allow sorm to use other variants of I18NString, fixes #4891

Closes #4891

Merge request studip/studip!3664

lib/classes/SimpleORMap.php

@@ -84,6 +84,11 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
      */
     protected static $performs_batch_operation = false;
 
+    /**
+     * Defines which variant of the I18NString class should be used
+     */
+    protected string $i18n_class = I18NString::class;
+
     /**
      * name of db table
      * @return string
@@ -2232,7 +2237,10 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
         $field = strtolower($field);
         if ($this->content[$field] === null || $this->content_db[$field] === null) {
             return $this->content[$field] !== $this->content_db[$field];
-        } else if ($this->content[$field] instanceof I18NString || $this->content_db[$field] instanceof I18NString) {
+        } else if (
+            $this->content[$field] instanceof I18NString
+            || $this->content_db[$field] instanceof I18NString
+        ) {
             // Trigger loading of translations
             if ($this->content[$field] instanceof I18NString) {
                 $this->content[$field]->toArray();
@@ -2512,7 +2520,7 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
             $value->setMetadata($meta);
             $this->content[$field] = $value;
         } else {
-            $this->content[$field] = new I18NString($value, null, $meta);
+            $this->content[$field] = new $this->i18n_class($value, null, $meta);
         }
         return $this->content[$field];
     }

lib/models/DatafieldEntryModelI18N.php

@@ -28,6 +28,8 @@
 
 class DatafieldEntryModelI18N extends DatafieldEntryModel
 {
+    protected string $i18n_class = I18NStringDatafield::class;
+
     protected static function configure($config = [])
     {
         $config['i18n_fields']['content'] = true;