Custom java time module ignored after upgrade to 2.16

[Sjoerd97]

Specs:
Java 17
Gradle 8
Jackson 2.16

Recently we upgrade from 2.15.2 to 2.16 and our deserialization broke.
Somehow our "CustomDateTimeDeserializer" is no longer used whenever we register a JsonMapper.
Whenever we annotate the field we want to deserialize with @JsonDeserialize it does work, but this is not a feasible solution in our case.

`class CustomDateTimeDeserializerTest {

private static final JsonMapper JSON_MAPPER = JsonMapper.builder()
	.addModule(new JavaTimeModule().addDeserializer(LocalDateTime.class, new CustomDateTimeDeserializer()))
	.build();

@Test
void deserializeSummerTime() throws JsonProcessingException {
	LocalDateTimeObject ldtAmsterdam = JSON_MAPPER.readValue("{ \"ldt\": \"2023-04-25T12:39:10Z\" }", LocalDateTimeObject.class);
	assertEquals(LocalDateTime.of(2023, 4, 25, 14, 39, 10), ldtAmsterdam.ldt());
}`

[JooHyukKim]

It just stopped working? 🤔

[JooHyukKim]

We need reproducible and hopefully minimal test case with

• ObjectMapper configurations
• How classes are declared, like custom deserializers, beans, etc..

[JooHyukKim]

@Sjoerd97 Oh wait, can you check below reproduction? As far as I understood below snipet matches your description, but the test both works in 2.15 and 2.16

public class S00Test
    extends ModuleTestBase {

    static class CustomDateTimeDeserializer extends LocalDateTimeDeserializer {
        private static final long serialVersionUID = 1L;

        public CustomDateTimeDeserializer() {
            super(DateTimeFormatter.ISO_DATE_TIME);
        }

        @Override
        protected LocalDateTimeDeserializer withDateFormat(DateTimeFormatter dtf) {
            return new LocalDateTimeDeserializer();
        }

        @Override
        public LocalDateTime deserialize(JsonParser parser, DeserializationContext context) throws IOException {
            throw new RuntimeException("Override works!");
        }
    }

    private static final JsonMapper JSON_MAPPER = JsonMapper.builder()
        .addModule(new JavaTimeModule().addDeserializer(LocalDateTime.class, new CustomDateTimeDeserializer()))
        .build();

    static class LocalDateTimeObject {
        public LocalDateTime ldt;

        public LocalDateTime ldt() {
            return ldt;
        }
    }

    @Test
    public void testDeserializeSummerTime() throws JsonProcessingException {
        try {
            LocalDateTimeObject ldtAmsterdam = JSON_MAPPER.readValue("{ \"ldt\": \"2023-04-25T12:39:10Z\" }", LocalDateTimeObject.class);
        } catch (JsonMappingException e) {
            assertEquals("Override works!", e.getCause().getMessage());
        }
    }
}

[Sjoerd97]

Sure will do!

We dont use an ObjectMapper but rather a JsonMapper.
To reproduce you can take the code snippet and put a random break point in a random overide of the deserialize method and you will see that the break point is never reached.
We dont use spring in this project.
Hopefully this is enough otherwise let me know

[JooHyukKim]

We dont use an ObjectMapper but rather a JsonMapper.

I used JsonMapper in above reproduction.

To reproduce you can.....// omitted rest

Yup, I overrided deserialize() and made it throw new RuntimeException("Override works!")

[Sjoerd97]

Ill have a look at your example, will confirm tomorrow

[Sjoerd97]

The issue is fixed in the 2.16.1 release, thanks!