DATACMNS-542 - Be more lenient about simplified way to customize repository base classes.

We now leniently return null for the repository base class name from the AnnotationRepositoryConfigurationSource to make sure Spring Data modules compile against Spring Data Commons 1.10 continue to work on 1.11 without having the annotation attribute added.

src/main/java/org/springframework/data/repository/config/AnnotationRepositoryConfigurationSource.java

@@ -221,6 +221,10 @@ public class AnnotationRepositoryConfigurationSource extends RepositoryConfigura
 	@Override
 	public String getRepositoryBaseClassName() {
 
+		if (!attributes.containsKey(REPOSITORY_BASE_CLASS)) {
+			return null;
+		}
+
 		Class<? extends Object> repositoryBaseClass = attributes.getClass(REPOSITORY_BASE_CLASS);
 		return DefaultRepositoryBaseClass.class.equals(repositoryBaseClass) ? null : repositoryBaseClass.getName();
 	}

src/test/java/org/springframework/data/repository/config/AnnotationRepositoryConfigurationSourceUnitTests.java

@@ -18,6 +18,8 @@ package org.springframework.data.repository.config;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.util.Collection;
 
 import org.junit.Before;
@@ -146,6 +148,19 @@ public class AnnotationRepositoryConfigurationSourceUnitTests {
 		assertThat(getConfigSource(DefaultConfiguration.class).usesExplicitFilters(), is(false));
 	}
 
+	/**
+	 * @see DATACMNS-542
+	 */
+	@Test
+	public void ignoresMissingRepositoryBaseClassNameAttribute() {
+
+		AnnotationMetadata metadata = new StandardAnnotationMetadata(ConfigWithSampleAnnotation.class, true);
+		RepositoryConfigurationSource configurationSource = new AnnotationRepositoryConfigurationSource(metadata,
+				SampleAnnotation.class, resourceLoader, environment);
+
+		assertThat(configurationSource.getRepositoryBaseClassName(), is(nullValue()));
+	}
+
 	private AnnotationRepositoryConfigurationSource getConfigSource(Class<?> type) {
 
 		AnnotationMetadata metadata = new StandardAnnotationMetadata(type, true);
@@ -165,4 +180,15 @@ public class AnnotationRepositoryConfigurationSourceUnitTests {
 
 	@EnableRepositories(excludeFilters = { @Filter(Primary.class) })
 	static class ConfigurationWithExplicitFilter {}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface SampleAnnotation {
+
+		Filter[] includeFilters() default {};
+
+		Filter[] excludeFilters() default {};
+	}
+
+	@SampleAnnotation
+	static class ConfigWithSampleAnnotation {}
 }