TYPO3 Core

It appears that something changes in the symfony router that causes endless redirect loop with TYPO3 routing.

Using symfony/routing, v4.2.4:

$ curl -I http://test.localhost.ops.ch/de/
HTTP/1.1 200 OK
Server: nginx/1.14.0
Date: Fri, 19 Apr 2019 10:00:00 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 113072
Connection: keep-alive
Vary: Accept-Encoding
Set-Cookie: fe_typo_user=20588581a60dd933465b18fe21b7fd02; path=/; HttpOnly
Content-Language: de

Updating only symfony/routing to v4.2.7:

$ curl -I http://test.localhost.ops.ch/de/
HTTP/1.1 307 Temporary Redirect
Server: nginx/1.14.0
Date: Fri, 19 Apr 2019 09:47:55 GMT
Content-Type: text/html; charset=UTF-8
Connection: keep-alive
location: //test.localhost.ops.ch/de/

Redirect comes from TYPO3\CMS\Core\Http\RedirectResponse (thanks to unique lowercase 'location'). Btw, it would be nice here to have some identifier in http headers, similar to what realurl did to identify the exact place that causes redirects (see, for example, https://github.com/dmitryd/typo3-realurl/blob/development/Classes/Decoder/UrlDecoder.php#L214 for such header).

I could trace the redirect to SiteBasedRedirectResolver::process():

        if ($site instanceof Site && !($language instanceof SiteLanguage)) {
            $language = $site->getDefaultLanguage();
            return new RedirectResponse($language->getBase(), 307);
        }

It seems that language is not detected due to this change in symfony router: https://github.com/symfony/routing/commit/0e5719d216017b1a0342fa48e86467cedca1c954

In UrlMatcher::matchCollection():

            $pos = strrpos($regex, '$');
            $hasTrailingSlash = '/' === $regex[$pos - 1];
            $regex = substr_replace($regex, '/?$', $pos - $hasTrailingSlash, 1 + $hasTrailingSlash);

            if (!preg_match($regex, $pathinfo, $matches)) {
                continue;
            }

            $hasTrailingVar = $trimmedPathinfo !== $pathinfo && preg_match('#\{\w+\}/?$#', $route->getPath());

            if ($hasTrailingVar && ($hasTrailingSlash || '/' !== substr($matches[(\count($matches) - 1) >> 1], -1)) && preg_match($regex, $trimmedPathinfo, $m)) {
                if ($hasTrailingSlash) {
                    $matches = $m;
                } else {
                    $hasTrailingVar = false;
                }
            }

Even though there is a trailing slash, regexp looks like #^/de(?:/(?P<tail>.*))?$#sDu. Later $hasTrailingVar becomes false and everything after the site name is ignored. Therefore TYPO3 tries to redirect to /de/ again.

My site configuration is quite ordinary:

rootPageId: 1
base: 'https://www.test.ch/'
baseVariants:
  -
    base: test.localhost.ops.ch
    condition: 'getenv("SITE_ENV") == "DEV"'
  -
    base: test.test00.snowflakehosting.ch
    condition: 'getenv("SITE_ENV") == "STAGE"'
languages:
  -
    title: Deutsch
    enabled: true
    languageId: '0'
    base: /de/
    typo3Language: de
    locale: de_CH.UTF-8
    iso-639-1: de
    navigationTitle: ''
    hreflang: ''
    direction: ''
    flag: de
  -
    title: English
    enabled: true
    languageId: '1'
    base: /en/
    typo3Language: default
    locale: en_US.UTF-8
    iso-639-1: en
    navigationTitle: ''
    hreflang: ''
    direction: ''
    fallbackType: strict
    fallbacks: '0'
    flag: gb
  -
    title: Français
    enabled: true
    languageId: '2'
    base: /fr/
    typo3Language: fr
    locale: fr_CH.UTF-8
    iso-639-1: fr
    navigationTitle: ''
    hreflang: ''
    direction: ''
    fallbackType: strict
    fallbacks: '0'
    flag: fr
  -
    title: Italiano
    enabled: true
    languageId: '3'
    base: /it/
    typo3Language: it
    locale: it_CH.UTF-8
    iso-639-1: it
    navigationTitle: ''
    hreflang: ''
    direction: ''
    fallbackType: strict
    fallbacks: '0'
    flag: it