[1.x] fix: resolve translation references in implicitly-loaded fallback catalogues

framework/core/src/Locale/Translator.php

@@ -17,6 +17,17 @@ class Translator extends BaseTranslator implements TranslatorContract
 {
     const REFERENCE_REGEX = '/^=>\s*([a-z0-9_\-\.]+)$/i';
 
+    /**
+     * Catalogue objects whose `=> reference` values have already been resolved.
+     *
+     * Tracked per object rather than per locale: Symfony stores an original
+     * catalogue per locale but attaches fresh copies as fallbacks of other
+     * locales, so several objects can share one locale name.
+     *
+     * @var \SplObjectStorage|null
+     */
+    private $parsedCatalogues;
+
     public function get($key, array $replace = [], $locale = null)
     {
         return $this->trans($key, $replace, null, $locale);
@@ -39,16 +50,16 @@ public function getCatalogue($locale = null)
             $this->assertValidLocale($locale);
         }
 
-        $parse = ! isset($this->catalogues[$locale]);
-
         $catalogue = parent::getCatalogue($locale);
 
-        if ($parse) {
-            $this->parseCatalogue($catalogue);
+        if ($this->parsedCatalogues === null) {
+            $this->parsedCatalogues = new \SplObjectStorage();
+        }
 
-            $fallbackCatalogue = $catalogue;
-            while ($fallbackCatalogue = $fallbackCatalogue->getFallbackCatalogue()) {
-                $this->parseCatalogue($fallbackCatalogue);
+        for ($current = $catalogue; $current !== null; $current = $current->getFallbackCatalogue()) {
+            if (! $this->parsedCatalogues->contains($current)) {
+                $this->parseCatalogue($current);
+                $this->parsedCatalogues->attach($current);
             }
         }
 

framework/core/tests/unit/Locale/TranslatorReferenceResolutionTest.php

@@ -0,0 +1,84 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\unit\Locale;
+
+use Flarum\Locale\PrefixedYamlFileLoader;
+use Flarum\Locale\Translator;
+use Flarum\Testing\unit\TestCase;
+use Symfony\Component\Translation\MessageCatalogueInterface;
+
+class TranslatorReferenceResolutionTest extends TestCase
+{
+    private const DOMAIN = 'messages'.MessageCatalogueInterface::INTL_DOMAIN_SUFFIX;
+
+    /**
+     * @var string
+     */
+    private $cacheDir;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->cacheDir = sys_get_temp_dir().'/flarum-translator-test-'.uniqid('', true);
+        mkdir($this->cacheDir);
+
+        file_put_contents($this->cacheDir.'/en.yml', "foo: '=> bar'\nbar: Resolved\n");
+        file_put_contents($this->cacheDir.'/de.yml', "baz: Beispiel\n");
+    }
+
+    protected function tearDown(): void
+    {
+        array_map('unlink', glob($this->cacheDir.'/*') ?: []);
+        rmdir($this->cacheDir);
+
+        parent::tearDown();
+    }
+
+    private function translator(): Translator
+    {
+        // Wired like LocaleServiceProvider: non-debug, cache dir, 'en' fallback.
+        $translator = new Translator('de', null, $this->cacheDir, false);
+        $translator->setFallbackLocales(['en']);
+        $translator->addLoader('prefixed_yaml', new PrefixedYamlFileLoader());
+        $translator->addResource('prefixed_yaml', ['file' => $this->cacheDir.'/en.yml', 'prefix' => ''], 'en', self::DOMAIN);
+        $translator->addResource('prefixed_yaml', ['file' => $this->cacheDir.'/de.yml', 'prefix' => ''], 'de', self::DOMAIN);
+
+        return $translator;
+    }
+
+    public function test_references_are_resolved_when_locale_is_loaded_directly()
+    {
+        $translator = $this->translator();
+
+        $this->assertSame('Resolved', $translator->getCatalogue('en')->get('foo', 'messages'));
+    }
+
+    public function test_references_are_resolved_when_locale_was_first_loaded_as_a_fallback()
+    {
+        $translator = $this->translator();
+
+        // Loading 'de' makes Symfony implicitly load and store the 'en'
+        // catalogue as its fallback, before 'en' is ever requested directly.
+        $translator->getCatalogue('de');
+
+        $this->assertSame('Resolved', $translator->getCatalogue('en')->get('foo', 'messages'));
+    }
+
+    public function test_references_are_resolved_in_fallback_catalogues()
+    {
+        $translator = $this->translator();
+
+        $fallback = $translator->getCatalogue('de')->getFallbackCatalogue();
+
+        $this->assertSame('Resolved', $fallback->get('foo', 'messages'));
+        $this->assertSame('Resolved', $translator->trans('foo', [], null, 'de'));
+    }
+}