[GROOVY-9452] Multiple Repeatable Annotations Container generated if an explicit container is present and an implicit one required

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.8, 3.0.0
• Fix Version/s: 4.0.0-alpha-1, 3.0.3
• Assignee: Paul King
• Reporter: Björn Kautler
• Created: 09/Mar/20 15:02
• Updated: 11/Nov/20 02:00
• Resolved: 04/Apr/20 05:49

Description

Given:

• an annotation A with String value which is repeatable with container annotation As

If you in Java write

@A("a")
@As({
  @A("c")
  @A("d")
}) 

this is transported 1:1 to the byte code and if you use getAnnotationsByType(A.class) you properly get all three annotations.

If you in Java write

@A("a")
@A("b")
@As({
  @A("c")
  @A("d")
}) 

you get a compile error saying that this does not work.

If you in Groovy write

@A("a")
@As([
  @A("c")
  @A("d")
]) 

this is transported 1:1 to the byte code and if you use getAnnotationsByType(A.class) you properly get all three annotations.
All ok.

But now comes the issue.
If you in Groovy write

@A("a")
@A("b")
@As([
  @A("c")
  @A("d")
]) 

you end up with two @As annotations in the final class file.
If you then try to read annotations for example at runtime, you get

java.lang.annotation.AnnotationFormatError: Duplicate annotation for class: interface As: @As(value=[@A(value="a"), @A(value="b")])
	at sun.reflect.annotation.AnnotationParser.parseAnnotations2(AnnotationParser.java:125)
	at sun.reflect.annotation.AnnotationParser.parseAnnotations(AnnotationParser.java:72)
	at java.lang.reflect.Executable.declaredAnnotations(Executable.java:599)
	at java.lang.reflect.Executable.declaredAnnotations(Executable.java:597)
	at java.lang.reflect.Executable.getAnnotation(Executable.java:570)
	at java.lang.reflect.Method.getAnnotation(Method.java:622)
        ...

So the Groovy compiler should probably also refuse to go on if there are mutliple single instances of a repeatable annotation if the respective container annotation is already present.

Issue Links

• links to: GitHub Pull Request #1215