add suggested fix from copilot

Author: paulbalandan

system/Autoloader/Autoloader.php

@@ -93,6 +93,12 @@ class Autoloader
      */
     protected $helpers = ['url'];
 
+    /**
+     * Track whether Composer namespaces have been loaded to prevent
+     * re-loading in parallel test execution contexts.
+     */
+    private bool $composerNamespacesLoaded = false;
+
     public function __construct(private readonly string $composerPath = COMPOSER_PATH)
     {
     }
@@ -109,6 +115,8 @@ public function initialize(Autoload $config, Modules $modules)
         $this->classmap = [];
         $this->files    = [];
 
+        $this->composerNamespacesLoaded = false;
+
         // We have to have one or the other, though we don't enforce the need
         // to have both present in order to work.
         if ($config->psr4 === [] && $config->classmap === []) {
@@ -150,9 +158,11 @@ private function loadComposerAutoloader(Modules $modules): void
         $composer = include $this->composerPath;
 
         // Should we load through Composer's namespaces, also?
-        if ($modules->discoverInComposer) {
+        // Guard against repeated loading in parallel execution environments
+        if ($modules->discoverInComposer && ! $this->composerNamespacesLoaded) {
             $composerPackages = $modules->composerPackages;
             $this->loadComposerNamespaces($composer, $composerPackages ?? []);
+            $this->composerNamespacesLoaded = true;
         }
 
         unset($composer);
@@ -371,6 +381,24 @@ public function sanitizeFilename(string $filename): string
         return $cleanFilename;
     }
 
+    /**
+     * Convert a path to absolute path if it isn't already.
+     * Prevents issues with relative paths in parallel execution.
+     */
+    private function makePathAbsolute(string $path): string
+    {
+        if (str_starts_with($path, '/') || (strlen($path) > 1 && $path[1] === ':')) {
+            return $path; // Already absolute
+        }
+
+        // Make relative to vendor directory
+        if (defined('VENDORPATH')) {
+            return VENDORPATH . ltrim($path, '/\\');
+        }
+
+        return $path;
+    }
+
     /**
      * @param array{only?: list<string>, exclude?: list<string>} $composerPackages
      */
@@ -441,7 +469,8 @@ private function loadComposerNamespaces(ClassLoader $composer, array $composerPa
 
             if ($add) {
                 // Composer stores namespaces with trailing slash. We don't.
-                $newPaths[rtrim($namespace, '\\ ')] = $srcPaths;
+                // Ensure all paths are absolute to prevent issues in parallel execution
+                $newPaths[rtrim($namespace, '\\ ')] = array_map($this->makePathAbsolute(...), $srcPaths);
             }
         }