Generate and use constants for pocketmine.yml constant names

a couple of usages of properties that no longer exist couldn't be migrated.
in addition, this revealed a couple of dead properties in the default file.

this is not an ideal solution (I'd much rather model the configs using classes and map them) but in the absence of a good and reliable library to do that, this is the next best thing.

build/generate-pocketmine-yml-property-consts.php

@@ -0,0 +1,76 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+ */
+
+declare(strict_types=1);
+
+use pocketmine\utils\Filesystem;
+use pocketmine\utils\Utils;
+
+require dirname(__DIR__) . '/vendor/autoload.php';
+
+$defaultConfig = yaml_parse(Filesystem::fileGetContents(dirname(__DIR__) . '/resources/pocketmine.yml'));
+
+if(!is_array($defaultConfig)){
+	fwrite(STDERR, "Invalid default pocketmine.yml\n");
+	exit(1);
+}
+
+$constants = [];
+
+/**
+ * @param mixed[] $properties
+ * @param string[] $constants
+ * @phpstan-param array<string, string> $constants
+ * @phpstan-param-out array<string, string> $constants
+ */
+function collectProperties(string $prefix, array $properties, array &$constants) : void{
+	foreach($properties as $propertyName => $property){
+		$fullPropertyName = ($prefix !== "" ? $prefix . "." : "") . $propertyName;
+
+		$constName = str_replace([".", "-"], "_", strtoupper($fullPropertyName));
+		$constants[$constName] = $fullPropertyName;
+
+		if(is_array($property)){
+			collectProperties($fullPropertyName, $property, $constants);
+		}
+	}
+}
+
+collectProperties("", $defaultConfig, $constants);
+ksort($constants, SORT_STRING);
+
+$file = fopen(dirname(__DIR__) . '/src/YmlServerProperties.php', 'wb');
+if($file === false){
+	fwrite(STDERR, "Failed to open output file\n");
+	exit(1);
+}
+fwrite($file, "<?php\n\n");
+fwrite($file, "declare(strict_types=1);\n\n");
+fwrite($file, "namespace pocketmine;\n\n");
+fwrite($file, "final class YmlServerProperties{\n");
+foreach(Utils::stringifyKeys($constants) as $constName => $propertyName){
+	fwrite($file, "\tpublic const $constName = '$propertyName';\n");
+}
+fwrite($file, "}\n");
+
+fclose($file);
+
+echo "Done. Don't forget to run CS fixup after generating code.\n";