Merge pull request #29929 from dugenkui03

* pr/29929:
  Polish "Reuse BatchLoaderRegistry in GraphQlService"
  Reuse BatchLoaderRegistry in GraphQlService

Closes gh-29929

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/graphql/GraphQlAutoConfiguration.java

@@ -64,8 +64,6 @@ public class GraphQlAutoConfiguration {
 
 	private static final Log logger = LogFactory.getLog(GraphQlAutoConfiguration.class);
 
-	private final BatchLoaderRegistry batchLoaderRegistry = new DefaultBatchLoaderRegistry();
-
 	@Bean
 	@ConditionalOnMissingBean
 	public GraphQlSource graphQlSource(ResourcePatternResolver resourcePatternResolver, GraphQlProperties properties,
@@ -118,14 +116,14 @@ public class GraphQlAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public BatchLoaderRegistry batchLoaderRegistry() {
-		return this.batchLoaderRegistry;
+		return new DefaultBatchLoaderRegistry();
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
-	public GraphQlService graphQlService(GraphQlSource graphQlSource) {
+	public GraphQlService graphQlService(GraphQlSource graphQlSource, BatchLoaderRegistry batchLoaderRegistry) {
 		ExecutionGraphQlService service = new ExecutionGraphQlService(graphQlSource);
-		service.addDataLoaderRegistrar(this.batchLoaderRegistry);
+		service.addDataLoaderRegistrar(batchLoaderRegistry);
 		return service;
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/graphql/GraphQlAutoConfigurationTests.java

@@ -38,6 +38,7 @@ import org.springframework.graphql.GraphQlService;
 import org.springframework.graphql.data.method.annotation.support.AnnotatedControllerConfigurer;
 import org.springframework.graphql.execution.BatchLoaderRegistry;
 import org.springframework.graphql.execution.DataFetcherExceptionResolver;
+import org.springframework.graphql.execution.DataLoaderRegistrar;
 import org.springframework.graphql.execution.GraphQlSource;
 import org.springframework.graphql.execution.MissingSchemaException;
 import org.springframework.graphql.execution.RuntimeWiringConfigurer;
@@ -169,6 +170,21 @@ class GraphQlAutoConfigurationTests {
 		});
 	}
 
+	@Test
+	void shouldConfigureCustomBatchLoaderRegistry() {
+		this.contextRunner
+				.withBean("customBatchLoaderRegistry", BatchLoaderRegistry.class, () -> mock(BatchLoaderRegistry.class))
+				.run((context) -> {
+					assertThat(context).hasSingleBean(BatchLoaderRegistry.class);
+					assertThat(context.getBean("customBatchLoaderRegistry"))
+							.isSameAs(context.getBean(BatchLoaderRegistry.class));
+					assertThat(context.getBean(GraphQlService.class))
+							.extracting("dataLoaderRegistrars",
+									InstanceOfAssertFactories.list(DataLoaderRegistrar.class))
+							.containsOnly(context.getBean(BatchLoaderRegistry.class));
+				});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class CustomGraphQlBuilderConfiguration {