addresses #33748 validate default table on jdbc session init

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/JdbcSessionDataSourceScriptDatabaseInitializer.java

@@ -17,10 +17,12 @@
 package org.springframework.boot.autoconfigure.session;
 
 import java.util.List;
+import java.util.Objects;
 
 import javax.sql.DataSource;
 
 import org.springframework.boot.jdbc.DatabaseDriver;
+import org.springframework.boot.context.properties.source.InvalidConfigurationPropertyValueException;
 import org.springframework.boot.jdbc.init.DataSourceScriptDatabaseInitializer;
 import org.springframework.boot.jdbc.init.PlatformPlaceholderDatabaseDriverResolver;
 import org.springframework.boot.sql.init.DatabaseInitializationSettings;
@@ -38,6 +40,8 @@
  */
 public class JdbcSessionDataSourceScriptDatabaseInitializer extends DataSourceScriptDatabaseInitializer {
 
+	private JdbcSessionProperties properties;
+
 	/**
 	 * Create a new {@link JdbcSessionDataSourceScriptDatabaseInitializer} instance.
 	 * @param dataSource the Spring Session JDBC data source
@@ -46,6 +50,7 @@ public class JdbcSessionDataSourceScriptDatabaseInitializer extends DataSourceSc
 	 */
 	public JdbcSessionDataSourceScriptDatabaseInitializer(DataSource dataSource, JdbcSessionProperties properties) {
 		this(dataSource, getSettings(dataSource, properties));
+		this.properties = properties;
 	}
 
 	/**
@@ -77,6 +82,34 @@ static DatabaseInitializationSettings getSettings(DataSource dataSource, JdbcSes
 		return settings;
 	}
 
+	@Override
+	protected void runScripts(Scripts scripts) {
+		validateConfiguration();
+		super.runScripts(scripts);
+	}
+
+	void validateConfiguration() {
+		if (properties == null) return; // cannot validate without this
+		JdbcSessionProperties defaults = new JdbcSessionProperties();
+		boolean willHappen = switch (properties.getInitializeSchema()) {
+			case ALWAYS -> true;
+			case NEVER -> false;
+			case EMBEDDED -> isEmbeddedDatabase();
+		};
+		boolean tableNameChanged = !Objects.equals(defaults.getTableName(), properties.getTableName());
+		boolean schemaUnchanged = Objects.equals(defaults.getSchema(), properties.getSchema());
+
+		if (willHappen && tableNameChanged && schemaUnchanged) {
+			String name = "spring.session.jdbc.schema";
+			String value = properties.getSchema();
+			String reason = "When JDBC Session database initialization will take place " +
+					"(spring.session.jdbc.initialize-schema = " + properties.getInitializeSchema() + "), " +
+					"and the table name is not the default value (" + properties.getTableName() + "), " +
+					"the schema must be a custom schema to match the specified table name.";
+			throw new InvalidConfigurationPropertyValueException(name, value, reason);
+		}
+	}
+
 	private static List<String> resolveSchemaLocations(DataSource dataSource, JdbcSessionProperties properties) {
 		PlatformPlaceholderDatabaseDriverResolver platformResolver = new PlatformPlaceholderDatabaseDriverResolver();
 		platformResolver = platformResolver.withDriverPlatform(DatabaseDriver.MARIADB, "mysql");

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/session/JdbcSessionDataSourceScriptDatabaseInitializerTests.java

@@ -20,9 +20,12 @@
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.sql.init.DatabaseInitializationMode;
 import org.springframework.boot.sql.init.DatabaseInitializationSettings;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
 import static org.mockito.BDDMockito.then;
 import static org.mockito.Mockito.mock;
 
@@ -45,4 +48,29 @@ void getSettingsWithPlatformDoesNotTouchDataSource() {
 		then(dataSource).shouldHaveNoInteractions();
 	}
 
+	@Test
+	void test_validateConfigurationThrowsForInvalidConfiguration() {
+		DataSource dataSource = mock(DataSource.class);
+		JdbcSessionProperties properties = new JdbcSessionProperties();
+		properties.setPlatform("mysql");
+		JdbcSessionDataSourceScriptDatabaseInitializer initializer =
+				new JdbcSessionDataSourceScriptDatabaseInitializer(dataSource, properties) {
+					@Override
+					protected boolean isEmbeddedDatabase() {
+						return false;
+					}
+				};
+
+		assertThatCode(initializer::validateConfiguration).doesNotThrowAnyException();
+
+		properties.setInitializeSchema(DatabaseInitializationMode.ALWAYS);
+		assertThatCode(initializer::validateConfiguration).doesNotThrowAnyException();
+
+		properties.setTableName(properties.getTableName() + "_CUSTOM");
+		assertThatThrownBy(initializer::validateConfiguration).message().isNotBlank();
+
+		properties.setSchema(properties.getSchema() + ".different.sql");
+		assertThatCode(initializer::validateConfiguration).doesNotThrowAnyException();
+	}
+
 }