StackOverflow in derivingConfig when @Data annotation is used

[etherandrius]

Issue

Code that overflows here

  private Stream<Function<DeriveConfig, DeriveConfig>> deriveConfigs(TypeElement typeElement, Element element,
      HashSet<AnnotationMirror> seenAnnotations) {
    return element.getAnnotationMirrors().stream().sequential().filter(a -> !seenAnnotations.contains(a)).flatMap(a -> {
      seenAnnotations.add(a);
      return concat(deriveConfigs(typeElement, a.getAnnotationType().asElement(), seenAnnotations),
          annotationConfig(typeElement, a));
    });
  }

In the code above you can see HasSet is used, however AnnotationMirror link does declare hashCode method.

Proof:

• You can see that the seenAnnotations set contains many duplicate values (highlighted in yellow)
• and; that .hashCode() call on the Retention policy returns a random hashCode every time.

How I found it

Looking at language server logs.

Affect

I'm not too familiar with derive4j, take below with a grain of salt:

• This issue does not affect code gen.
• I believe the issue leads to miss-configured classPaths

[etherandrius]

Also, this only happens when using eclipse java compiler. Bug does not happen if using javac compiler