Harmonize configuration of Flyway SQL Server extension

Closes gh-36440

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration.java

@@ -141,6 +141,12 @@ public class FlywayAutoConfiguration {
 			return new PropertiesFlywayConnectionDetails(this.properties);
 		}
 
+		@Bean
+		@ConditionalOnClass(name = "org.flywaydb.database.sqlserver.SQLServerConfigurationExtension")
+		SqlServerFlywayConfigurationCustomizer sqlServerFlywayConfigurationCustomizer() {
+			return new SqlServerFlywayConfigurationCustomizer(this.properties);
+		}
+
 		@Bean
 		@ConditionalOnClass(name = "org.flywaydb.database.oracle.OracleConfigurationExtension")
 		OracleFlywayConfigurationCustomizer oracleFlywayConfigurationCustomizer() {
@@ -267,10 +273,6 @@ public class FlywayAutoConfiguration {
 			map.from(properties.getJdbcProperties()).whenNot(Map::isEmpty).to(configuration::jdbcProperties);
 			map.from(properties.getKerberosConfigFile()).to(configuration::kerberosConfigFile);
 			map.from(properties.getOutputQueryResults()).to(configuration::outputQueryResults);
-			map.from(properties.getSqlServerKerberosLoginFile())
-				.whenNonNull()
-				.to((sqlServerKerberosLoginFile) -> configureSqlServerKerberosLoginFile(configuration,
-						sqlServerKerberosLoginFile));
 			map.from(properties.getSkipExecutingMigrations()).to(configuration::skipExecutingMigrations);
 			map.from(properties.getIgnoreMigrationPatterns())
 				.whenNot(List::isEmpty)
@@ -289,14 +291,6 @@ public class FlywayAutoConfiguration {
 			}
 		}
 
-		private void configureSqlServerKerberosLoginFile(FluentConfiguration configuration,
-				String sqlServerKerberosLoginFile) {
-			SQLServerConfigurationExtension sqlServerConfigurationExtension = configuration.getPluginRegister()
-				.getPlugin(SQLServerConfigurationExtension.class);
-			Assert.state(sqlServerConfigurationExtension != null, "Flyway SQL Server extension missing");
-			sqlServerConfigurationExtension.getKerberos().getLogin().setFile(sqlServerKerberosLoginFile);
-		}
-
 		private void configureCallbacks(FluentConfiguration configuration, List<Callback> callbacks) {
 			if (!callbacks.isEmpty()) {
 				configuration.callbacks(callbacks.toArray(new Callback[0]));
@@ -484,6 +478,31 @@ public class FlywayAutoConfiguration {
 
 	}
 
+	@Order(Ordered.HIGHEST_PRECEDENCE)
+	static final class SqlServerFlywayConfigurationCustomizer implements FlywayConfigurationCustomizer {
+
+		private final FlywayProperties properties;
+
+		SqlServerFlywayConfigurationCustomizer(FlywayProperties properties) {
+			this.properties = properties;
+		}
+
+		@Override
+		public void customize(FluentConfiguration configuration) {
+			ConfigurationExtensionMapper<SQLServerConfigurationExtension> map = new ConfigurationExtensionMapper<>(
+					PropertyMapper.get().alwaysApplyingWhenNonNull(), () -> {
+						SQLServerConfigurationExtension extension = configuration.getPluginRegister()
+							.getPlugin(SQLServerConfigurationExtension.class);
+						Assert.notNull(extension, "Flyway SQL Server extension missing");
+						return extension;
+					});
+
+			map.apply(this.properties.getSqlServerKerberosLoginFile(),
+					(extension, file) -> extension.getKerberos().getLogin().setFile(file));
+		}
+
+	}
+
 	static class ConfigurationExtensionMapper<T extends ConfigurationExtension> {
 
 		private final PropertyMapper map;

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfigurationTests.java

@@ -52,6 +52,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.FlywayAutoConfigurationRuntimeHints;
 import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.OracleFlywayConfigurationCustomizer;
+import org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration.SqlServerFlywayConfigurationCustomizer;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
 import org.springframework.boot.autoconfigure.jdbc.EmbeddedDataSourceConfiguration;
 import org.springframework.boot.autoconfigure.jdbc.JdbcConnectionDetails;
@@ -732,6 +733,13 @@ class FlywayAutoConfigurationTests {
 			.run(validateFlywayTeamsPropertyOnly("outputQueryResults"));
 	}
 
+	@Test
+	void sqlServerExtensionIsNotLoadedByDefault() {
+		FluentConfiguration configuration = mock(FluentConfiguration.class);
+		new SqlServerFlywayConfigurationCustomizer(new FlywayProperties()).customize(configuration);
+		then(configuration).shouldHaveNoInteractions();
+	}
+
 	@Test
 	void sqlServerKerberosLoginFileIsCorrectlyMapped() {
 		this.contextRunner.withUserConfiguration(EmbeddedDataSourceConfiguration.class)