Add @ConditionalOnMissingBean for JobRepository

Update `BatchAutoConfiguration` so that the `JobRepository` is not
defined when the user provides an appropriate bean.

Fixes gh-43236

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfiguration.java

@@ -20,6 +20,7 @@
 
 import javax.sql.DataSource;
 
+import org.springframework.batch.core.configuration.BatchConfigurationException;
 import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
 import org.springframework.batch.core.configuration.support.DefaultBatchConfiguration;
 import org.springframework.batch.core.explore.JobExplorer;
@@ -129,6 +130,13 @@ protected DataSource getDataSource() {
 			return this.dataSource;
 		}
 
+		@Bean
+		@ConditionalOnMissingBean
+		@Override
+		public JobRepository jobRepository() throws BatchConfigurationException {
+			return super.jobRepository();
+		}
+
 		@Override
 		protected PlatformTransactionManager getTransactionManager() {
 			return this.transactionManager;

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/batch/BatchAutoConfigurationTests.java

@@ -517,6 +517,13 @@ void defaultExecutionContextSerializerIsUsed() {
 			});
 	}
 
+	@Test
+	void defaultJobRepositoryIsNotCreatedWhenUserDefinedJobRepositoryBean() {
+		this.contextRunner
+			.withUserConfiguration(TestConfigurationWithJobRepository.class, EmbeddedDataSourceConfiguration.class)
+			.run((context) -> assertThat(context).hasSingleBean(TestJobRepository.class));
+	}
+
 	private JobLauncherApplicationRunner createInstance(String... registeredJobNames) {
 		JobLauncherApplicationRunner runner = new JobLauncherApplicationRunner(mock(JobLauncher.class),
 				mock(JobExplorer.class), mock(JobRepository.class));
@@ -596,6 +603,16 @@ static class TestConfiguration {
 
 	}
 
+	@TestAutoConfigurationPackage(City.class)
+	static class TestConfigurationWithJobRepository {
+
+		@Bean
+		TestJobRepository jobRepository() {
+			return mock(TestJobRepository.class);
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class EntityManagerFactoryConfiguration {
 
@@ -880,4 +897,8 @@ ExecutionContextSerializer executionContextSerializer() {
 
 	}
 
+	interface TestJobRepository extends JobRepository {
+
+	}
+
 }