[Translation] Improve LocaleSwitcher a bit

Author: nicolas-grekas

LocaleSwitcher.php

@@ -11,23 +11,31 @@
 
 namespace Symfony\Component\Translation;
 
+use Symfony\Component\Routing\RequestContext;
 use Symfony\Contracts\Translation\LocaleAwareInterface;
 
 /**
  * @author Kevin Bond <[email protected]>
  */
-final class LocaleSwitcher implements LocaleAwareInterface
+class LocaleSwitcher implements LocaleAwareInterface
 {
+    private string $defaultLocale;
+
     /**
      * @param LocaleAwareInterface[] $localeAwareServices
      */
-    public function __construct(private string $locale, private iterable $localeAwareServices)
-    {
+    public function __construct(
+        private string $locale,
+        private iterable $localeAwareServices,
+        private ?RequestContext $requestContext = null,
+    ) {
+        $this->defaultLocale = $locale;
     }
 
     public function setLocale(string $locale): void
     {
         \Locale::setDefault($this->locale = $locale);
+        $this->requestContext?->setParameter('_locale', $locale);
 
         foreach ($this->localeAwareServices as $service) {
             $service->setLocale($locale);
@@ -42,17 +50,26 @@ public function getLocale(): string
     /**
      * Switch to a new locale, execute a callback, then switch back to the original.
      *
-     * @param callable():void $callback
+     * @template T
+     *
+     * @param callable():T $callback
+     *
+     * @return T
      */
-    public function runWithLocale(string $locale, callable $callback): void
+    public function runWithLocale(string $locale, callable $callback): mixed
     {
         $original = $this->getLocale();
         $this->setLocale($locale);
 
         try {
-            $callback();
+            return $callback();
         } finally {
             $this->setLocale($original);
         }
     }
+
+    public function reset(): void
+    {
+        $this->setLocale($this->defaultLocale);
+    }
 }

Tests/LocaleSwitcherTest.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Translation\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Routing\RequestContext;
 use Symfony\Component\Translation\LocaleSwitcher;
 use Symfony\Contracts\Translation\LocaleAwareInterface;
 
@@ -75,6 +76,24 @@ public function testCanSwitchLocaleForCallback()
         $this->assertSame('en', $service->getLocale());
         $this->assertSame('en', $switcher->getLocale());
     }
+
+    public function testWithRequestContext()
+    {
+        $context = new RequestContext();
+        $service = new LocaleSwitcher('en', [], $context);
+
+        $this->assertSame('en', $service->getLocale());
+
+        $service->setLocale('fr');
+
+        $this->assertSame('fr', $service->getLocale());
+        $this->assertSame('fr', $context->getParameter('_locale'));
+
+        $service->reset();
+
+        $this->assertSame('en', $service->getLocale());
+        $this->assertSame('en', $context->getParameter('_locale'));
+    }
 }
 
 class DummyLocaleAware implements LocaleAwareInterface

composer.json

@@ -28,6 +28,7 @@
         "symfony/http-kernel": "^5.4|^6.0",
         "symfony/intl": "^5.4|^6.0",
         "symfony/polyfill-intl-icu": "^1.21",
+        "symfony/routing": "^5.4|^6.0",
         "symfony/service-contracts": "^1.1.2|^2|^3",
         "symfony/yaml": "^5.4|^6.0",
         "symfony/finder": "^5.4|^6.0",