[Bug] withPrefabValuesForField() throws for fields declaring interfaces and super-types

[Vankog]

Describe the bug

withPrefabValuesForField() throws precondition exception for interface fields (e.g. java.util.List) if prefab values are interface-implementations or sub-implementations of the defined field type.
e.g. for List it fails for:

• java.util.ArrayList
• java.util.Arrays.ArrayList via java.util.Arrays.asList(T...)
• java.util.Collections.SingletonList, created via java.util.Collections.singletonList(T)

Steps to reproduce

1. Create a POJO with an interface, e.g. java.util.List field.
2. Test POJO with
   .withPrefabValues(List.class, Collections.singletonList(red), Collections.singletonList(blue))
   • works☑️
3. Test POJO with
   .withPrefabValuesForField("myListField", Collections.singletonList(red), Collections.singletonList(blue))
   • fails❌
4. Test POJO with
   .withPrefabValuesForField("myListField", Arrays.asList(red), Arrays.asList(blue))
   • fails❌
5. Test POJO with
   .withPrefabValuesForField("myListField", Collections.unmodifiableList(Arrays.asList(red)), Collections.unmodifiableList(Arrays.asList(blue)))
   • fails❌

Error message and version number

EqualsVerifier v. 3.17.1
JDK 8 Temurin

java.lang.IllegalStateException: Precondition: Prefab values for field subItems should be of type List but are SingletonList.
	at nl.jqno.equalsverifier.internal.util.Validations.validate(Validations.java:270)
	at nl.jqno.equalsverifier.internal.util.Validations.validateFieldTypeMatches(Validations.java:103)
	at nl.jqno.equalsverifier.internal.util.PrefabValuesApi.addPrefabValuesForField(PrefabValuesApi.java:51)
	at nl.jqno.equalsverifier.api.SingleTypeEqualsVerifierApi.withPrefabValuesForField(SingleTypeEqualsVerifierApi.java:146)
	at my.test.DummyClassTest.testEqualsContract(ItemDataTest.java:27)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at java.util.ArrayList.forEach(ArrayList.java:1259)
	at java.util.ArrayList.forEach(ArrayList.java:1259)

Code: EqualsVerifier invocation

        EqualsVerifier.forClass(DummyClass.class)
                      .suppress(Warning.NONFINAL_FIELDS, Warning.STRICT_INHERITANCE)
                      .withPrefabValuesForField("myListField", Collections.singletonList(red), Collections.singletonList(blue))
                      .verify();

Code: class under test

public class DummyClass {
    String id;
    List<String> myListField;
    /* ...equals / hashcode... */
}

Additional context

Using the old
.withPrefabValues(List.class, Collections.singletonList(red), Collections.singletonList(blue))
works.
Thus, the expectation is that it works for withPrefabValuesForField() as well.

EDIT:
Looking at nl.jqno.equalsverifier.internal.util.Validations.validateFieldTypeMatches(Class, String, Class<?>) indicates that this happens with all type hierarchies, as the code uses
boolean sameFields = f.getType().equals(fieldType);
enforcing an exact type match, doesn't it?

EDIT 2: Yes, testing implies that also type hierarchies are affected.
I tested it against a field of type java.lang.Object with any sub-type as prefab values.

[Vankog]

The solution might probably, to use java.lang.Class.isAssignableFrom(Class<?>)

[jqno]

You're completely right. Thanks for the elaborate report, this made it very easy for me to make the fix.

Version 3.17.2 is now syncing with Maven Central!

[Vankog]

Oh, I was too slow ^^
Well, maybe the test helps nonetheless.