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Declared Annotations Issue #10061

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scabug opened this issue Nov 15, 2016 · 3 comments
Closed

Declared Annotations Issue #10061

scabug opened this issue Nov 15, 2016 · 3 comments
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annotations reflection won't fix

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@scabug
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scabug commented Nov 15, 2016

m.getDeclaredAnnotations is an empty array and should not be. This would seem to be a bug as I can't imagine this is the correct behaviour.

import scala.annotation.StaticAnnotation

case class ComplexAnnotation(p1: String, p2: Int, p3: Boolean, p4: (_) => Boolean) extends StaticAnnotation

class TestModel {

  @ComplexAnnotation("test", 4, false, (any: Any) => {
    true
  })
  var var1 = 4

  def reflect() = {
    this.getClass.getDeclaredMethods.foreach(m => {
      println("Method: -")
      println(m)
      m.getDeclaredAnnotations.foreach(a => {
        println("Annotations: -")
        println(a)
      })
    })
  }

}
@scabug
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scabug commented Nov 15, 2016

Imported From: https://issues.scala-lang.org/browse/SI-10061?orig=1
Reporter: Chris Beck (cwbeck)
Affected Versions: 2.12.0
See #7041

@scabug
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scabug commented Nov 15, 2016

Chris Beck (cwbeck) said:
Also worth adding: -

Trying to reflect like this also fails using - import scala.annotation.Annotation, import scala.reflect.runtime.{universe => ru}

    ru.typeOf[TestModel].decls.collect {
      case m: Any => {
        println("method: -")
        println(m)
        m
      }
    }.withFilter {
      _.annotations.nonEmpty
    }.map { m => {
      println("method with annotations: -")
      println(m)
      m

{code}

@scabug
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scabug commented Nov 15, 2016

@lrytz said:
This is a known issue: Scala-defined annotations are never emitted as Java-style annotations in the classfile, and therefore not visible to Java reflection. If you need an annotation to be visible to Java reflection, it needs to be defined in Java.

What you're looking for would be ClassfileAnnotation, not StaticAnnotation, but it's not implemented, you'll get a compile-time warning.

See also #7041

@scabug scabug closed this as completed Nov 15, 2016
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