UnusedMethod checker crashes on JDK 17

[TimvdLippe]

Yesterday I received the Dependabot PR for ErrorProne 2.11.0 on Mockito (mockito/mockito#2553) and I have been working on integrating the change. Besides some small breaking changes, everything appears to work fine on JDK 11, but it fails on JDK 17 with the following exception:

     error-prone version: 2.11.0
     BugPattern: UnusedMethod
     Stack Trace:
     java.lang.NoClassDefFoundError: com/sun/tools/javac/util/Filter
  	at com.google.errorprone.bugpatterns.UnusedMethod.fixConstructors(UnusedMethod.java:357)
  	at com.google.errorprone.bugpatterns.UnusedMethod.matchCompilationUnit(UnusedMethod.java:331)
  	at com.google.errorprone.scanner.ErrorProneScanner.processMatchers(ErrorProneScanner.java:449)
  	at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:555)
  	at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:150)
  	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:614)
  	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:60)
  	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:58)
  	at com.google.errorprone.scanner.ErrorProneScannerTransformer.apply(ErrorProneScannerTransformer.java:43)
  	at com.google.errorprone.ErrorProneAnalyzer.finished(ErrorProneAnalyzer.java:152)
  	at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:132)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1394)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1341)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:933)
  	at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
  	at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
  	at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
  	at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)
  	at org.gradle.internal.compiler.java.IncrementalCompileTask.call(IncrementalCompileTask.java:89)
  	at org.gradle.api.internal.tasks.compile.AnnotationProcessingCompileTask.call(AnnotationProcessingCompileTask.java:94)
  	at org.gradle.api.internal.tasks.compile.ResourceCleaningCompilationTask.call(ResourceCleaningCompilationTask.java:57)
  	at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:54)
  	at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:39)
  	at org.gradle.api.internal.tasks.compile.daemon.AbstractDaemonCompiler$CompilerWorkAction.execute(AbstractDaemonCompiler.java:135)
  	at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:63)
  	at org.gradle.workers.internal.AbstractClassLoaderWorker$1.create(AbstractClassLoaderWorker.java:49)
  	at org.gradle.workers.internal.AbstractClassLoaderWorker$1.create(AbstractClassLoaderWorker.java:43)
  	at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:97)
  	at org.gradle.workers.internal.AbstractClassLoaderWorker.executeInClassLoader(AbstractClassLoaderWorker.java:43)
  	at org.gradle.workers.internal.FlatClassLoaderWorker.run(FlatClassLoaderWorker.java:32)
  	at org.gradle.workers.internal.FlatClassLoaderWorker.run(FlatClassLoaderWorker.java:22)
  	at org.gradle.workers.internal.WorkerDaemonServer.run(WorkerDaemonServer.java:85)
  	at org.gradle.workers.internal.WorkerDaemonServer.run(WorkerDaemonServer.java:55)
  	at org.gradle.process.internal.worker.request.WorkerAction$1.call(WorkerAction.java:138)
  	at org.gradle.process.internal.worker.child.WorkerLogEventListener.withWorkerLoggingProtocol(WorkerLogEventListener.java:41)
  	at org.gradle.process.internal.worker.request.WorkerAction.run(WorkerAction.java:135)
  	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
  	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
  	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
  	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
  	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
> Task :compileTestJava
  	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
  	at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:414)
  	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
  	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
  	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
  	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
  	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:61)
  	at java.base/java.lang.Thread.run(Thread.java:833)
  Caused by: java.lang.ClassNotFoundException: com.sun.tools.javac.util.Filter
  	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
  	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587)
  	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)

[tbroyer]

At first glance, looks like these should use ASTHelper.scope(symbol.members()).getSymbols(…):

error-prone/core/src/main/java/com/google/errorprone/bugpatterns/UnusedMethod.java

Lines 356 to 361 in 9e4ca5e

	int constructorCount = size(symbol.members().getSymbols(Symbol::isConstructor));
	int finalFields =
	size(
	symbol
	.members()
	.getSymbols(s -> s.getKind().equals(FIELD) && s.getModifiers().contains(FINAL)));

[cushon]

I think this was a regression in 5e6691c, and I guess we aren't running tests that exercise that line on 17

[tbroyer]

The tests on GitHub run the whole build with the same JDK, so this line will correctly be compiled against the Predicate<…> version of the the method with JDK 17, and the Filter version with JDK 11, so it then runs without problem if/when exercised in tests.
Ideally, compilation would always be done with the same JDK (currently JDK 11 apparently), and tests with a selected JDK. With Maven this could be done with toolchains, or by re-running the build with a different JDK and skipping compilation with -Dmaven.main.skip to reuse the classes from a previous build (or, of course, splitting tests into a separate Maven project so one run can mvn install and the other with a different JDK can only run the test project and consume artifacts from the local repository).
Alternatively, there could probably be a static analysis check (*cough* ErrorProne *cough*) to fail the build if methods that have a specific ASTHelper version are called outside ASTHelper.

[remal]

Guys, can the fix be released?