Fix Liquibase endpoint's output with multiple datasources

Previously, the endpoint used the same change log history service for
for each SpringLiquibase bean that it processed. This resulted in
pollution of the reported changes as the history of each bean was not
isolated.

This commit updates the endpoint to use a new history service for each
SpringLiquibase bean that is processed.

See gh-19171

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/liquibase/LiquibaseEndpoint.java

@@ -63,9 +63,10 @@ public class LiquibaseEndpoint {
 		while (target != null) {
 			Map<String, LiquibaseBean> liquibaseBeans = new HashMap<>();
 			DatabaseFactory factory = DatabaseFactory.getInstance();
-			StandardChangeLogHistoryService service = new StandardChangeLogHistoryService();
-			this.context.getBeansOfType(SpringLiquibase.class)
-					.forEach((name, liquibase) -> liquibaseBeans.put(name, createReport(liquibase, service, factory)));
+			this.context.getBeansOfType(SpringLiquibase.class).forEach((name, liquibase) -> {
+				StandardChangeLogHistoryService service = new StandardChangeLogHistoryService();
+				liquibaseBeans.put(name, createReport(liquibase, service, factory));
+			});
 			ApplicationContext parent = target.getParent();
 			contextBeans.put(target.getId(),
 					new ContextLiquibaseBeans(liquibaseBeans, (parent != null) ? parent.getId() : null));

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/liquibase/LiquibaseEndpointTests.java

@@ -22,6 +22,9 @@ import java.util.Map;
 
 import javax.sql.DataSource;
 
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+import liquibase.integration.spring.SpringLiquibase;
 import org.junit.Test;
 
 import org.springframework.boot.actuate.liquibase.LiquibaseEndpoint.LiquibaseBean;
@@ -41,6 +44,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Eddú Meléndez
  * @author Andy Wilkinson
  * @author Stephane Nicoll
+ * @author Leo Li
  */
 public class LiquibaseEndpointTests {
 
@@ -92,6 +96,20 @@ public class LiquibaseEndpointTests {
 		});
 	}
 
+	@Test
+	public void multipleLiquibaseReportIsReturned() {
+		this.contextRunner.withUserConfiguration(Config.class, LiquibaseConfiguration.class).run((context) -> {
+			Map<String, LiquibaseBean> liquibaseBeans = context.getBean(LiquibaseEndpoint.class).liquibaseBeans()
+					.getContexts().get(context.getId()).getLiquibaseBeans();
+			assertThat(liquibaseBeans.get("liquibase").getChangeSets()).hasSize(1);
+			assertThat(liquibaseBeans.get("liquibase").getChangeSets().get(0).getChangeLog())
+					.isEqualTo("classpath:/db/changelog/db.changelog-master.yaml");
+			assertThat(liquibaseBeans.get("liquibaseBackup").getChangeSets()).hasSize(1);
+			assertThat(liquibaseBeans.get("liquibaseBackup").getChangeSets().get(0).getChangeLog())
+					.isEqualTo("classpath:/db/changelog/db.changelog-master-backup.yaml");
+		});
+	}
+
 	private boolean getAutoCommit(DataSource dataSource) throws SQLException {
 		try (Connection connection = dataSource.getConnection()) {
 			return connection.getAutoCommit();
@@ -108,4 +126,43 @@ public class LiquibaseEndpointTests {
 
 	}
 
+	@Configuration
+	static class LiquibaseConfiguration {
+
+		@Bean
+		DataSource dataSource() {
+			HikariConfig config = new HikariConfig();
+			config.setJdbcUrl("jdbc:hsqldb:mem:test");
+			config.setUsername("sa");
+			return new HikariDataSource(config);
+		}
+
+		@Bean
+		DataSource dataSourceBackup() {
+			HikariConfig config = new HikariConfig();
+			config.setJdbcUrl("jdbc:hsqldb:mem:testBackup");
+			config.setUsername("sa");
+			return new HikariDataSource(config);
+		}
+
+		@Bean
+		SpringLiquibase liquibase(DataSource dataSource) {
+			SpringLiquibase liquibase = new SpringLiquibase();
+			liquibase.setChangeLog("classpath:/db/changelog/db.changelog-master.yaml");
+			liquibase.setShouldRun(true);
+			liquibase.setDataSource(dataSource);
+			return liquibase;
+		}
+
+		@Bean
+		SpringLiquibase liquibaseBackup(DataSource dataSourceBackup) {
+			SpringLiquibase liquibase = new SpringLiquibase();
+			liquibase.setChangeLog("classpath:/db/changelog/db.changelog-master-backup.yaml");
+			liquibase.setShouldRun(true);
+			liquibase.setDataSource(dataSourceBackup);
+			return liquibase;
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator/src/test/resources/db/changelog/db.changelog-master-backup.yaml

+databaseChangeLog:
+  - changeSet:
+      id: 1
+      author: leoli
+      changes:
+        - createTable:
+            tableName: customerbackup
+            columns:
+              - column:
+                  name: id
+                  type: int
+                  autoIncrement: true
+                  constraints:
+                    primaryKey: true
+                    nullable: false
+              - column:
+                  name: name
+                  type: varchar(50)
+                  constraints:
+                    nullable: false