[BUGFIX] Fix type cast error in DB Compare for 'default' definition

The change in #97498 introduced a specific handling for ENUM/SET
definitions in MariaDB systems. The check may be performed with a
NULL value instead of a string, which can result in a PHP type
mismatch error.

Due to other refactoring, the issue does not exist in main (v13),
but only affects v12 and v11.

Resolves: #104621
Related: #97498
Releases: 12.4, 11.5
Change-Id: Ia28aae519b1aebcabe9a5f5c620124dfd22edc6a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/85628


Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>

typo3/sysext/core/Classes/Database/Schema/EventListener/SchemaColumnDefinitionListener.php

@@ -66,7 +66,7 @@ class SchemaColumnDefinitionListener
         // Doctrine DBAL retrieves for MariaDB `ENUM()` and `SET()` field default values quotes with single quotes,
         // which leads to an endless field change reporting recursion in the database analyzer. The default value
         // is now trimmed to ensure a working field compare within `TYPO3\CMS\Core\Database\Schema\Comparator`.
-        if ($platform instanceof MariaDBPlatform && str_starts_with($default, "'") && str_ends_with($default, "'")) {
+        if (is_string($default) && $platform instanceof MariaDBPlatform && str_starts_with($default, "'") && str_ends_with($default, "'")) {
             $default = trim($default, "'");
         }
         $options = [