val close = closeClassLoaders.value
         val newLoader =
           (classpath: Seq[File]) => {
             val mappings = classpath.map(f => f.getName -> f).toMap
@@ -102,6 +105,7 @@ private[sbt] object ClassLoaders {
               tmp = taskTemporaryDirectory.value: @sbtUnchecked,
               scope = resolvedScope,
               logger = logger,
+              close = close,
               allowZombies = allowZombies,
             )
           }
@@ -136,11 +140,12 @@ private[sbt] object ClassLoaders {
       tmp: File,
       scope: Scope,
       logger: Logger,
+      close: Boolean,
       allowZombies: Boolean
   ): ClassLoader = {
     val cpFiles = fullCP.map(_._1)
     strategy match {
-      case Flat => new FlatLoader(cpFiles.urls, interfaceLoader, tmp, allowZombies, logger)
+      case Flat => new FlatLoader(cpFiles.urls, interfaceLoader, tmp, close, allowZombies, logger)
       case _ =>
         val layerDependencies = strategy match {
           case _: AllLibraryJars => true
@@ -206,6 +211,7 @@ private[sbt] object ClassLoaders {
                 new ReverseLookupClassLoaderHolder(
                   otherDependencies,
                   frameworkLayer,
+                  close,
                   allowZombies,
                   logger
                 )
@@ -225,7 +231,7 @@ private[sbt] object ClassLoaders {
             cl.getParent match {
               case dl: ReverseLookupClassLoaderHolder => dl.checkout(dynamicClasspath, tmp)
               case _ =>
-                new LayeredClassLoader(dynamicClasspath.urls, cl, tmp, allowZombies, logger)
+                new LayeredClassLoader(dynamicClasspath.urls, cl, tmp, close, allowZombies, logger)
             }
         }
     }

main/src/main/scala/sbt/internal/LayeredClassLoaders.scala

@@ -42,6 +42,7 @@ import scala.collection.JavaConverters._
 private[internal] final class ReverseLookupClassLoaderHolder(
     val classpath: Seq[File],
     val parent: ClassLoader,
+    val closeThis: Boolean,
     val allowZombies: Boolean,
     val logger: Logger
 ) extends URLClassLoader(Array.empty, null) {
@@ -62,7 +63,7 @@ private[internal] final class ReverseLookupClassLoaderHolder(
       throw new IllegalStateException(msg)
     }
     val reverseLookupClassLoader = cached.getAndSet(null) match {
-      case null => new ReverseLookupClassLoader(urls, parent, allowZombies, logger)
+      case null => new ReverseLookupClassLoader(urls, parent, closeThis, allowZombies, logger)
       case c    => c
     }
     reverseLookupClassLoader.setup(tempDir)
@@ -71,6 +72,7 @@ private[internal] final class ReverseLookupClassLoaderHolder(
       dynamicClasspath.map(_.toURI.toURL).toArray,
       reverseLookupClassLoader,
       tempDir,
+      closeThis,
       allowZombies,
       logger
     )

sbt/src/sbt-test/classloader-cache/spark/build.sbt

@@ -5,3 +5,5 @@ version := "1.0"
 scalaVersion := "2.12.10"
 
 libraryDependencies += "org.apache.spark" %% "spark-sql" % "2.4.3"
+
+Compile / closeClassLoaders := false