Fix symfony/intl for newer PHP Versions

composer require sulu/symfony-intl-fix

To avoid problems you should also exclude the default Locale class from the classmap in your composer.json:

{
    "autoload": {
        "exclude-from-classmap": [
             "vendor/symfony/intl/Locale.php",
             "vendor/symfony/symfony/src/Symfony/Component/Intl/Locale.php"
        ]
    }
}

Affected PHP Versions:

• ^7.3.4
• ^7.2.17
• ^7.1.28

If you use one of the above PHP Version and an older Symfony Intl version than
^3.4.24 or ^4.2.7 symfony/intl will end up in an infinite loop.

This package will overwrite the Symfony Locale to avoid this infinite
loop. Projects using Symfony 3 or 4 should just update there symfony package.
This fix is mainly provided for Symfony 2 projects.

What was changed to fix the issue?

The change in Locale.php is really simple:

-            return locale_compose($localeSubTags);
+            $fallback = locale_compose($localeSubTags);
+
+            return false !== $fallback ? $fallback : null;

See original commit.