Add tests for patching class file version

Some are currently failing
see raphw/byte-buddy#880

apm-agent-core/pom.xml

@@ -144,6 +144,18 @@
             <version>${version.cucumber}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>3.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-pool2</artifactId>
+            <version>2.6.2</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

apm-agent-core/src/main/java/co/elastic/apm/agent/bci/ElasticApmAgent.java

@@ -451,9 +451,11 @@ public static synchronized void reset() {
         }
         dynamicClassFileTransformers.clear();
         instrumentation = null;
+        HelperClassManager.ForIndyPlugin.clear();
     }
 
-    private static AgentBuilder getAgentBuilder(final ByteBuddy byteBuddy, final CoreConfiguration coreConfiguration, Logger logger, AgentBuilder.DescriptionStrategy descriptionStrategy, boolean premain) {
+    private static AgentBuilder getAgentBuilder(final ByteBuddy byteBuddy, final CoreConfiguration coreConfiguration, final Logger logger,
+                                                final AgentBuilder.DescriptionStrategy descriptionStrategy, final boolean premain) {
         AgentBuilder.LocationStrategy locationStrategy = AgentBuilder.LocationStrategy.ForClassLoader.WEAK;
         if (agentJarFile != null) {
             try {
@@ -475,6 +477,14 @@ private static AgentBuilder getAgentBuilder(final ByteBuddy byteBuddy, final Cor
             // when runtime attaching, only retransform up to 100 classes at once and sleep 100ms in-between as retransformation causes a stop-the-world pause
             .with(premain ? RedefinitionStrategy.BatchAllocator.ForTotal.INSTANCE : RedefinitionStrategy.BatchAllocator.ForFixedSize.ofSize(100))
             .with(premain ? RedefinitionStrategy.Listener.NoOp.INSTANCE : RedefinitionStrategy.Listener.Pausing.of(100, TimeUnit.MILLISECONDS))
+            .with(new RedefinitionStrategy.Listener.Adapter() {
+                @Override
+                public Iterable<? extends List<Class<?>>> onError(int index, List<Class<?>> batch, Throwable throwable, List<Class<?>> types) {
+                    logger.warn("Error while redefining classes {}", throwable.getMessage());
+                    logger.debug(throwable.getMessage(), throwable);
+                    return super.onError(index, batch, throwable, types);
+                }
+            })
             .with(descriptionStrategy)
             .with(locationStrategy)
             .with(new ErrorLoggingListener())

apm-agent-core/src/main/java/co/elastic/apm/agent/bci/HelperClassManager.java

@@ -284,13 +284,17 @@ public static class ForIndyPlugin {
          * Creates an isolated CL that has two parents: the target class loader and the agent CL.
          * The agent class loader is currently the bootstrap CL but in the future it will be an isolated CL that is a child of the bootstrap CL.
          */
-        @Nullable
-        public synchronized static ClassLoader getOrCreatePluginClassLoader(@Nullable ClassLoader targetClassLoader, @Nullable ProtectionDomain protectionDomain, List<String> classesToInject, ElementMatcher<? super TypeDescription> exclusionMatcher) throws Exception {
+        public synchronized static ClassLoader getOrCreatePluginClassLoader(@Nullable ClassLoader targetClassLoader, List<String> classesToInject, ElementMatcher<? super TypeDescription> exclusionMatcher) throws Exception {
             classesToInject = new ArrayList<>(classesToInject);
 
             Map<Collection<String>, WeakReference<ClassLoader>> injectedClasses = getOrCreateInjectedClasses(targetClassLoader);
             if (injectedClasses.containsKey(classesToInject)) {
-                return injectedClasses.get(classesToInject).get();
+                ClassLoader pluginClassLoader = injectedClasses.get(classesToInject).get();
+                if (pluginClassLoader == null) {
+                    injectedClasses.remove(classesToInject);
+                } else {
+                    return pluginClassLoader;
+                }
             }
 
             List<String> classesToInjectCopy = new ArrayList<>(classesToInject.size());
@@ -309,7 +313,6 @@ public synchronized static ClassLoader getOrCreatePluginClassLoader(@Nullable Cl
             ClassLoader pluginClassLoader = new ByteArrayClassLoader.ChildFirst(parent, true, typeDefinitions, ByteArrayClassLoader.PersistenceHandler.MANIFEST);
             injectedClasses.put(classesToInject, new WeakReference<>(pluginClassLoader));
 
-
             return pluginClassLoader;
         }
 

apm-agent-core/src/main/java/co/elastic/apm/agent/bci/IndyBootstrap.java

@@ -236,14 +236,10 @@ public static ConstantCallSite bootstrap(MethodHandles.Lookup lookup,
         }
         ClassLoader pluginClassLoader = HelperClassManager.ForIndyPlugin.getOrCreatePluginClassLoader(
             lookup.lookupClass().getClassLoader(),
-            instrumentedType.getProtectionDomain(),
             pluginClasses,
             isAnnotatedWith(named(GlobalState.class.getName())));
-        if (pluginClassLoader != null) {
-            Class<?> adviceInPluginCL = pluginClassLoader.loadClass(adviceClassName);
-            MethodHandle methodHandle = MethodHandles.lookup().findStatic(adviceInPluginCL, adviceMethodName, adviceMethodType);
-            return new ConstantCallSite(methodHandle);
-        }
-        return null;
+        Class<?> adviceInPluginCL = pluginClassLoader.loadClass(adviceClassName);
+        MethodHandle methodHandle = MethodHandles.lookup().findStatic(adviceInPluginCL, adviceMethodName, adviceMethodType);
+        return new ConstantCallSite(methodHandle);
     }
 }

apm-agent-core/src/main/java/co/elastic/apm/agent/util/PackageScanner.java

@@ -67,11 +67,7 @@ public static List<String> getClassNames(final String basePackage) throws IOExce
                     }
                 }
             } else {
-                final Path basePath = Paths.get(uri);
-                if (basePath.toString().contains("test-classes")) {
-                    continue;
-                }
-                classNames.addAll(listClassNames(basePackage, basePath));
+                classNames.addAll(listClassNames(basePackage, Paths.get(uri)));
             }
         }
         return classNames;