do not enable validator auto mapping by default

Author: xabbuh

DependencyInjection/AddAutoMappingConfigurationPass.php

@@ -70,8 +70,12 @@ public function process(ContainerBuilder $container)
     /**
      * Builds a regexp to check if a class is auto-mapped.
      */
-    private function getRegexp(array $patterns): string
+    private function getRegexp(array $patterns): ?string
     {
+        if (!$patterns) {
+            return null;
+        }
+
         $regexps = [];
         foreach ($patterns as $pattern) {
             // Escape namespace

Tests/DependencyInjection/AddAutoMappingConfigurationPassTest.php

@@ -70,4 +70,17 @@ public function mappingProvider(): array
             ['Symfony\Component\Validator\Tests\Fixtures\\**', ['trailing_double_star'], '{^App\\\\|^Symfony\\\\Component\\\\Validator\\\\Tests\\\\Fixtures\\\\.*?$}'],
         ];
     }
+
+    public function testDoNotMapAllClassesWhenConfigIsEmpty()
+    {
+        $container = new ContainerBuilder();
+        $container->setParameter('validator.auto_mapping', []);
+
+        $container->register('validator.builder', ValidatorBuilder::class);
+        $container->register('loader')->addTag('validator.auto_mapper');
+
+        (new AddAutoMappingConfigurationPass())->process($container);
+
+        $this->assertNull($container->getDefinition('loader')->getArgument('$classValidatorRegexp'));
+    }
 }