Merge pull request #1724 from mcorteel/v2.4.x

Use mb_strlen to get string length to avoid unicode characters problems

Author: l3pp4rd

lib/Gedmo/Sluggable/Mapping/Event/Adapter/ORM.php

@@ -82,7 +82,7 @@ public function replaceRelative($object, array $config, $target, $replacement)
         $qb->update($config['useObjectClass'], 'rec')
             ->set('rec.'.$config['slug'], $qb->expr()->concat(
                 $qb->expr()->literal($replacement),
-                $qb->expr()->substring('rec.'.$config['slug'], strlen($target))
+                $qb->expr()->substring('rec.'.$config['slug'], mb_strlen($target))
             ))
             ->where($qb->expr()->like(
                 'rec.'.$config['slug'],
@@ -105,7 +105,7 @@ public function replaceInverseRelative($object, array $config, $target, $replace
         $qb->update($config['useObjectClass'], 'rec')
             ->set('rec.'.$config['slug'], $qb->expr()->concat(
                 $qb->expr()->literal($target),
-                $qb->expr()->substring('rec.'.$config['slug'], strlen($replacement)+1)
+                $qb->expr()->substring('rec.'.$config['slug'], mb_strlen($replacement)+1)
             ))
             ->where($qb->expr()->like('rec.'.$config['slug'], $qb->expr()->literal($replacement . '%')))
         ;