minor #44742 [Validator] check for file existence lazily in loaders (…

…nicolas-grekas)

This PR was merged into the 6.1 branch.

Discussion
----------

[Validator] check for file existence lazily in loaders

| Q             | A
| ------------- | ---
| Branch?       | 6.1
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #39945
| License       | MIT
| Doc PR        | -

Commits
-------

9135405 [Validator] check for file existence lazily in loaders

src/Symfony/Component/Validator/Mapping/Loader/XmlFileLoader.php

@@ -30,6 +30,11 @@ class XmlFileLoader extends FileLoader
      */
     protected $classes;
 
+    public function __construct(string $file)
+    {
+        $this->file = $file;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -179,6 +184,8 @@ protected function parseFile(string $path): \SimpleXMLElement
 
     private function loadClassesFromXml()
     {
+        parent::__construct($this->file);
+
         // This method may throw an exception. Do not modify the class'
         // state before it completes
         $xml = $this->parseFile($this->file);

src/Symfony/Component/Validator/Mapping/Loader/YamlFileLoader.php

@@ -31,6 +31,11 @@ class YamlFileLoader extends FileLoader
      */
     protected $classes = null;
 
+    public function __construct(string $file)
+    {
+        $this->file = $file;
+    }
+
     /**
      * Caches the used YAML parser.
      */
@@ -131,6 +136,8 @@ private function parseFile(string $path): array
 
     private function loadClassesFromYaml()
     {
+        parent::__construct($this->file);
+
         $this->yamlParser ??= new YamlParser();
         $this->classes = $this->parseFile($this->file);