[GROOVY-8236] Report more meaningful error for versions of Groovy not supporting @Repeatable

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.4.13
• Environment: groovy 2.4.11
• Assignee: Paul King
• Reporter: Dmitry Lukyanov
• Created: 23/Jun/17 12:08
• Updated: 06/Mar/18 23:25
• Resolved: 14/Jul/17 03:34

Description

I cloned the issue. As well as providing support for @Repeatable, we should give a more meaningful error message for any streams of Groovy where we don't support it. I'd guess supported (2.5.0), unsupported (2.4.x); but in any case, this issue is to handle the unsupported case.

Instead of:

java.lang.annotation.AnnotationFormatError ...

We could have something like:

Annotation @MyAnnotation has RUNTIME retention and 2 occurrences.
Automatic repeated annotations are not allowed in this version of Groovy.
Consider explicitly adding the @MyAnnotationArray collector annotation.

---- original description -----

raised on stackoverflow: https://stackoverflow.com/questions/44532632/is-the-repeatable-annotation-not-supported-by-groovy/44628119#44628119

Problem: the following code in groovy 2.4.11 / java8

   @MyAnnotation(value = "val1")
   @MyAnnotation(value = "val2")
   void annotatedMethod() { println("annotated method called") }

should be compiled to this:

   @MyAnnotationArray({@MyAnnotation("val1"), @MyAnnotation("val2")})
   void annotatedMethod() { println("annotated method called") }

but actually compiled to this:

   @MyAnnotation(value = "val1")
   @MyAnnotation(value = "val2")
   void annotatedMethod() { println("annotated method called") }

The full groovy script to reproduce problem is below.
It throws exception:
java.lang.annotation.AnnotationFormatError: Duplicate annotation for class: interface MyAnnotation: @MyAnnotation(value=val2)

at line `List annos = m.getAnnotations()`

import java.lang.annotation.*

class MyClass 
{
    @MyAnnotation(value = "val1")
    @MyAnnotation(value = "val2")
    //change annotation to next line and the code will work
    //@MyAnnotationArray( [@MyAnnotation("val1"), @MyAnnotation("val2")] )
    public void annotatedMethod()
    {
      System.out.println("annotated method called");
    }
   public static void main(String... args)
   {
      MyClass ob = new MyClass()
      ob.annotatedMethod()
      java.lang.reflect.Method m = ob.getClass().getMethod("annotatedMethod")
      List annos = m.getAnnotations()
      println("annos = $annos")
   }
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Repeatable(MyAnnotationArray) 
public @interface MyAnnotation
{
    String value() default "val0";
}

@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotationArray 
{
   MyAnnotation[] value()
}

Issue Links

• is a clone of: GROOVY-8234 Add @Repeatable java8 annotation support
• links to: GitHub Pull Request #565