Spring Data REST - PUT request does not work prope

Since version 2.5.7 Spring Data REST does not properly perform a PUT request to update resource which has associated resources. Unlike PATCH request that works as expected!

For example, Person has a many-to-one association with Addres. If we perform a PUT request with SDR v.2.5.6 (Spring Boot v.1.4.3) then all works OK. But if we switch to version 2.5.7 (i.e. to Spring Boot v.1.4.4) then we get an error:

Can not construct instance of Address: no String-argument constructor/factory method to deserialize from String value

The same happens with other types of associations, for example with one-to-many (uni- and bidirectional) - see my example application code and tests.

This problem is present in all versions of the Spring Boot since 1.4.4 including the latest stable 1.5.6 version, as well as the newest 2.0.0-SNAPSHOT version!

To work around this situation we can just switch to SDR v.2.5.6 (Spring Boot v.1.4.3).

I've prepared a Postman collection of requests to help you play with the issue: SDR PUT Issue

UPDATE 2017-08-14

I found how to avoid the error Can not construct instance of Address: no String-argument constructor/factory method to deserialize from String value.

Since I'm using Lombok in this project, it is necessary just to tell Lombok to suppress using the @ConstructorProperties annotation in generated constructors. So I set lombok.anyConstructor.suppressConstructorProperties=true in the 'lombok.config' file and the error was gone.

Unfortunately a new problem was found - PUT request does not update associated objects at all!

The example below is demonstrating this. When we are trying to update Person by changing his Address from addresses/1 (initial value) to addresses/2 - then it remains the same: addresses/1! As well as the previous problem this one is present in all versions of the Spring Boot since 1.4.4 (SDR - from v.2.5.7).

I debugged my project and found out that the reason of the issue is hidden in the method DomainObjectReader#mergeForPut (see its source) - it never replaces associated resources with new ones.

Before I post this issue on Spring JIRA, please report here if you have this issue in your projects and what do you think about it.

You can get my test here and check it in your projects - the test is 'standalone' and doesn't depend from other classes/modules (exclude only H2, I hope).

@Entity
public class Person {

    private String name;

    @ManyToOne
    private Address address;

    // other stuff
}

@Entity    
public class Address {

    private String street;

    // other stuff
}

Trying to update Person:

PUT http://localhost:8080/api/persons/1

{
    "name": "person1u",
    "address": "http://localhost:8080/api/addresses/2"
}

Getting the correct response:

{
    "name": "person1u",
    "_links": {
        "self": {
            "href": "http://localhost:8080/api/persons/1"
        },
        "person": {
            "href": "http://localhost:8080/api/persons/1"
        },
        "address": {
            "href": "http://localhost:8080/api/persons/1/address"
        }
    }
}

Then checking for a 'new' Address of Person - address was not updated:

GET http://localhost:8080/api/persons/1/address

{
    "street": "address1",
    "_links": {
        "self": {
            "href": "http://localhost:8080/api/addresses/1"
        },
        "address": {
            "href": "http://localhost:8080/api/addresses/1"
        }
    }
}

UPDATE 2017-08-24

Thanks to Scott C. answer, it turned out that SDR has a bug, which is described in two tickets: DATAREST-1001 and DATAREST-1012.

回答1:

Looks like the issue has already been reported as a bug: - please verify. As best as I can tell, this is the issue you are reporting above.

Note, I am revising my previous answer to be this bug report.

回答2:

I agree with you that this is a bug in Spring Data REST and it should be reported.

I have the same issue in my project, where updating an entity via PATCH request works fine, but PUT request updates only fields of the given entity, but not its associated resources.

Why do I consider this a bug?

As people have correctly pointed out, PUT should be used for replacing a resource as a whole with a modified version, which suggests that it should be working, if you provide all fields for the resource (as in a POST request). However, in current Spring Data REST version, only the simple fields of an entity are updated and the associated resources are left intact which makes PUT request only "partially working" and that is definately not an expected behavior (even if it fulfills the RFC).
Moreover, Spring Data REST even allows you to do a partial PUT request, i.e. updating just your name field via PUT works. It does not work for the address though.
It means that Spring Data REST does not work exactly how the RFC specifies it (which may be for another debate), however it also does not provide a consistent usage - when updating one field works and updating other does not without any sign of an error.

For the record, I am using Spring Data REST 2.6.3.