members of Interface TypeInformation are null when AOP and Data Rest are enabled and a bean is marked @Lazy

[james-bryant]

I have encountered a very strange issue and I'm not sure what to make of it.
It seems that: if AOP is enabled, Spring Data Rest is enabled, and a bean is marked @Lazy, then the constants in TypeInformation return null instead of thier expected values. I was able to narrow this down to a minimal example project.

lazy-proxy-issue.zip

That example project encompasses pretty much everything I know about this problem in the most minimal form I could find; but I'm more than happy to answer any questions if I can.

[wilkinsona]

Thanks for the report.

I've managed to reduce things down quite a bit more and can reproduce the failure with the following:

package com.example.lazyproxyissue;

import static org.assertj.core.api.Assertions.assertThat;

import org.junit.jupiter.api.Test;
import org.springframework.data.util.ClassTypeInformation;
import org.springframework.data.util.TypeInformation;

public class SimplifiedTests {

	@Test
	void typeInformationMapIsNotNull() {
		Object whatever = ClassTypeInformation.MAP;
		assertThat(TypeInformation.MAP).isNotNull();
	}

}

The test fails as TypeInformation.MAP is null. The test passes when Object whatever = ClassTypeInformation.MAP; is commented out. I think this is a bug in Spring Data Commons. As far as I can tell, to work as intended certain classes and interfaces have to be initialized in a particular order. If that order isn't used, constants on TypeInformation become null.

Please open a Spring Data Commons issue so that the Spring Data team can investigate.