bug #31108 [FrameworkBundle] decorate the ValidatorBuilder's translator with LegacyTranslatorProxy (nicolas-grekas)

This PR was merged into the 4.2 branch.

Discussion
----------

[FrameworkBundle] decorate the ValidatorBuilder's translator with LegacyTranslatorProxy

| Q             | A
| ------------- | ---
| Branch?       | 4.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #31092, #31025
| License       | MIT
| Doc PR        | -

This allows defining a translator that implements only the new interface and use it with ValidatorBuilder.

ping @dvdknaap, @snebes since you were affected.

Commits
-------

a12656eaad [FrameworkBundle] decorate the ValidatorBuilder's translator with LegacyTranslatorProxy

Author: nicolas-grekas

ValidatorBuilder.php

@@ -258,7 +258,11 @@ public function setConstraintValidatorFactory(ConstraintValidatorFactoryInterfac
      */
     public function setTranslator(LegacyTranslatorInterface $translator)
     {
-        $this->translator = $translator instanceof LegacyTranslatorProxy ? $translator->getTranslator() : $translator;
+        $this->translator = $translator;
+
+        while ($this->translator instanceof LegacyTranslatorProxy) {
+            $this->translator = $this->translator->getTranslator();
+        }
 
         return $this;
     }