[BUGFIX] Create unique marker names when adding new fields

This fixes a regression when field properties were extended with types and when the array should be changed to a field object.

Related: #787

Classes/Domain/Model/Field.php

@@ -141,9 +141,10 @@ class Field extends AbstractEntity
     protected int $l10nParent = 0;
 
     /**
-     * @var ?Page
+     * @var Page
+     * This property can hold Page|int|null (depending on the context). "@var" must set to Page for property mapping.
      */
-    protected ?Page $page = null;
+    protected $page = null;
 
     /**
      * @return string

Classes/Hook/CreateMarker.php

@@ -11,7 +11,6 @@
 use TYPO3\CMS\Backend\Utility\BackendUtility as BackendUtilityCore;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Extbase\Object\Exception;
-use TYPO3\CMS\Extbase\Persistence\Generic\Mapper\DataMapper;
 
 /**
  * Class CreateMarker to autofill field marker with value from title e.g. {firstname}
@@ -238,13 +237,16 @@ protected function addNewFields(): void
      */
     protected function getFieldObjectFromProperties(array $properties, string $uid = '0'): Field
     {
-        $dataMapper = GeneralUtility::makeInstance(DataMapper::class);
-        if (isset($properties['uid']) === false) {
-            $properties['uid'] = null;
+        $field = GeneralUtility::makeInstance(Field::class);
+        $properties['sender_email'] = (bool)$properties['sender_email'];
+        $properties['sender_name'] = (bool)$properties['sender_name'];
+        $properties['mandatory'] = (bool)$properties['mandatory'];
+        $properties['validation'] = (int)$properties['validation'];
+        foreach ($properties as $key => $value) {
+            $field->_setProperty(GeneralUtility::underscoredToLowerCamelCase($key), $value);
         }
-        $field = $dataMapper->map(Field::class, [$properties])[0];
         if (!empty($properties['sys_language_uid'])) {
-            $field->_setProperty('_languageUid', (int)$properties['sys_language_uid']);
+            $field->_setProperty('_languageUid', $properties['sys_language_uid']);
         }
         $field->setDescription((string)($properties['uid'] ?? '') > 0 ? (string)$properties['uid'] : $uid);
         return $field;