fix: resolve %kernel.default_locale% parameter reference before validation

processConfiguration() does not resolve Symfony %param% references, so
the default_locale validation always failed when left at its default.
Resolve via ParameterBag::resolveValue() and store the resolved value
into container parameters. When the resolved value contains environment
variable placeholders (%env(...)%), skip compile-time validation since
the actual value is only known at runtime.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: CreativeNative

src/DependencyInjection/TmiTranslationExtension.php

@@ -50,13 +50,21 @@ public function load(array $configs, ContainerBuilder $container): void
 
         // Resolve default_locale — processConfiguration() does not resolve %param% references
         /** @var string $defaultLocale */
-        $defaultLocale            = $container->getParameterBag()->resolveValue($config['default_locale']);
-        $config['default_locale'] = $defaultLocale;
+        $defaultLocale = $container->getParameterBag()->resolveValue($config['default_locale']);
 
-        // Validate that default_locale is included in enabled_locales
-        if (!\in_array($defaultLocale, $enabledLocales, true)) {
-            throw new \LogicException(\sprintf('The default_locale "%s" must be included in framework.enabled_locales [%s].', $defaultLocale, implode(', ', $enabledLocales)));
+        // Detect whether the resolved value contains environment variable placeholders
+        $usedEnvs = [];
+        $container->resolveEnvPlaceholders($defaultLocale, null, $usedEnvs);
+
+        if ([] === $usedEnvs) {
+            // Static value — validate and store resolved locale
+            $config['default_locale'] = $defaultLocale;
+
+            if (!\in_array($defaultLocale, $enabledLocales, true)) {
+                throw new \LogicException(\sprintf('The default_locale "%s" must be included in framework.enabled_locales [%s].', $defaultLocale, implode(', ', $enabledLocales)));
+            }
         }
+        // When env vars are used, skip validation — the actual value is resolved at runtime
 
         // Set configuration into params
         $rootName = 'tmi_translation';

tests/DependencyInjection/TmiTranslationExtensionTest.php

@@ -335,6 +335,25 @@ public function testDefaultLocaleParameterReferenceIsResolved(): void
         self::assertSame('en_US', $containerBuilder->getParameter('tmi_translation.default_locale'));
     }
 
+    /**
+     * @throws Exception
+     * @throws TypesException
+     */
+    public function testDefaultLocaleEnvVarSkipsValidation(): void
+    {
+        $containerBuilder = new ContainerBuilder();
+        $containerBuilder->setParameter('kernel.enabled_locales', ['en_US', 'de_DE', 'it_IT']);
+        $containerBuilder->setParameter('kernel.default_locale', '%env(DEFAULT_LOCALE)%');
+
+        $extension = new TmiTranslationExtension();
+
+        // Should not throw — env vars cannot be validated at compile time
+        $extension->load([[]], $containerBuilder);
+
+        // The raw parameter reference is kept so Symfony resolves it at runtime
+        self::assertSame('%kernel.default_locale%', $containerBuilder->getParameter('tmi_translation.default_locale'));
+    }
+
     private function createContainerBuilderFromKernel(): ContainerBuilder
     {
         $containerBuilder = new ContainerBuilder();