Locate & parse phpstan config to determine tmpDir

To make sure that the cached files are generated in the
same cache directory as the regular phpstan files, find
the phpstan configuration and parse it via Nette\Neon
parser. Downside: The configuration gets parsed twice but
I did not notice any bigger speed difference.

autoload.php

@@ -13,11 +13,43 @@
 use bitExpert\PHPStan\Magento\Autoload\FactoryAutoloader;
 use bitExpert\PHPStan\Magento\Autoload\MockAutoloader;
 use bitExpert\PHPStan\Magento\Autoload\ProxyAutoloader;
+use Nette\Neon\Neon;
 use PHPStan\Cache\Cache;
 
 // This autoloader implementation supersedes the former \bitExpert\PHPStan\Magento\Autoload\Autoload implementation
-(function () {
-    $cache = new Cache(new FileCacheStorage(sys_get_temp_dir() . '/phpstan/cache/PHPStan'));
+(function (array $argv = []) {
+    // Sadly we don't have access to the parsed phpstan.neon configuration at this point we need to look up the
+    // location of the config file and parse it with the Neon parser to be able to extract the tmpDir definition!
+    $configFile = '';
+    if (count($argv) > 0) {
+        foreach($argv as $idx => $value) {
+            if ((strtolower($value) === '-c') && isset($argv[$idx + 1])) {
+                $configFile = $argv[$idx + 1];
+                break;
+            }
+        }
+    }
+
+    if (empty($configFile)) {
+        $currentWorkingDirectory = getcwd();
+        foreach (['phpstan.neon', 'phpstan.neon.dist'] as $discoverableConfigName) {
+            $discoverableConfigFile = $currentWorkingDirectory . DIRECTORY_SEPARATOR . $discoverableConfigName;
+            if (file_exists($discoverableConfigFile) && is_readable(($discoverableConfigFile))) {
+                $configFile = $discoverableConfigFile;
+                break;
+            }
+        }
+    }
+
+    $tmpDir = sys_get_temp_dir() . '/phpstan';
+    if (!empty($configFile)) {
+        $neonConfig = Neon::decode(file_get_contents($configFile));
+        if(is_array($neonConfig) && isset($neonConfig['parameters']) && isset($neonConfig['parameters']['tmpDir'])) {
+            $tmpDir = $neonConfig['parameters']['tmpDir'];
+        }
+    }
+
+    $cache = new Cache(new FileCacheStorage($tmpDir . '/cache/PHPStan'));
 
     $mockAutoloader = new MockAutoloader();
     $factoryAutoloader = new FactoryAutoloader($cache);
@@ -26,4 +58,4 @@
     \spl_autoload_register([$mockAutoloader, 'autoload'], true, true);
     \spl_autoload_register([$factoryAutoloader, 'autoload'], true, false);
     \spl_autoload_register([$proxyAutoloader, 'autoload'], true, false);
-})();
+})($GLOBALS['argv'] ?? []);

composer.json

@@ -17,6 +17,7 @@
   ],
   "require": {
     "php": "^7.2.0",
+    "nette/neon": "^3.1",
     "phpstan/phpstan": "^0.12.18"
   },
   "require-dev": {