Exception when deserialization uses a record with a constructor property with `access=READ_ONLY`

[Mochis]

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Describe the bug

When deserialization uses a record with a constructor property with access=READ_ONLY, the following exception is thrown:

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Invalid type definition for type `com.company.common.vo.RuleVO`: Argument #1 of constructor [constructor for `com.company.common.vo.RuleVO` (4 args), annotations: [null] has no property name annotation; must have name when multiple-parameter constructor annotated as Creator
 at [Source: (BufferedReader); line: 1, column: 1]
	at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:62)
	at com.fasterxml.jackson.databind.DeserializationContext.reportBadTypeDefinition(DeserializationContext.java:1893)
	at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory._addImplicitConstructorCreators(BasicDeserializerFactory.java:602)
	at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory._constructDefaultValueInstantiator(BasicDeserializerFactory.java:301)
	at com.fasterxml.jackson.databind.deser.BasicDeserializerFactory.findValueInstantiator(BasicDeserializerFactory.java:222)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.buildBeanDeserializer(BeanDeserializerFactory.java:262)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerFactory.createBeanDeserializer(BeanDeserializerFactory.java:151)
	at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer2(DeserializerCache.java:415)
	at com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:350)
	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:264)
	at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:244)
	at com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:142)
	at com.fasterxml.jackson.databind.DeserializationContext.findContextualValueDeserializer(DeserializationContext.java:621)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.createContextual(CollectionDeserializer.java:188)
	at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.createContextual(CollectionDeserializer.java:28)
	at com.fasterxml.jackson.databind.DeserializationContext.handleSecondaryContextualization(DeserializationContext.java:867)
	at com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:659)
	at com.fasterxml.jackson.databind.ObjectMapper._findRootDeserializer(ObjectMapper.java:4956)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4826)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3801)

A sample record is provided bellow.

Version Information

2.15.2

Reproduction

Sample record with the issue:

public record RuleVO(
  @JsonIgnore
  Integer id,

  @JsonProperty(access = JsonProperty.Access.READ_ONLY)
  Integer order,

  @JsonProperty(access = JsonProperty.Access.READ_ONLY)
  String name,

  String description,
) {}

If I remove the JsonProperty.Access.READ_ONLY from order field, a new exception is thrown indicating the argument with the issue is ...: Argument #2 of constructor [constructor for..., that is, the other field with READ_ONLY.

The object mapper is:

  public static ObjectMapper customObjectMapper() {
    return JsonMapper.builder()
      .addModule(new JavaTimeModule())
      .disable(MapperFeature.DEFAULT_VIEW_INCLUSION)
      .disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
      .build();
  }

I also tried with a plain object mapper JsonMapper.builder().build() without customizations and the error is still there.

Expected behavior

In 2.14.3, it works perfectly.

Additional context

I have tested the application with 2.15.3-SNAPSHOT and 2.16.0-SNAPSHOT and the error is thrown too.

[yawkat]

you probably need to define the name explicitly if you use @JsonProperty.

[soc]

One of the benefits of record is that you have first-class support for getting the names (Class#getRecordComponents), so losing that feels kinda wrong.

[yawkat]

oh duh, the issue is much more simple. since you define the property as READ_ONLY, it can't be deserialized. the error could be better but there is no functional change needed here imo.

[Mochis]

I tried to put a name explicitly, but didn't work.

since you define the property as READ_ONLY, it can't be deserialized

Before 2.15.x the result of deserialize or ignoring on deserialization a field with access=READ_ONLY was a null value, I don't understand why it should change to an exception.

For me this is a regression because with the previous version 2.14.3 it works, the change to 2.15.x is not a major change according semver and this is not compatible with previous versions if it was intended.

[yawkat]

I would not call it a regression, I would call it finally having the right behavior :)

AIUI, the record implementation changed a lot 2.14->2.15. It now uses most of the existing bean infrastructure instead of its own special handling. That means aspects that were previously not implemented for records, now are.

But once again this is @cowtowncoder's call.

[Mochis]

Thank you @yawkat for the explanation.

I'm curious about your reasoning, how would you use the READ_ONLY property instead, only to throw an exception when the JSON input contains a field marked with it?

My use case is to use the same value object class to serialize and deserialize, but I want to ignore some JSON fields when deserializing, that's the reason why READ_ONLY is useful in my understanding.

[cowtowncoder]

Hmmh. Semantics of READ_ONLY predate introduction of Records, and with POJOs things are bit simpler.
But I think that it is reasonable to expect Record to work same as a POJO with constrictor regarding this case. I am not 100% sure what that behavior is.

But I agree that at very least exception thrown is not good.
So I think there is a valid issue here. If anyone has time to see how POJO would behave, that'd be useful information.

[yawkat]

normal beans behave the same way. this constructor:

        @JsonCreator
        public Bean(@JsonProperty("foo") String foo, @JsonProperty(value = "bar", access = JsonProperty.Access.READ_ONLY) String bar) {

fails with

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Invalid type definition for type `com.fasterxml.jackson.databind.records.RecordImplicitName4119Test$Bean`: Argument #1 of constructor [constructor for `com.fasterxml.jackson.databind.records.RecordImplicitName4119Test$Bean` (2 args), annotations: {interface com.fasterxml.jackson.annotation.JsonCreator=@com.fasterxml.jackson.annotation.JsonCreator(mode=DEFAULT)} has no property name (and is not Injectable): can not use as property-based Creator
 at [Source: (String)"{"foo":"fizz","bar":"buzz"}"; line: 1, column: 1]

[cowtowncoder]

Ok. So at least we know handling is the same. Questions would then be:

1. Should READ_ONLY setting work via constructor -- and if so, would a null be passed?
2. If failure should occur (this use case not allowed), how to improve exception message.