Kryo does not correctly support parameterized type hierarchy

[mathieucarbou]

Test case:

@RunWith(JUnit4.class)
public class SerializationTest {

  @Test
  public void testParameterizedTypesSupport() throws Exception {
    LongHolder o1 = new LongHolder(1L);
    LongListHolder o2 = new LongListHolder(asList(1L));

    Kryo kryo = new Kryo();
    Output buffer = new Output(512, 4048);
    kryo.writeClassAndObject(buffer, o1);
    kryo.writeClassAndObject(buffer, o2);
  }

  interface Holder<V> {
    V getValue();
  }

  static abstract class AbstractValueHolder<V> implements Holder<V> {
    private final V value;

    AbstractValueHolder(V value) {
      this.value = value;
    }

    @Override
    public V getValue() {
      return value;
    }
  }

  static abstract class AbstractValueListHolder<V> extends AbstractValueHolder<List<V>> {
    AbstractValueListHolder(List<V> value) {
      super(value);
    }
  }

  static class LongHolder extends AbstractValueHolder<Long> {
    LongHolder(Long value) {
      super(value);
    }
  }

  static class LongListHolder extends AbstractValueListHolder<Long> {
    LongListHolder(List<Long> value) {
      super(value);
    }
  }
}

Error:

com.esotericsoftware.kryo.KryoException: java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.lang.Long
Serialization trace:
value (org.terracotta.management.SerializationTest$LongListHolder)

    at com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:101)
    at com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:518)
    at com.esotericsoftware.kryo.Kryo.writeClassAndObject(Kryo.java:628)
    at org.terracotta.management.SerializationTest.testParameterizedTypesSupport(SerializationTest.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.lang.Long
    at com.esotericsoftware.kryo.serializers.DefaultSerializers$LongSerializer.write(DefaultSerializers.java:141)
    at com.esotericsoftware.kryo.Kryo.writeObjectOrNull(Kryo.java:606)
    at com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:87)
    ... 29 more

Cause:

Kryo reuses the same CachedField instance it previously encountered, but the type changed.

[mathieucarbou]

FYI @rkavanap

[rgilles]

Hi,
I get exactly the same result if I change the test method as follow:

    @Test
    public void testParameterizedTypesSupport() throws Exception {
//        LongHolder o1 = new LongHolder(1L);
        LongListHolder o2 = new LongListHolder(asList(1L));

        Kryo kryo = new Kryo();
        Output buffer = new Output(512, 4048);
//        kryo.writeClassAndObject(buffer, o1);
        kryo.writeClassAndObject(buffer, o2);
    }

======
com.esotericsoftware.kryo.KryoException: java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.lang.Long

As you can see the error comes from the generic usage. If I remove the first serialization it fails.

Best regards.

[jlmorton]

I believe this is a regression from the following commit: 4764dee

Reverting this commit causes this test to pass.

The superclass for LongListHolder is AbstractValueListHolder, which is parameterized with Long. This is the type that is found in FieldSerializerGenericsUtil#buildGenericsScope at line 79.

I'm not sure what the fix for this is, but at this point generic scope is set to Long, and Kryo ultimately gets a LongSerializer when it needs to serialize a list.

[magro]

Resolved by #433