Handle serializing arrays of primitives [DATAREDIS-509]

[spring-projects-issues]

Maxim Novik opened DATAREDIS-509 and commented

MappingRedisConverter.writeInternal() does a check against properties. If they are "collection like" then there is an additional check for array. However, array is assumed to be an array of objects and is cast to Object[]. That does not work for array of primitives.

if (persistentProperty.isMap()) {
					writeMap(keyspace, propertyStringPath, persistentProperty.getMapValueType(),
							(Map<?, ?>) accessor.getProperty(persistentProperty), sink);
				} else if (persistentProperty.isCollectionLike()) {

					final Object property = accessor.getProperty(persistentProperty);

					if (property == null || Iterable.class.isAssignableFrom(property.getClass())) {

						writeCollection(keyspace, propertyStringPath, (Iterable<?>) property,
								persistentProperty.getTypeInformation().getComponentType(), sink);
					} else if (property.getClass().isArray()) {

						writeCollection(keyspace, propertyStringPath, Arrays.asList((Object[]) property),
								persistentProperty.getTypeInformation().getComponentType(), sink);
					} else {

						throw new RuntimeException("Don't know how to handle " + property.getClass() + " type collection");
					}

If we add the following test to org/springframework/data/redis/core/convert/MappingRedisConverterUnitTests.java:

@Test
    public void writeHandlesArraysOfPrimitivesProperly() {
        WithArrays source = new WithArrays();
        source.arrayOfPrimitives = new int[] { 1, 2, 3 };
        assertThat(write(source).getBucket(), isBucket().containingUtf8String("arrayOfPrimitives.[0]", "1")
                .containingUtf8String("arrayOfPrimitives.[1]", "2")
                .containingUtf8String("arrayOfPrimitives.[2]", "3"));

    }

, it fails with:

java.lang.ClassCastException: [I cannot be cast to [Ljava.lang.Object;

---

Affects: 1.7.1 (Hopper SR1)

Referenced from: pull request #196

Backported to: 1.7.2 (Hopper SR2)

[spring-projects-issues]

Christoph Strobl commented

thanks Maxim Novik for reporting and detailed analysis

[spring-projects-issues]

Maxim Novik commented

In fact, there are more tests failing if we add a primitive array to WithArrays class. But you probably already figured that out.
I tried to come up with a fix to this myself but haven't found an elegant solution yet.
Thanks for looking at this.