[BUG] Overlapping source positions for generated code causing Error Prone 2.21.0 to crash

[msridhar]

Describe the bug

When running Error Prone 2.21.0 on a project using Lombok, generated synthetic nodes with overlapping source offsets are causing a crash in Error Prone's NotJavadoc check.

To Reproduce

To repro, check out this branch:

https://github.com/msridhar/NullAway/tree/not-javadoc-lombok-crash-repro

And then run ./gradlew :test-java-lib-lombok:compileJava. When building on either JDK 11 or JDK 17 I get this crash:

NullAway/test-java-lib-lombok/src/main/java/com/uber/lombok/LombokDTO.java:23: error: An unhandled exception was thrown by the Error Prone static analysis plugin.
package com.uber.lombok;
^
     Please report this at https://github.com/google/error-prone/issues/new and include the following:

     error-prone version: 2.21.0
     BugPattern: NotJavadoc
     Stack Trace:
     java.lang.IllegalArgumentException: Overlapping ranges not permitted but found [1233..1241] overlapping [1233..1241]
        at com.google.common.base.Preconditions.checkArgument(Preconditions.java:445)
        at com.google.common.collect.ImmutableRangeSet$Builder.build(ImmutableRangeSet.java:807)
        at com.google.errorprone.bugpatterns.BugChecker.suppressedRegions(BugChecker.java:321)
        at com.google.errorprone.bugpatterns.javadoc.NotJavadoc.matchCompilationUnit(NotJavadoc.java:62)
        at com.google.errorprone.scanner.ErrorProneScanner.processMatchers(ErrorProneScanner.java:449)
        at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:555)
        at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:150)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:591)
        at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:56)
        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:156)
        at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:132)
        [...]

The same crash reproduces with the latest Lombok release, 1.18.28.

Expected behavior

No crash.

Version info (please complete the following information):

• Lombok version 1.18.28
• JDK 11 or 17 javac, Error Prone 2.21.0

Additional context

Reported on the Error Prone issue tracker at google/error-prone#4040. I believe Lombok tries to generate valid source offsets now, so hopefully this can be fixed on the Lombok side.

[Rawi01]

Every generated method/field gets the position of the annotation that triggers the generation. If there are multiple methods they all end up with the same source range. I don't know that there is a better solution for this, if you have one in your mind please let me know.

I think the best solution is to tell error prone to ignore generate stuff.

[msridhar]

Thanks for looking into this. The specific Error Prone crash this was causing got fixed in that checker. I feel like this kind of thing may creep up again in the future, but I don't know how complicated it would be to generate non-overlapping source ranges in these cases, and I don't have a specific suggestion there.