Fragment repository implementation should be imported even it's not in basePackages of @EnableJpaRepositories

[quaff]

Given:

package com.example.demo;

public interface CustomRepository<T> {
	
	void customSave(T entity);

}

package com.example.demo;

public class CustomRepositoryImpl<T> implements CustomRepository<T> {

	@Override
	public void customSave(T entity) {
		throw new UnsupportedOperationException("Not Implemented");
	}

}

package test;

import org.springframework.data.jpa.repository.JpaRepository;

import com.example.demo.CustomRepository;

public interface TestEntityRepository extends JpaRepository<TestEntity, Long>, CustomRepository<TestEntity> {

}

Then:

com.example.demo.CustomRepositoryImpl should be registered as repository fragment implementation implicitly since com.example.demo.CustomRepository is declared as repository fragment.

Actual:

Here is a failed test

package test;

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

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.test.context.ContextConfiguration;

@DataJpaTest
//@EnableJpaRepositories(basePackageClasses = { TestEntityRepository.class, CustomRepository.class }) // will works
@EnableJpaRepositories(basePackageClasses = { TestEntityRepository.class })
@EntityScan(basePackageClasses = TestEntity.class)
@ContextConfiguration(classes = TestEntityRepositoryTests.class)
public class TestEntityRepositoryTests {

	@Autowired
	private TestEntityRepository testEntityRepository;

	@Test
	void test() {
		assertThatThrownBy(() -> testEntityRepository.customSave(new TestEntity()))
				.isInstanceOf(UnsupportedOperationException.class).hasMessage("Not Implemented");
	}

}

Minimal reproducible project: repository-scan.zip

[mp911de]

This is by design. Custom implementations/fragments use two different strategies though:

1. Fragments ($FragmentInterfaceName + $ImplementationPostfix -> Fragment CustomRepository + Impl)
2. Legacy custom implementation ($RepositoryName + $ImplementationPostfix -> Repository Foo + Impl)

Both schemes use the base package as defined in the @Enable…Repositories declaration to detect from bean candidates. Using the base package as filter enables configuration to select different implementations based on the base package.

Fragment implementations must reside in the same package as their fragment interface and fragment implementations must be within one of the specified base packages.

[quaff]

It's a valid use case that reuse fragment repositories as common library share by applications, normally application use different base package name, then @Enable…Repositories must include both base package name and common library base package name, It would be great if we can use @EnableJpaRepositories instead of @EnableJpaRepositories(basePackages={"com.library", "com.application"}), the library fragment repository should be automatic activated if it's extended by application repository.

I propose that $FragmentInterfaceName + $ImplementationPostfix should be default implementation no matter it's in base packages or not, It could be overridden by other implementation in base packages.

Or It should be available if it's registered as spring bean:

package test;

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

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.context.annotation.Bean;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.test.context.ContextConfiguration;

import com.example.demo.CustomRepository;
import com.example.demo.CustomRepositoryImpl;

@DataJpaTest
@EnableJpaRepositories(basePackageClasses = { TestEntityRepository.class })
@EntityScan(basePackageClasses = TestEntity.class)
@ContextConfiguration(classes = TestEntityRepositoryTests.Config.class)
public class TestEntityRepositoryTests {

	@Autowired
	private TestEntityRepository testEntityRepository;

	@Test
	void test() {
		assertThatThrownBy(() -> testEntityRepository.customSave(new TestEntity()))
				.isInstanceOf(UnsupportedOperationException.class).hasMessage("Not Implemented");
	}

	static class Config {
		@Bean
		CustomRepository<?> customRepositoryImpl() {
			return new CustomRepositoryImpl<>();
		}
	}
}

In a nutshell, it's not a good idea that @Enable…Repositories include third party library package name, It should be available if it's on classpath, It's idiomatic in spring boot. WDYT? @mp911de