fix: replace null character when serializing

Signed-off-by: SebastianKrupinski <krupinskis05@gmail.com>

Author: SebastianKrupinski

apps/dav/lib/DAV/CustomPropertiesBackend.php

@@ -226,7 +226,7 @@ public function propFind($path, PropFind $propFind) {
 			} catch (DavException $e) {
 				continue;
 			}
-			$propFind->set($propName, $propValue);
+ 			$propFind->set($propName, $propValue);
 		}
 		foreach ($this->getUserProperties($path, $requestedProps) as $propName => $propValue) {
 			try {
@@ -519,7 +519,9 @@ private function encodeValueForDatabase(string $path, string $name, mixed $value
 			$value = $value->getHref();
 		} else {
 			$valueType = self::PROPERTY_TYPE_OBJECT;
-			$value = serialize($value);
+			// serialize produces null character
+			// these can not be properly stored in some databases and need to be replaced
+			$value = str_replace(chr(0), ' ', serialize($value));
 		}
 		return [$value, $valueType];
 	}