migrations: refuse to apply empty schema files

classes/db/migrations.php

@@ -82,11 +82,14 @@ class Db_Migrations {
 			else
 				Debug::log("Starting migration to $version...", Debug::LOG_VERBOSE);
 
+			$lines = $this->get_lines($version);
+
+			if (count($lines) > 0) {
 				// mysql doesn't support transactions for DDL statements
 				if (Config::get(Config::DB_TYPE) != "mysql")
 					$this->pdo->beginTransaction();
 
-			foreach ($this->get_lines($version) as $line) {
+				foreach ($lines as $line) {
 					Debug::log($line, Debug::LOG_EXTENDED);
 					try {
 						$this->pdo->query($line);
@@ -105,6 +108,9 @@ class Db_Migrations {
 					$this->pdo->commit();
 
 				Debug::log("Migration finished, current version: " . $this->get_version(), Debug::LOG_VERBOSE);
+			} else {
+				Debug::log("Migration failed: schema file is empty or missing.", Debug::LOG_VERBOSE);
+			}
 
 		} catch (PDOException $e) {
 			Debug::log("Migration failed: " . $e->getMessage(), Debug::LOG_VERBOSE);