Properties naming strategy do not work with Record

Hello,

When I try to use a @JsonNaming annotation on a record, I cannot unmarshall json to an object because a mapping exception occurs.

I use jackson 2.12.0 with JDK 15.

A Test example can be something like:

    @Test
    void tryJsonNamingOnRecord() throws Exception{
        ObjectMapper mapper=new ObjectMapper();

        @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
                record Test(String myId, String myValue){}

        var src=new Test("id", "value");
        String json=mapper.writeValueAsString(src);
        assertThat(json).contains("\"my_id\":\"id\"", "\"my_value\":\"value\"");
        var after=mapper.readValue(json, Test.class);
        assertThat(after).isEqualTo(src);
    }

The json String is generated correctly, but when unmarshalling, I got an exception

com.fasterxml.jackson.databind.JsonMappingException: Can not set final java.lang.String field test.Tests$1Test.myValue to java.lang.String
	at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:274)
	at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:623)
	at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:611)
	at com.fasterxml.jackson.databind.deser.SettableBeanProperty._throwAsIOE(SettableBeanProperty.java:634)
	at com.fasterxml.jackson.databind.deser.impl.FieldProperty.set(FieldProperty.java:193)
	at com.fasterxml.jackson.databind.deser.impl.PropertyValue$Regular.assign(PropertyValue.java:62)
	at com.fasterxml.jackson.databind.deser.impl.PropertyBasedCreator.build(PropertyBasedCreator.java:211)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:520)
	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1390)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:362)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:195)
	at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:322)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4591)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3546)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3514)
	at test.Tests.tryJsonNamingOnRecord(Tests.java:100)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	...
	at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:688)
	at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
...
Caused by: java.lang.IllegalAccessException: Can not set final java.lang.String field test.Tests$1Test.myValue to java.lang.String
	at java.base/jdk.internal.reflect.UnsafeFieldAccessorImpl.throwFinalFieldIllegalAccessException(UnsafeFieldAccessorImpl.java:76)
	at java.base/jdk.internal.reflect.UnsafeFieldAccessorImpl.throwFinalFieldIllegalAccessException(UnsafeFieldAccessorImpl.java:80)
	at java.base/jdk.internal.reflect.UnsafeQualifiedObjectFieldAccessorImpl.set(UnsafeQualifiedObjectFieldAccessorImpl.java:79)
	at java.base/java.lang.reflect.Field.set(Field.java:793)
	at com.fasterxml.jackson.databind.deser.impl.FieldProperty.set(FieldProperty.java:190)
	... 76 more

[cowtowncoder]

@cgpassante Unfortunately there is no concrete idea: problem is that it would be fixable as part of big rewrite of property introspection. But I have not found enough contiguous time to spend on tackling this (I only work on Jackson during my spare time): it could be that I might be able to do that within next month if something opened up. And yet with all the other things going on, it may be that it won’t happen this year.

What I do not want to try is a one-off hack to work around just this problem since that tends to complicate eventual rewrite.

I agree that this problem area – proper support of Java Records – is VERY important, and I try my best to find time to resolve it properly.

[jedvardsson]

Great. I will only use my fix will until 2.13. Here is a version that does not modify in place:

package com.examaple.jackson;

import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.DeserializationConfig;
import com.fasterxml.jackson.databind.deser.SettableBeanProperty;
import com.fasterxml.jackson.databind.deser.ValueInstantiator;
import com.fasterxml.jackson.databind.deser.ValueInstantiators;
import com.fasterxml.jackson.databind.deser.std.StdValueInstantiator;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.module.SimpleModule;

import java.util.Arrays;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;

public class RecordNamingStrategyPatchModule extends SimpleModule {

    @Override
    public void setupModule(SetupContext context) {
        context.addValueInstantiators(new ValueInstantiatorsModifier());
        super.setupModule(context);
    }

    /**
     * Remove when the following issue is resolved: 
     * <a href="https://github.com/FasterXML/jackson-databind/issues/2992">Properties naming strategy do not work with Record #2992</a>
     */
    private static class ValueInstantiatorsModifier extends ValueInstantiators.Base {
        @Override
        public ValueInstantiator findValueInstantiator(
                DeserializationConfig config, BeanDescription beanDesc, ValueInstantiator defaultInstantiator
        ) {
            if (!beanDesc.getBeanClass().isRecord() || !(defaultInstantiator instanceof StdValueInstantiator) || !defaultInstantiator.canCreateFromObjectWith()) {
                return defaultInstantiator;
            }
            Map<String, BeanPropertyDefinition> map = beanDesc.findProperties().stream().collect(Collectors.toMap(p -> p.getInternalName(), Function.identity()));
            SettableBeanProperty[] renamedConstructorArgs = Arrays.stream(defaultInstantiator.getFromObjectArguments(config))
                    .map(p -> {
                        BeanPropertyDefinition prop = map.get(p.getName());
                        return prop != null ? p.withName(prop.getFullName()) : p;
                    })
                    .toArray(SettableBeanProperty[]::new);

            return new PatchedValueInstantiator((StdValueInstantiator) defaultInstantiator, renamedConstructorArgs);
        }
    }

    private static class PatchedValueInstantiator extends StdValueInstantiator {

        protected PatchedValueInstantiator(StdValueInstantiator src, SettableBeanProperty[] constructorArguments) {
            super(src);
            _constructorArguments = constructorArguments;
        }
    }
}