[BUGFIX] Check if site language is enabled before redirecting

Only if a site language is enabled, it should be taken into account for
redirecting.
To keep the interface valid, the 1st site language is returned if no
other site language is found.

Resolves: #93920
Releases: master, 10.4
Change-Id: I304c845012d3d76cd230e775030ac08a8d003e6b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68775
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/frontend/Classes/Middleware/SiteBaseRedirectResolver.php

@@ -58,7 +58,13 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
         if ($site instanceof Site && !($language instanceof SiteLanguage)) {
             if ($routeResult instanceof SiteRouteResult && $routeResult->getTail() === '') {
                 $language = $site->getDefaultLanguage();
-                return new RedirectResponse($language->getBase(), 307);
+                if ($language->isEnabled()) {
+                    return new RedirectResponse($language->getBase(), 307);
+                }
+                // Default language is disabled, check for the first (enabled) language in list to redirect to that
+                foreach ($site->getLanguages() as $language) {
+                    return new RedirectResponse($language->getBase(), 307);
+                }
             }
             return GeneralUtility::makeInstance(ErrorController::class)->pageNotFoundAction(
                 $request,

typo3/sysext/frontend/Tests/Unit/Middleware/SiteBaseRedirectResolverTest.php

@@ -301,4 +301,80 @@ public function doNotRedirectOnBaseWithoutQuery(
         $response = $subject->process($request, $this->siteFoundRequestHandler);
         self::assertEquals(200, $response->getStatusCode());
     }
+
+    /**
+     * @test
+     */
+    public function useDefaultLanguageIfNoLanguageIsGiven(): void
+    {
+        $incomingUrl = 'https://twenty.one/';
+        $site = new Site('random-site', 13, [
+            'base' => 'https://twenty.one/',
+            'languages' => [
+                0 => [
+                    'languageId' => 0,
+                    'locale' => 'en_US.UTF-8',
+                    'base' => '/en/'
+                ],
+                1 => [
+                    'languageId' => 1,
+                    'locale' => 'fr_FR.UTF-8',
+                    'base' => '/fr'
+                ],
+                2 => [
+                    'languageId' => 2,
+                    'locale' => 'fr_CA.UTF-8',
+                    'base' => '/fr_ca'
+                ]
+            ]
+        ]);
+
+        $routeResult = new SiteRouteResult(new Uri($incomingUrl), $site);
+        $request = new ServerRequest($incomingUrl, 'GET');
+        $request = $request->withAttribute('site', $site);
+        $request = $request->withAttribute('routing', $routeResult);
+
+        $subject = new SiteBaseRedirectResolver();
+        $response = $subject->process($request, $this->siteFoundRequestHandler);
+        self::assertEquals('https://twenty.one/en/', $response->getHeader('Location')[0]);
+    }
+
+    /**
+     * @test
+     */
+    public function useFirstAvailableLanguageIfDefaultLanguageIsNotEnabledAndLanguageIsGiven(): void
+    {
+        $incomingUrl = 'https://twenty.one/';
+        $site = new Site('random-site', 13, [
+            'base' => 'https://twenty.one/',
+            'languages' => [
+                0 => [
+                    'languageId' => 0,
+                    'enabled' => false,
+                    'locale' => 'en_US.UTF-8',
+                    'base' => '/en/'
+                ],
+                1 => [
+                    'languageId' => 1,
+                    'enabled' => false,
+                    'locale' => 'fr_FR.UTF-8',
+                    'base' => '/fr'
+                ],
+                2 => [
+                    'languageId' => 2,
+                    'locale' => 'fr_CA.UTF-8',
+                    'base' => '/fr_ca'
+                ]
+            ]
+        ]);
+
+        $routeResult = new SiteRouteResult(new Uri($incomingUrl), $site);
+        $request = new ServerRequest($incomingUrl, 'GET');
+        $request = $request->withAttribute('site', $site);
+        $request = $request->withAttribute('routing', $routeResult);
+
+        $subject = new SiteBaseRedirectResolver();
+        $response = $subject->process($request, $this->siteFoundRequestHandler);
+        self::assertEquals('https://twenty.one/fr_ca', $response->getHeader('Location')[0]);
+    }
 }