AnnotationMetadataReadingVisitor.getMetaAnnotationTypes(String) may return null but it is not marked @Nullable [SPR-17046]

[spring-projects-issues]

Andy Wilkinson opened SPR-17046 and commented

I've noticed that AnnotationMetadataReadingVisitor.getMetaAnnotationTypes(String) will return null rather than the documented empty Set in two scenarios:

1. getMetaAnnotationTypes is called with the name of an annotation that is not present
2. getMetaAnnotationTypes is called with the name of an annotation that is present but that is not on the classpath

I've attached a small sample that hopefully illustrates both. It tests with Framework 5.1 snapshots but I believe that 5.0 is also affected and perhaps 4.3.x too.

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Affects: 5.0.7

Attachments:

• null-meta-annotation-types.zip (49.32 kB)

Issue Links:

• AnnotationMetadata.getAnnotationAttributes inconsistency for empty array in ASM implementation [SPR-17347] #21881 AnnotationMetadata.getAnnotationAttributes inconsistency for empty array in ASM implementation

[spring-projects-issues]

Juergen Hoeller commented

Indeed, getMetaAnnotationTypes is not meant to ever return null... StandardAnnotationMetadata adheres to that, so AnnotationMetadataReadingVisitor simply returns an empty Set in those cases as well now.

I'll backport this to 5.0.8 but intend to leave 4.3.x as-is unless there is an immediate issue with it.