Error-prone: How to use ErrorProne with Lombok: @Value annotations seem disabled?

[RichardBradley]

Description of the problem / feature request:

I am trying to use ErrorProne and Lombok together.
Various open issues in this repos suggest that this is possible but perhaps difficult or unsupported?

I have found that using ErrorProne seems to entirely disable the "@Value" and "@Data" and similar Lombok annotations, causing compile errors in code that relies on the getters generated by these annoations.

How can I get these two libraries to work together?

Feature requests: what underlying problem are you trying to solve with this feature?

I am trying to use ErrorProne on a codebase that relies on Lombok code-generation annotations.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

I have prepared two simple examples based on the "examples/maven" example in this repos:

The relevant class looks like this:

import lombok.Value;

@Value
public class SomeDataClass {

    public String name;

    @Override
    public String toString() {
        return "SomeDataClass[" + this.getName() + "]";
    }
}

1) Maven and Lombok together: https://github.com/RichardBradley/error-prone/tree/d3ca8c6716a8cde2b2489f5beafa36837acc54e9/examples/maven-with-lombok

This fails to build with the following message:

[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] C:\Work\error-prone\examples\maven-with-lombok\src\main\java\SomeDataClass.java:[11,38] error: cannot find symbol
  symbol: method getName()
[INFO] 1 error

2) The same code, but with ErrorProne disabled: https://github.com/RichardBradley/error-prone/tree/ccadedda3/examples/maven-with-lombok

This builds fine

What version of Error Prone are you using?

Latest master, 976ab7c62771 (2.3.3-SNAPSHOT)

Have you found anything relevant by searching the web?

Related issues:

• #775 : someone using Lombok @Data with ErrorProne, closed as dup
• #751 "Lombok & error-prone dont play together ?": closed as dup (of which?)
• #690: Lombok breaks NestedInstanceOfConditions and InstanceOfAndCastMatchWrongType - closed as fixed?
• #932: seems to be a similar or same question, but was closed without comment

Many thanks,

Rich

[tbroyer]

Lombok needs to be in the processor path. By default, the processor path is the same as the compilation classpath, so adding Lombok as a project dependency is enough. But as soon as your specify it explicitly (through <annotationProcessorPaths> in Maven), you need to add to it everything that needs to be there, and that includes Lombok.

Specifically, you need to add it as a project dependency so you can use the annotations, and in the <annotationProcessorPaths> so that it can process them (and do its dark magic generating code where it's not supposed to)

[RichardBradley]

Thanks, that's very helpful. I have created PRs with suggested doc improvements to help users with similar issues in the future.

I am now getting "Compilation Failure" with no error info from Maven, but I will keep digging.

[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ errorprone-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 3 source files to C:\Work\error-prone\examples\maven-with-lombok\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.907 s
[INFO] Finished at: 2018-11-23T14:38:20Z
[INFO] Final Memory: 24M/981M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project errorprone-example: Compilation failure -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
{

Repro at: https://github.com/RichardBradley/error-prone/tree/00df8f2a7/examples/maven-with-lombok

I am using javac 1.8.0_151 on Windows 10 x64

[RichardBradley]

I have attempted to run javac using the args passed to it by Maven (determined using mvn -X compile) in the above repro case and I get this output:

A plugin threw an uncaught exception.
Consult the following stack trace for details.
java.lang.NoSuchMethodError: com.sun.tools.javac.util.JavacMessages.add(Lcom/sun/tools/javac/util/JavacMessages$ResourceBundleHelper;)V
        at com.google.errorprone.BaseErrorProneJavaCompiler.setupMessageBundle(BaseErrorProneJavaCompiler.java:202)
        at com.google.errorprone.ErrorProneJavacPlugin.init(ErrorProneJavacPlugin.java:40)
        at com.sun.tools.javac.main.Main.compile(Main.java:470)
        at com.sun.tools.javac.main.Main.compile(Main.java:381)
        at com.sun.tools.javac.main.Main.compile(Main.java:370)
        at com.sun.tools.javac.main.Main.compile(Main.java:361)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)

Rather strangely, it seems that the "-J-Xbootclasspath/p:..." arg is not printed by maven -X compile. It is not clear to me whether Maven is not passing this arg or if it is passing it but hiding it from the debug output somehow.

If I retry and manually add that arg, then I get this error from javac:

An annotation processor threw an uncaught exception.
Consult the following stack trace for details.
java.lang.NoClassDefFoundError: com/sun/tools/javac/file/BaseFileObject
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:642)
        at lombok.launch.ShadowClassLoader.loadClass(ShadowClassLoader.java:448)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at lombok.javac.apt.LombokFileObjects$Compiler$2.wrap(LombokFileObjects.java:60)
        at lombok.javac.apt.LombokFileObjects.createEmpty(LombokFileObjects.java:109)
        at lombok.javac.apt.InterceptingJavaFileManager.getJavaFileForOutput(InterceptingJavaFileManager.java:47)
        at com.sun.tools.javac.processing.JavacFiler.createSourceOrClassFile(JavacFiler.java:499)
        at com.sun.tools.javac.processing.JavacFiler.createSourceFile(JavacFiler.java:425)
        at lombok.javac.apt.LombokProcessor.forceNewRound(LombokProcessor.java:289)
        at lombok.javac.apt.LombokProcessor.process(LombokProcessor.java:278)
        at lombok.core.AnnotationProcessor$JavacDescriptor.process(AnnotationProcessor.java:114)
        at lombok.core.AnnotationProcessor.process(AnnotationProcessor.java:164)
        at lombok.launch.AnnotationProcessorHider$AnnotationProcessor.process(AnnotationProcessor.java:59)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:968)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:884)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$2200(JavacProcessingEnvironment.java:108)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1206)
        at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1315)
        at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1246)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:922)
        at com.sun.tools.javac.main.Main.compile(Main.java:302)
        at com.sun.tools.javac.main.Main.compile(Main.java:162)
        at com.sun.tools.javac.Main.compile(Main.java:57)
        at com.sun.tools.javac.Main.main(Main.java:43)
Caused by: java.lang.ClassNotFoundException: com.sun.tools.javac.file.BaseFileObject
        at java.lang.ClassLoader.findClass(ClassLoader.java:530)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at lombok.launch.ShadowClassLoader.loadClass(ShadowClassLoader.java:418)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        ... 26 more

(and indeed, that file does not exist in javac-9+181-r4173-1.jar)

It looks like Lombok 1.16.10 expects a version of javac which is incompatible with the javac provided by ErrorProne? Any ideas how I can fix?

[tbroyer]

It works if you update Lombok to 1.18.4.

[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ errorprone-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 3 source files to /tmp/error-prone/examples/maven-with-lombok/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /tmp/error-prone/examples/maven-with-lombok/src/main/java/Main.java:[20,4] error: [DeadException] Exception created but not thrown
    (see https://errorprone.info/bugpattern/DeadException)
  Did you mean 'throw new RuntimeException();'?
[ERROR] /tmp/error-prone/examples/maven-with-lombok/src/main/java/SomethingElse.java:[19,44] error: [GetClassOnClass] Calling getClass() on an object of type Class returns the Class object for java.lang.Class; you probably meant to operate on the object directly
    (see https://errorprone.info/bugpattern/GetClassOnClass)
  Did you mean 'System.out.println(String.class.toString());' or 'System.out.println(Class.class.toString());'?
[INFO] 2 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.734 s
[INFO] Finished at: 2018-11-23T15:58:38+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project errorprone-example: Compilation failure: Compilation failure: 
[ERROR] /tmp/error-prone/examples/maven-with-lombok/src/main/java/Main.java:[20,4] error: [DeadException] Exception created but not thrown
[ERROR]     (see https://errorprone.info/bugpattern/DeadException)
[ERROR]   Did you mean 'throw new RuntimeException();'?
[ERROR] /tmp/error-prone/examples/maven-with-lombok/src/main/java/SomethingElse.java:[19,44] error: [GetClassOnClass] Calling getClass() on an object of type Class returns the Class object for java.lang.Class; you probably meant to operate on the object directly
[ERROR]     (see https://errorprone.info/bugpattern/GetClassOnClass)
[ERROR]   Did you mean 'System.out.println(String.class.toString());' or 'System.out.println(Class.class.toString());'?
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

[RichardBradley]

Yep, that works for me.

Thanks very much for your help!