Document changes in rendering of PageImpl instances in Spring Boot 3.3 migration guide

[samuelstein]

During the migration to Spring Boot 3.3 I recently stumbled over the changes when rendering org.springframework.data.domain.PageImpl instances to JSON. In my case an additional field wasn't any longer present in the response.

The prefered way is now to wrap the response in PagedModel class or use the @EnableSpringDataWebSupport annotation. To find this out it took me hours unfortunately.
I couldn't find a hint in Spring Boot 3.2 and Spring Boot 3.3 migration guide.
Could you please add a note there?

[wilkinsona]

Thanks for the suggestion. We'd prefer to link out to something provided by the Spring Data project rather than documenting it ourselves. I'll ask the Data team if they have such a thing.

[wilkinsona]

I assume, given that you've mentioned both Boot 3.2 and 3.3, that you're upgrading from 3.1. The Data team are a bit puzzled as "all we added for 3.3 is a warning and a mechanism to flip all renderings to a new, preferred model". Can you please share a minimal sample that works with Spring Boot 3.1.x and requires changes to continue to work in the same way with Spring Boot 3.3.x?

[samuelstein]

Sure.
I did a upgrade from Spring Boot 3.2.5.
We had before the upgrade a ResponsePage which extendend PageImpl with an additional field for a header row:

public class ResponsePageWithHeaderRow<T, U extends Serializable> extends PageImpl<T> {

@Getter
private U headerRow;

...
}

After the upgrade to Spring Boot 3.3.2 the additional field headerRow was missing wheater I added and configured the @EnableSpringDataWebSupport annotation or not.
It only worked after extending and returnig PagedModel.

[wilkinsona]

Thank you. Could you please turn that snippet into a minimal example that we can build and run to observe the behaviour you have described?

[wilkinsona]

It looks like the use of extension may be what's causing the problem. The Data team are going to investigate and add something to https://github.com/spring-projects/spring-data-commons/wiki/Spring-Data-2024.0-Release-Notes if necessary.

On the Boot side, I've updated the Dependency Upgrades section of our 3.3 release notes to link to Spring Data's release notes.

[odrotbohm]

It looks like the problem is caused by our registration of a Jackson Converter to produce a warning log but not actually converting the source value. However, in BeanSerializerFactory.createSerializer(…)Jackson inspects the Converter's generics and builds a serializer for that type. As we, of course, declare that to Page, this process then only considers properties exposed on it and ultimately causes the custom properties not considered.

I think Jackson could fix this by using the more concrete type of the two, i.e. testing for assignability and sticking to the original type if that's assignable to the detected one. I'll go ahead and open a ticket with Jackson to get this fixed. Meanwhile, I'll investigate whether we can use different means to produce the log message, so that we might not have to wait for Jackson to fix this.

[odrotbohm]

We found a less invasive way of issuing the warning, which will make it into the Spring Data releases tomorrow, picked up by the Boot releases next week. I'll make sure we leave a note about the changes in general in the official changelog.

[wilkinsona]

Thanks, @odrotbohm.

[samuelstein]

Thank you very much for the quick response, explanation and fix!