Add nullability annotations to module/spring-boot-flyway

See gh-46587

Author: mhalbritter

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

@@ -38,6 +38,7 @@
 import org.flywaydb.database.oracle.OracleConfigurationExtension;
 import org.flywaydb.database.postgresql.PostgreSQLConfigurationExtension;
 import org.flywaydb.database.sqlserver.SQLServerConfigurationExtension;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
@@ -177,14 +178,14 @@ Flyway flyway(FlywayConnectionDetails connectionDetails, ResourceLoader resource
 			return configuration.load();
 		}
 
-		private void configureDataSource(FluentConfiguration configuration, DataSource flywayDataSource,
-				DataSource dataSource, FlywayConnectionDetails connectionDetails) {
+		private void configureDataSource(FluentConfiguration configuration, @Nullable DataSource flywayDataSource,
+				@Nullable DataSource dataSource, FlywayConnectionDetails connectionDetails) {
 			DataSource migrationDataSource = getMigrationDataSource(flywayDataSource, dataSource, connectionDetails);
 			configuration.dataSource(migrationDataSource);
 		}
 
-		private DataSource getMigrationDataSource(DataSource flywayDataSource, DataSource dataSource,
-				FlywayConnectionDetails connectionDetails) {
+		private DataSource getMigrationDataSource(@Nullable DataSource flywayDataSource,
+				@Nullable DataSource dataSource, FlywayConnectionDetails connectionDetails) {
 			if (flywayDataSource != null) {
 				return flywayDataSource;
 			}
@@ -424,7 +425,7 @@ public Set<ConvertiblePair> getConvertibleTypes() {
 		}
 
 		@Override
-		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+		public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			String value = ObjectUtils.nullSafeToString(source);
 			return MigrationVersion.fromVersion(value);
 		}
@@ -457,7 +458,7 @@ private static final class FlywayUrlCondition {
 	static class FlywayAutoConfigurationRuntimeHints implements RuntimeHintsRegistrar {
 
 		@Override
-		public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+		public void registerHints(RuntimeHints hints, @Nullable ClassLoader classLoader) {
 			hints.resources().registerPattern("db/migration/*");
 		}
 
@@ -475,22 +476,22 @@ static final class PropertiesFlywayConnectionDetails implements FlywayConnection
 		}
 
 		@Override
-		public String getUsername() {
+		public @Nullable String getUsername() {
 			return this.properties.getUser();
 		}
 
 		@Override
-		public String getPassword() {
+		public @Nullable String getPassword() {
 			return this.properties.getPassword();
 		}
 
 		@Override
-		public String getJdbcUrl() {
+		public @Nullable String getJdbcUrl() {
 			return this.properties.getUrl();
 		}
 
 		@Override
-		public String getDriverClassName() {
+		public @Nullable String getDriverClassName() {
 			return this.properties.getDriverClassName();
 		}
 
@@ -574,7 +575,7 @@ private void setKerberosLoginFile(SQLServerConfigurationExtension configuration,
 	 */
 	static class Extension<E extends ConfigurationExtension> {
 
-		private SingletonSupplier<E> extension;
+		private final SingletonSupplier<E> extension;
 
 		Extension(FluentConfiguration configuration, Class<E> type, String name) {
 			this.extension = SingletonSupplier.of(() -> {

module/spring-boot-flyway/src/main/java/org/springframework/boot/flyway/autoconfigure/FlywayConnectionDetails.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.flyway.autoconfigure;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.autoconfigure.service.connection.ConnectionDetails;
 import org.springframework.boot.jdbc.DatabaseDriver;
 
@@ -32,21 +34,21 @@ public interface FlywayConnectionDetails extends ConnectionDetails {
 	 * required.
 	 * @return the username for the database or {@code null}
 	 */
-	String getUsername();
+	@Nullable String getUsername();
 
 	/**
 	 * Password for the database or {@code null} if no Flyway-specific configuration is
 	 * required.
 	 * @return the password for the database or {@code null}
 	 */
-	String getPassword();
+	@Nullable String getPassword();
 
 	/**
 	 * JDBC URL for the database or {@code null} if no Flyway-specific configuration is
 	 * required.
 	 * @return the JDBC URL for the database or {@code null}
 	 */
-	String getJdbcUrl();
+	@Nullable String getJdbcUrl();
 
 	/**
 	 * The name of the JDBC driver class. Defaults to the class name of the driver
@@ -56,7 +58,7 @@ public interface FlywayConnectionDetails extends ConnectionDetails {
 	 * @see DatabaseDriver#fromJdbcUrl(String)
 	 * @see DatabaseDriver#getDriverClassName()
 	 */
-	default String getDriverClassName() {
+	default @Nullable String getDriverClassName() {
 		String jdbcUrl = getJdbcUrl();
 		return (jdbcUrl != null) ? DatabaseDriver.fromJdbcUrl(jdbcUrl).getDriverClassName() : null;
 	}

module/spring-boot-flyway/src/main/java/org/springframework/boot/flyway/autoconfigure/FlywayMigrationInitializer.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.flyway.autoconfigure;
 
 import org.flywaydb.core.Flyway;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.core.Ordered;
@@ -33,7 +34,7 @@ public class FlywayMigrationInitializer implements InitializingBean, Ordered {
 
 	private final Flyway flyway;
 
-	private final FlywayMigrationStrategy migrationStrategy;
+	private final @Nullable FlywayMigrationStrategy migrationStrategy;
 
 	private int order = 0;
 
@@ -50,7 +51,7 @@ public FlywayMigrationInitializer(Flyway flyway) {
 	 * @param flyway the flyway instance
 	 * @param migrationStrategy the migration strategy or {@code null}
 	 */
-	public FlywayMigrationInitializer(Flyway flyway, FlywayMigrationStrategy migrationStrategy) {
+	public FlywayMigrationInitializer(Flyway flyway, @Nullable FlywayMigrationStrategy migrationStrategy) {
 		Assert.notNull(flyway, "'flyway' must not be null");
 		this.flyway = flyway;
 		this.migrationStrategy = migrationStrategy;