Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Unexpected type: <nulltype> when both operands of a ternary expression are null #1012

Closed
gavlyukovskiy opened this issue Aug 4, 2024 · 4 comments · Fixed by #1030
Closed

Unexpected type: <nulltype> when both operands of a ternary expression are null #1012

gavlyukovskiy opened this issue Aug 4, 2024 · 4 comments · Fixed by #1030
Labels
bug

Comments

@gavlyukovskiy
Copy link

Without any nullability annotations, compiling this code

public static String foo(String x) {
    return x.isEmpty() ? null : null;
}

gives an error

An exception has occurred in the compiler (22.0.2). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
com.google.common.util.concurrent.ExecutionError: java.lang.AssertionError: unexpected type: <nulltype>

The code compiles fine when either of the operands is not null - x.isEmpty() ? "null" : null or x.isEmpty() ? null : "null".

Similar error can be observed when the expression is inside a lambda function:

Function<String, String> f = x -> x.isEmpty() ? null : null;

Full stacktrace:

An exception has occurred in the compiler (22.0.2). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
com.google.common.util.concurrent.ExecutionError: java.lang.AssertionError: unexpected type: <nulltype>
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2084)
        at com.google.common.cache.LocalCache.get(LocalCache.java:4012)
        at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:4035)
        at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:5011)
        at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:5018)
        at com.uber.nullaway.dataflow.DataFlow.dataflow(DataFlow.java:154)
        at com.uber.nullaway.dataflow.DataFlow.resultFor(DataFlow.java:283)
        at com.uber.nullaway.dataflow.DataFlow.resultForExpr(DataFlow.java:261)
        at com.uber.nullaway.dataflow.DataFlow.expressionDataflow(DataFlow.java:207)
        at com.uber.nullaway.dataflow.AccessPathNullnessAnalysis.getNullness(AccessPathNullnessAnalysis.java:130)
        at com.uber.nullaway.NullAway.nullnessFromDataflow(NullAway.java:2470)
        at com.uber.nullaway.NullAway.mayBeNullExpr(NullAway.java:2448)
        at com.uber.nullaway.NullAway.checkReturnExpression(NullAway.java:937)
        at com.uber.nullaway.NullAway.matchReturn(NullAway.java:379)
        at com.google.errorprone.scanner.ErrorProneScanner.processMatchers(ErrorProneScanner.java:449)
        at com.google.errorprone.scanner.ErrorProneScanner.visitReturn(ErrorProneScanner.java:816)
        at com.google.errorprone.scanner.ErrorProneScanner.visitReturn(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1736)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
        at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:111)
        at jdk.compiler/com.sun.source.util.TreeScanner.visitBlock(TreeScanner.java:272)
        at com.google.errorprone.scanner.ErrorProneScanner.visitBlock(ErrorProneScanner.java:520)
        at com.google.errorprone.scanner.ErrorProneScanner.visitBlock(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1104)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
        at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:96)
        at jdk.compiler/com.sun.source.util.TreeScanner.visitMethod(TreeScanner.java:224)
        at com.google.errorprone.scanner.ErrorProneScanner.visitMethod(ErrorProneScanner.java:740)
        at com.google.errorprone.scanner.ErrorProneScanner.visitMethod(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:948)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
        at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:96)
        at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:111)
        at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:119)
        at jdk.compiler/com.sun.source.util.TreeScanner.visitClass(TreeScanner.java:203)
        at com.google.errorprone.scanner.ErrorProneScanner.visitClass(ErrorProneScanner.java:548)
        at com.google.errorprone.scanner.ErrorProneScanner.visitClass(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:855)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
        at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
        at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:111)
        at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:119)
        at jdk.compiler/com.sun.source.util.TreeScanner.visitCompilationUnit(TreeScanner.java:152)
        at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:560)
        at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:623)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:66)
        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:227)
        at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:133)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1443)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1390)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:963)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)
        at org.gradle.internal.compiler.java.IncrementalCompileTask.call(IncrementalCompileTask.java:92)
        at org.gradle.api.internal.tasks.compile.AnnotationProcessingCompileTask.call(AnnotationProcessingCompileTask.java:94)
        at org.gradle.api.internal.tasks.compile.ResourceCleaningCompilationTask.call(ResourceCleaningCompilationTask.java:57)
        at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:76)
        at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:46)
        at org.gradle.api.internal.tasks.compile.daemon.AbstractIsolatedCompilerWorkerExecutor$CompilerWorkAction.execute(AbstractIsolatedCompilerWorkerExecutor.java:78)
        at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:63)
        at org.gradle.workers.internal.AbstractClassLoaderWorker$1.create(AbstractClassLoaderWorker.java:54)
        at org.gradle.workers.internal.AbstractClassLoaderWorker$1.create(AbstractClassLoaderWorker.java:48)
        at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:100)
        at org.gradle.workers.internal.AbstractClassLoaderWorker.executeInClassLoader(AbstractClassLoaderWorker.java:48)
        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:104)
        at org.gradle.workers.internal.WorkerDaemonServer.run(WorkerDaemonServer.java:73)
        at org.gradle.process.internal.worker.request.WorkerAction$1.call(WorkerAction.java:146)
        at org.gradle.process.internal.worker.child.WorkerLogEventListener.withWorkerLoggingProtocol(WorkerLogEventListener.java:41)
        at org.gradle.process.internal.worker.request.WorkerAction.lambda$run$0(WorkerAction.java:143)
        at org.gradle.internal.operations.CurrentBuildOperationRef.with(CurrentBuildOperationRef.java:85)
        at org.gradle.process.internal.worker.request.WorkerAction.run(WorkerAction.java:135)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
        at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
        at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
        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.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:48)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1570)
Caused by: java.lang.AssertionError: unexpected type: <nulltype>
        at jdk.compiler/com.sun.tools.javac.tree.TreeMaker.Type(TreeMaker.java:883)
        at jdk.compiler/com.sun.tools.javac.tree.TreeMaker.VarDef(TreeMaker.java:905)
        at org.checkerframework.nullaway.javacutil.trees.TreeBuilder.buildVariableDecl(TreeBuilder.java:330)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitConditionalExpression(CFGTranslationPhaseOne.java:2732)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitConditionalExpression(CFGTranslationPhaseOne.java:212)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCConditional.accept(JCTree.java:1548)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.scan(CFGTranslationPhaseOne.java:571)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitReturn(CFGTranslationPhaseOne.java:3511)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitReturn(CFGTranslationPhaseOne.java:212)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1736)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.scan(CFGTranslationPhaseOne.java:571)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitBlock(CFGTranslationPhaseOne.java:2349)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.visitBlock(CFGTranslationPhaseOne.java:212)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1104)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.scan(CFGTranslationPhaseOne.java:571)
        at org.checkerframework.nullaway.dataflow.cfg.builder.CFGTranslationPhaseOne.process(CFGTranslationPhaseOne.java:468)
        at com.uber.nullaway.dataflow.cfg.NullAwayCFGBuilder.build(NullAwayCFGBuilder.java:80)
        at com.uber.nullaway.dataflow.DataFlow$2.load(DataFlow.java:137)
        at com.uber.nullaway.dataflow.DataFlow$2.load(DataFlow.java:102)
        at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3571)
        at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2313)
        at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2190)
        at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2080)
        ... 96 more

Reproducer (branch nulltype): https://github.com/gavlyukovskiy/nullaway-reproducer/tree/nulltype (./gradlew build)

JDK: temurin 22.0.2, also reproducible on 21.0.3 and 17.0.11

Versions:

  • com.google.errorprone:error_prone_core:2.29.2
  • com.uber.nullaway:nullaway:0.11.1
  • net.ltgt.errorprone:4.0.1
@msridhar
Copy link
Collaborator

msridhar commented Aug 4, 2024

Nice find! I will take a look.

@msridhar msridhar mentioned this issue Aug 6, 2024
Closed
@msridhar
Copy link
Collaborator

msridhar commented Aug 7, 2024

This is an upstream issue in Checker Framework: typetools/checker-framework#6743 We will need a fix there and then we can pull in the release with the fix.

I presume this is not hard for you to work around @gavlyukovskiy?

@msridhar msridhar added the bug label Aug 7, 2024
@gavlyukovskiy
Copy link
Author

Thank you for checking @msridhar. The code is pretty much nonsensical, and it is certainly very easy to workaround, just thought that it's worth it to report 🙂

@msridhar
Copy link
Collaborator

Fixed by typetools/checker-framework#6752. We'll get the fix when it reaches a Checker Framework release and we update.

@msridhar msridhar mentioned this issue Sep 4, 2024
Merged
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
bug
Projects
None yet
Milestone
No milestone
Development

Successfully merging a pull request may close this issue.

Update to Checker Framework 3.48.0 uber/NullAway
2 participants
@msridhar @gavlyukovskiy