From 612e9e162ca4f7be67c62eef33ffe3d2737e359d Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Sat, 6 Apr 2019 15:17:36 +0100
Subject: [PATCH] Fixed worlds with unknown generators silently getting wrong
 generator, closes #2860

---
 src/pocketmine/Server.php                          | 14 ++++++++++++--
 src/pocketmine/level/Level.php                     |  2 +-
 .../level/generator/GeneratorManager.php           |  7 ++++++-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/pocketmine/Server.php b/src/pocketmine/Server.php
index acdc1bc4b..c5911d8b8 100644
--- a/src/pocketmine/Server.php
+++ b/src/pocketmine/Server.php
@@ -1091,9 +1091,19 @@ class Server{
 
 			return false;
 		}
+		/**
+		 * @var LevelProvider $provider
+		 * @see LevelProvider::__construct()
+		 */
+		$provider = new $providerClass($path);
+		try{
+			GeneratorManager::getGenerator($provider->getGenerator(), true);
+		}catch(\InvalidArgumentException $e){
+			$this->logger->error($this->getLanguage()->translateString("pocketmine.level.loadError", [$name, "Unknown generator \"" . $provider->getGenerator() . "\""]));
+			return false;
+		}
 
-		/** @see LevelProvider::__construct() */
-		$level = new Level($this, $name, new $providerClass($path));
+		$level = new Level($this, $name, $provider);
 
 		$this->levels[$level->getId()] = $level;
 
diff --git a/src/pocketmine/level/Level.php b/src/pocketmine/level/Level.php
index 306733035..70285fb62 100644
--- a/src/pocketmine/level/Level.php
+++ b/src/pocketmine/level/Level.php
@@ -383,7 +383,7 @@ class Level implements ChunkManager, Metadatable{
 		$this->worldHeight = $this->provider->getWorldHeight();
 
 		$this->server->getLogger()->info($this->server->getLanguage()->translateString("pocketmine.level.preparing", [$this->displayName]));
-		$this->generator = GeneratorManager::getGenerator($this->provider->getGenerator());
+		$this->generator = GeneratorManager::getGenerator($this->provider->getGenerator(), true);
 		//TODO: validate generator options
 
 		$this->folderName = $name;
diff --git a/src/pocketmine/level/generator/GeneratorManager.php b/src/pocketmine/level/generator/GeneratorManager.php
index 5e24b1faa..013fe9031 100644
--- a/src/pocketmine/level/generator/GeneratorManager.php
+++ b/src/pocketmine/level/generator/GeneratorManager.php
@@ -74,14 +74,19 @@ final class GeneratorManager{
 	 * Returns a class name of a registered Generator matching the given name.
 	 *
 	 * @param string $name
+	 * @param bool   $throwOnMissing @deprecated this is for backwards compatibility only
 	 *
 	 * @return string|Generator Name of class that extends Generator (not an actual Generator object)
+	 * @throws \InvalidArgumentException if the generator type isn't registered
 	 */
-	public static function getGenerator(string $name){
+	public static function getGenerator(string $name, bool $throwOnMissing = false){
 		if(isset(self::$list[$name = strtolower($name)])){
 			return self::$list[$name];
 		}
 
+		if($throwOnMissing){
+			throw new \InvalidArgumentException("Alias \"$name\" does not map to any known generator");
+		}
 		return Normal::class;
 	}