Polish "Add liquibase driver class name property"

See gh-23958

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseAutoConfiguration.java

@@ -54,6 +54,7 @@ import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
 import org.springframework.jdbc.datasource.SimpleDriverDataSource;
 import org.springframework.orm.jpa.AbstractEntityManagerFactoryBean;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.util.StringUtils;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for Liquibase.
@@ -148,8 +149,19 @@ public class LiquibaseAutoConfiguration {
 			String url = getProperty(this.properties::getUrl, dataSourceProperties::determineUrl);
 			String user = getProperty(this.properties::getUser, dataSourceProperties::determineUsername);
 			String password = getProperty(this.properties::getPassword, dataSourceProperties::determinePassword);
+			String driverClassName = determineDriverClassName(dataSourceProperties, url);
 			return DataSourceBuilder.create().type(determineDataSourceType()).url(url).username(user).password(password)
-					.driverClassName(determineDriverClassName(url)).build();
+					.driverClassName(driverClassName).build();
+		}
+
+		private String determineDriverClassName(DataSourceProperties dataSourceProperties, String url) {
+			if (StringUtils.hasText(this.properties.getDriverClassName())) {
+				return this.properties.getDriverClassName();
+			}
+			if (StringUtils.hasText(dataSourceProperties.getDriverClassName())) {
+				return dataSourceProperties.getDriverClassName();
+			}
+			return StringUtils.hasText(url) ? DatabaseDriver.fromJdbcUrl(url).getDriverClassName() : null;
 		}
 
 		private Class<? extends DataSource> determineDataSourceType() {
@@ -157,11 +169,6 @@ public class LiquibaseAutoConfiguration {
 			return (type != null) ? type : SimpleDriverDataSource.class;
 		}
 
-		private String determineDriverClassName(String url) {
-			String driverClassName = this.properties.getDriverClassName();
-			return (driverClassName != null) ? driverClassName : DatabaseDriver.fromJdbcUrl(url).getDriverClassName();
-		}
-
 		private String getProperty(Supplier<String> property, Supplier<String> defaultValue) {
 			String value = property.get();
 			return (value != null) ? value : defaultValue.get();

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/liquibase/LiquibaseAutoConfigurationTests.java

@@ -243,6 +243,21 @@ class LiquibaseAutoConfigurationTests {
 				}));
 	}
 
+	@Test
+	void overrideDataSourceWithFallbackDriverClassName() {
+		String jdbcUrl = "jdbc:hsqldb:mem:liquibase";
+		String driverClassName = "org.hsqldb.jdbcDriver";
+		this.contextRunner.withUserConfiguration(EmbeddedDataSourceConfiguration.class)
+				.withPropertyValues("spring.liquibase.url:" + jdbcUrl,
+						"spring.datasource.driver-class-name:" + driverClassName)
+				.run(assertLiquibase((liquibase) -> {
+					DataSource dataSource = liquibase.getDataSource();
+					assertThat(((HikariDataSource) dataSource).isClosed()).isTrue();
+					assertThat(((HikariDataSource) dataSource).getJdbcUrl()).isEqualTo(jdbcUrl);
+					assertThat(((HikariDataSource) dataSource).getDriverClassName()).isEqualTo(driverClassName);
+				}));
+	}
+
 	@Test
 	void overrideUser() {
 		String jdbcUrl = "jdbc:hsqldb:mem:normal";

spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto.adoc

@@ -2217,7 +2217,7 @@ In addition to YAML, Liquibase also supports JSON, XML, and SQL change log forma
 By default, Liquibase autowires the (`@Primary`) `DataSource` in your context and uses that for migrations.
 If you need to use a different `DataSource`, you can create one and mark its `@Bean` as `@LiquibaseDataSource`.
 If you do so and you want two data sources, remember to create another one and mark it as `@Primary`.
-Alternatively, you can use Liquibase's native `DataSource` by setting `spring.liquibase.[url,user,password]` in external properties.
+Alternatively, you can use Liquibase's native `DataSource` by setting `spring.liquibase.[driver-class-name,url,user,password]` in external properties.
 Setting either `spring.liquibase.url` or `spring.liquibase.user` is sufficient to cause Liquibase to use its own `DataSource`.
 If any of the three properties has not been set, the value of its equivalent `spring.datasource` property will be used.