Sealed interface may be cause of StackOverflowError because of recursion

[JarKz]

Describe the bug
When type A have a field of interface type, which is sealed. And this type permits only type that have a field of type A. If i don't prefab type A with non-null field of interface type, verifier will seek sealed types and return to base Type, and again seek sealed types...

For better clarification, I put the example below. In the code I have three types: type A, sealed interface I and it's permitted type E. Type A have a field of sealed interface I and the permitted type E have a field of type A. It's the simple way to call recursion.

To Reproduce
Put the code below into any test container and run.

Code that triggers the behavior

import java.util.Objects;
import nl.jqno.equalsverifier.EqualsVerifier;
import org.junit.jupiter.api.Test;

class AppTest {

  @Test
  public void testEV() {
    EqualsVerifier.forClass(A.class).verify();
  }

  class A {
    public I sealedClassField;

    @Override
    public int hashCode() {
      return Objects.hash(sealedClassField);
    }

    @Override
    public boolean equals(Object obj) {
      if (this == obj) return true;
      if (!(obj instanceof A)) return false;
      A other = (A) obj;
      return Objects.equals(sealedClassField, other.sealedClassField);
    }
  }

  public sealed interface I permits E {}

  public final class E implements I {

    public A referenceToA;

    @Override
    public int hashCode() {
      return Objects.hash(referenceToA);
    }

    @Override
    public boolean equals(Object obj) {
      if (this == obj) return true;
      if (!(obj instanceof E)) return false;
      E other = (E) obj;
      return Objects.equals(referenceToA, other.referenceToA);
    }
  }
}

Error message

java.lang.AssertionError: EqualsVerifier found a problem in class ev.AppTest$A.
-> <no message>

For more information, go to: https://www.jqno.nl/equalsverifier/errormessages
(EqualsVerifier 3.15.6, JDK 17.0.9 on Mac OS X)
	at nl.jqno.equalsverifier.api.SingleTypeEqualsVerifierApi.verify(SingleTypeEqualsVerifierApi.java:351)
	at ev.AppTest.testEV(AppTest.java:14)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
Caused by: java.lang.StackOverflowError
	at java.base/java.util.stream.StreamSupport.stream(StreamSupport.java:70)
	at java.base/java.util.Arrays.stream(Arrays.java:5447)
	at java.base/java.util.Arrays.stream(Arrays.java:5428)
	at java.base/java.lang.Class.getPermittedSubclasses(Class.java:4515)
	at java.base/java.lang.Class.isSealed(Class.java:4566)
	at nl.jqno.equalsverifier.internal.reflection.SealedTypesHelper.isSealed(SealedTypesHelper.java:12)
	at nl.jqno.equalsverifier.internal.reflection.Instantiator.of(Instantiator.java:50)
	at nl.jqno.equalsverifier.internal.reflection.ClassAccessor.buildObjectAccessor(ClassAccessor.java:278)
	at nl.jqno.equalsverifier.internal.reflection.ClassAccessor.getRedAccessor(ClassAccessor.java:196)
	at nl.jqno.equalsverifier.internal.reflection.ClassAccessor.getRedObject(ClassAccessor.java:185)
	at nl.jqno.equalsverifier.internal.prefabvalues.factories.FallbackFactory.giveInstances(FallbackFactory.java:95)
	at nl.jqno.equalsverifier.internal.prefabvalues.factories.FallbackFactory.createValues(FallbackFactory.java:40)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.createTuple(PrefabValues.java:157)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.realizeCacheFor(PrefabValues.java:140)
	at nl.jqno.equalsverifier.internal.prefabvalues.factories.FallbackFactory.traverseFields(FallbackFactory.java:88)
	at nl.jqno.equalsverifier.internal.prefabvalues.factories.FallbackFactory.createValues(FallbackFactory.java:39)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.createTuple(PrefabValues.java:157)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.realizeCacheFor(PrefabValues.java:140)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.giveTuple(PrefabValues.java:81)
	at nl.jqno.equalsverifier.internal.prefabvalues.PrefabValues.giveOther(PrefabValues.java:104)
	at nl.jqno.equalsverifier.internal.reflection.FieldModifier.lambda$changeField$2(FieldModifier.java:97)
	at nl.jqno.equalsverifier.internal.reflection.FieldModifier.wrappedChange(FieldModifier.java:118)
	at nl.jqno.equalsverifier.internal.reflection.FieldModifier.lambda$change$3(FieldModifier.java:113)
	at nl.jqno.equalsverifier.internal.util.Rethrow.lambda$rethrow$1(Rethrow.java:51)
	at nl.jqno.equalsverifier.internal.util.Rethrow.rethrow(Rethrow.java:34)
	at nl.jqno.equalsverifier.internal.util.Rethrow.rethrow(Rethrow.java:49)
	at nl.jqno.equalsverifier.internal.util.Rethrow.rethrow(Rethrow.java:59)
	...infinity repeated rows are omitted.

Expected behavior
Throw an error that describes the recursion of this case.

Or disable this checker for sealed intrefaces by adding suppression or calling a method (i.e. verifySealedTypes(false)) before the method verify().

Version
I use latest version at this moment: 3.15.6.

Additional context
I understand, if you will say me that I must not use the field of type A in permitted type E. But it's not my desire. I have a lot of autogenerated types for API and I don't want to allow another user of library to implement an interface I. And I already sure that these premitted types are valid by EqualsVerifier package, so I want only turn off this uncomfortable function.

[jqno]

Thanks for the code example, it was very easy to reproduce the issue that way.
Finding a solution is less easy, I'll let you know when I have something. In the mean time, I recommend that you use the workaround you've already found, of adding prefab values for A.

[jqno]

Version 3.15.7 is now syncing with Maven Central. It will give you a clean recursion error, instead of a StackOverflowError.

There's still some edge cases I should probably work out, but I think this should solve your issue.

[JarKz]

Thank you very much! It solved my problem!

I'm very glad to continue my coding without friction.

[jqno]

Glad to hear it!