bug #20830 [FrameworkBundle] Fix validation cache warmer with failing or missing classes (nicolas-grekas)

This PR was merged into the 3.2 branch.

Discussion
----------

[FrameworkBundle] Fix validation cache warmer with failing or missing classes

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20739
| License       | MIT
| Doc PR        | -

Commits
-------

53234e9 [FrameworkBundle] Fix validation cache warmer with failing or missing classes

src/Symfony/Bundle/FrameworkBundle/CacheWarmer/ValidatorCacheWarmer.php

@@ -66,12 +66,23 @@ class ValidatorCacheWarmer implements CacheWarmerInterface
         $loaders = $this->validatorBuilder->getLoaders();
         $metadataFactory = new LazyLoadingMetadataFactory(new LoaderChain($loaders), new Psr6Cache($arrayPool));
 
-        foreach ($this->extractSupportedLoaders($loaders) as $loader) {
-            foreach ($loader->getMappedClasses() as $mappedClass) {
-                if ($metadataFactory->hasMetadataFor($mappedClass)) {
-                    $metadataFactory->getMetadataFor($mappedClass);
+        $throwingAutoloader = function ($class) { throw new \ReflectionException(sprintf('Class %s does not exist', $class)); };
+        spl_autoload_register($throwingAutoloader);
+
+        try {
+            foreach ($this->extractSupportedLoaders($loaders) as $loader) {
+                foreach ($loader->getMappedClasses() as $mappedClass) {
+                    try {
+                        if ($metadataFactory->hasMetadataFor($mappedClass)) {
+                            $metadataFactory->getMetadataFor($mappedClass);
+                        }
+                    } catch (\ReflectionException $e) {
+                        // ignore failing reflection
+                    }
                 }
             }
+        } finally {
+            spl_autoload_unregister($throwingAutoloader);
         }
 
         $values = $arrayPool->getValues();

src/Symfony/Bundle/FrameworkBundle/Tests/Fixtures/Validation/Article.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Symfony\Bundle\FrameworkBundle\Tests\Fixtures\Validation;
+
+class Article implements NotExistingInterface
+{
+    public $category;
+}

src/Symfony/Bundle/FrameworkBundle/Tests/Fixtures/Validation/Resources/person.xml

@@ -16,8 +16,8 @@
         </property>
     </class>
 
-    <class name="Symfony\Bundle\FrameworkBundle\Tests\Fixtures\Validation\NonExistentClass">
-        <property name="gender">
+    <class name="Symfony\Bundle\FrameworkBundle\Tests\Fixtures\Validation\Article">
+        <property name="category">
             <constraint name="Choice">
                 <option name="choices">
                     <value>other</value>