bug #376 [make:validator] Custom constraints should ignore null and empty values (voronkovich)

This PR was squashed before being merged into the 1.0-dev branch (closes #376).

Discussion
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[make:validator] Custom constraints should ignore null and empty values

See https://symfony.com/doc/current/validation/custom_constraint.html#creating-the-validator-itself

Commits
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c959791 [make:validator] Custom constraints should ignore null and empty values

Author: weaverryan

src/Resources/skeleton/validator/Validator.tpl.php

@@ -11,6 +11,11 @@ public function validate($value, Constraint $constraint)
     {
         /* @var $constraint \<?= $constraint_class_name ?> */
 
+        if (null === $value || '' === $value) {
+            return;
+        }
+
+        // TODO: implement the validation here
         $this->context->buildViolation($constraint->message)
             ->setParameter('{{ value }}', $value)
             ->addViolation();