PHP: Apply destructor hooks to all class in a .phar file to debug memory leaks

apply_destructor_hooks.php

<?php

declare(strict_types=1);

function apply_destructor_hook(string $contents) : ?string{
	$destructor_body = PHP_EOL;
	$destructor_body .= "echo 'Destroyed ', \$this::class,";
	$destructor_body .= "' (', \spl_object_id(\$this), ')...',";
	$destructor_body .= "\PHP_EOL,";
	$destructor_body .= "(new \Exception)->getTraceAsString(),";
	$destructor_body .= "PHP_EOL;";
	$destructor_body .= PHP_EOL;
	$tokens = PhpToken::tokenize($contents);
	$file_offset = 0; // offset of file contents (when we modify file the succeeding contents are offsetted)
	$offset = 0; // offset of tokens
	$state = "find_class";
	while(isset($tokens[$offset])){
		$token = $tokens[$offset++];
		if($state !== "find_class" && !isset($tokens[$offset])){
			$state = "write_destructor";
		}
		if($state === "find_class"){
			if(isset($tokens[$offset - 2]) && $tokens[$offset - 2]->id === T_DOUBLE_COLON){
				continue;
			}
			if($token->id === T_CLASS){
				$state_class_begin = null;
				$state_existing_destructor = null;
				$state = "find_class_begin";
			}
		}elseif($state === "find_class_begin"){
			if($token->text === "{"){
				$state_class_begin = $token->pos + 1;
				$state = "find_existing_destructor";
			}
		}elseif($state === "find_existing_destructor"){
			if($token->id === T_CLASS){
				$state = "write_destructor";
			}elseif($token->id === T_FUNCTION){
				$state = "check_if_destructor";
			}
		}elseif($state === "check_if_destructor"){
			if($token->id === T_STRING && $token->text === "__destruct"){
				$state = "find_existing_destructor_begin";
			}
		}elseif($state === "find_existing_destructor_begin"){
			if($token->text === "{"){
				$state_existing_destructor = $token->pos + 1;
				$state = "write_destructor";
			}
		}elseif($state === "write_destructor"){
			if($state_existing_destructor !== null){
				$contents = (string) substr_replace($contents, $destructor_body, $state_existing_destructor + $file_offset, 0);
				$file_offset += strlen($destructor_body);
			}elseif($state_class_begin !== null){
				$body = PHP_EOL . "public function __destruct(){{$destructor_body}}" . PHP_EOL;
				$contents = (string) substr_replace($contents, $body, $state_class_begin + $file_offset, 0);
				$file_offset += strlen($body);
			}
			$state = "find_class";
		}
	}
	return $file_offset > 0 ? $contents : null;
}

function apply_destructor_hooks(string $path, array $ignored_path_matcher) : void{
	/** @var SplFileInfo $file */
	foreach(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path)) as $file){
		if($file->getExtension() !== "php"){
			continue;
		}
		$path = $file->getPathname();
		foreach($ignored_path_matcher as $ignored_path){
			if(fnmatch($ignored_path, $path)){
				continue 2;
			}
		}
		$contents = file_get_contents($path);
		$contents !== false || throw new RuntimeException("Failed to read file: {$path}");
		$contents = apply_destructor_hook($contents);
		if($contents !== null){
			file_put_contents($path, $contents);
			//echo "Changed ", $path, PHP_EOL;
		}else{
			//echo "No changes for ", $path, PHP_EOL;
		}
	}
}

$path = $argv[1];
try{
	$phar = new Phar($path);
}catch(UnexpectedValueException){
	echo "Cannot open phar file: ", $path, PHP_EOL;
	exit(1);
}

$current_dir = getcwd();
$current_dir !== false || throw new RuntimeException("Failed to get current directory");
$temp_dir = tempnam($current_dir, "apply-destructor-hooks-");
unlink($temp_dir) || throw new RuntimeException("Failed to create temp path");
mkdir($temp_dir) || throw new RuntimeException("Failed to create temp path");
$phar->extractTo($temp_dir);
apply_destructor_hooks($temp_dir, [
	"*Task.php",
	"*ResourcePack*.php",
	"*AwaitGenerator*",
	"*cosmicpe\\config\\*"
]);

echo "Extracted to ", $temp_dir, PHP_EOL;
echo "Building phar...", PHP_EOL;
$out = new Phar($temp_dir . ".phar");
$out->startBuffering();
$out->buildFromDirectory($temp_dir);
$out->stopBuffering();
try{
	$out->compressFiles(Phar::GZ);
}catch(BadMethodCallException){}
echo "Phar written to ", $temp_dir, ".phar", PHP_EOL;

Usage:

php apply_destructor_hooks.php /path/to/myproject.phar

Example output:

Destroyed cosmicpe\world\region\flag\handler\utils\PriorityRegionMap (1099639)...
#0 phar:///home/cosmicpe/spirit/plugins/CosmicPE_v0.0.3.phar/src/cosmicpe/world/WorldInstance.php(173): cosmicpe\world\region\flag\handler\utils\PriorityRegionMap->__destruct()
#1 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/scheduler/ClosureTask.php(57): cosmicpe\world\WorldInstance->cosmicpe\world\{closure}()
#2 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/scheduler/TaskHandler.php(122): pocketmine\scheduler\ClosureTask->onRun()
#3 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/scheduler/TaskScheduler.php(175): pocketmine\scheduler\TaskHandler->run()
#4 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/plugin/PluginManager.php(540): pocketmine\scheduler\TaskScheduler->mainThreadHeartbeat(2401)
#5 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/Server.php(1841): pocketmine\plugin\PluginManager->tickSchedulers(2401)
#6 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/Server.php(1730): pocketmine\Server->tick()
#7 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/Server.php(1097): pocketmine\Server->tickProcessor()
#8 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/PocketMine.php(355): pocketmine\Server->__construct(Object(pocketmine\thread\ThreadSafeClassLoader), Object(pocketmine\utils\MainLogger), '/home/cosmicpe/...', '/home/cosmicpe/...')
#9 phar:///tmp/PocketMine-MP-phar-cache.0/PMMPbkY9B0.tar/src/PocketMine.php(378): pocketmine\server()
#10 /home/cosmicpe/spirit/PocketMine-MP.phar(168): require('phar:///tmp/Poc...')
#11 {main}