Spring boot: 3.2.0, Spring data Couchbase: 5.2.0: java.lang.IllegalArgumentException: Attribute of type java.util.Collections.SingletonList cannot be stored and must be converted.

[ilangranet]

Hi,

I am using Spring boot: 3.2.0 with Spring data Couchbase: 5.2.0

I have an entity defined with a field of type Object (this field can be everything (String or List...)):

public class Person {
    @NotNull
    @Id
    private String id;

    @NotNull
    @Field
    private String name;

    @Field
    private int age;

    @Field
    private Object myObject;
}

while trying to save it using this:
personRepository.save(new Person("1", "Alice", 25, Collections.singletonList("my issue")));

It failed on java.lang.IllegalArgumentException: Attribute of type java.util.Collections.SingletonList cannot be stored and must be converted.

it was working with previous version: Spring boot: 2.7.13, Spring data Couchbase: 4.4.13.
demo.zip

Find attached the project where it failed: to reproduce, run PersonRepositoryTest

Any suggestion?

Thank you

[mikereiche]

This should work and I'll fix it. In the meantime, you might try a JsonArray instead of a List

[ilangranet]

This should work and I'll fix it. In the meantime, you might try a JsonArray instead of a List

I tried and get the same issue:
java.lang.IllegalArgumentException: Attribute of type com.couchbase.client.java.json.JsonArray cannot be stored and must be converted.

[mikereiche]

I haven't investigated this yet, but this is more likely the issue. How is Object supposed to be serialized? Deserialized? What constructor should be used?

@Field
private Object myObject;

[roman-sinyakov]

@mikereiche this is a regression in v5. Could you make it work like it used to be in v4 ?

[mikereiche]

The issue is that conversion.isSimpleType() considers Object to be a simple type, while the

MappingCouchbaseConverter

if (!conversions.isSimpleType(prop.getType())) {
	writePropertyInternal(propertyObj, target, prop, accessor);
} else {
	writeSimpleInternal(prop, accessor, target, prop.getFieldName());
}

While verifyValue (called from target.put() called from writeSimpleInternal()) does not consider it to be a simpletype.
CouchbaseDocument

private void verifyValueType(final Object value) {
	if (value == null) {
		return;
	}
	final Class<?> clazz = value.getClass();
	if (CouchbaseSimpleTypes.DOCUMENT_TYPES.isSimpleType(clazz)) {
		return;
	}
	throw new IllegalArgumentException(
			"Attribute of type " + clazz.getCanonicalName() + " cannot be stored and must be converted.");
}

[mikereiche]

@roman-sinyakov

this is a regression in v5. Could you make it work like it used to be in v4 ?

I can make the serialization (save) work. But it appears that the deserialization (findById etc), did not work in v4 and won't work in v5 without other changes.

The breaking change is in MappingCouchbaseConverter.java. old line 579 vs new line 616 - propertyObj.getClass() (the object) vs prop.getType() (the field on the class)

deca246#diff-ed94230cdca258107738571365038a574bfe8d12f6b1fef0dea3ca4f6b19507fL579

[mikereiche]

@roman-sinyakov @ilangranet - are you ok with saving working, but reading (still) not working?

[ilangranet]

@roman-sinyakov @ilangranet - are you ok with saving working, but reading (still) not working?

with spring data 4.x, save and read were working.
we still need both.

[mikereiche]

I thought I tried reading with 4.x and it didn't work. I'll look again

[ilangranet]

I tried with spring boot 2.7.13, which brings

<dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-couchbase</artifactId>
      <version>4.4.13</version>
      <scope>compile</scope>
</dependency>

PersonRepositoryTest.java.zip

it worked both save and read.

[mikereiche]

Thanks. I'll investigate on Monday.

[mikereiche]

@ilangranet - I can't get the read to work in 4.4.x or in anything else. Since the field type is Object, it doesn't have a componentType (line 766).
So when readCollection() is called at line 776 with componentType==null, it throws an exception because it does not accept a null targetType.

https://github.com/spring-projects/spring-data-couchbase/blob/061f7ab8ed530ecd9337b7d56bfcabba194729f6/src/main/java/org/springframework/data/couchbase/core/convert/MappingCouchbaseConverter.java#L755:L783