Fix passing null to abs() function at Nested::shiftRangeRL()

Author: tacman

CHANGELOG.md

@@ -21,6 +21,10 @@ a release.
 
 ### Fixed
 - Tree: Allow sorting children by a ManyToOne relation (#2492)
+- Tree: Fix passing `null` to `abs()` function
+
+### Deprecated
+- Tree: Passing `null` as argument 8 to `Nested::shiftRangeRL()`
 
 ## [3.8.0] - 2022-07-17
 ### Added

src/Tree/Strategy/ORM/Nested.php

@@ -639,6 +639,18 @@ public function shiftRL(EntityManagerInterface $em, $class, $first, $delta, $roo
      */
     public function shiftRangeRL(EntityManagerInterface $em, $class, $first, $last, $delta, $root = null, $destRoot = null, $levelDelta = null)
     {
+        // @todo: Remove the following condition and assignment in the next major release and use 0 as default value for
+        // the `$levelDelta` parameter.
+        if (null === $levelDelta && func_num_args() >= 8) {
+            @trigger_error(sprintf(
+                'Passing a type different than "int" as argument 8 to "%s()" is deprecated since gedmo/doctrine-extensions'.
+                ' 3.x and will throw a "%s" error in version 4.0.',
+                __METHOD__,
+                \TypeError::class
+            ), E_USER_DEPRECATED);
+        }
+        $levelDelta = $levelDelta ?? 0;
+
         $meta = $em->getClassMetadata($class);
         $config = $this->listener->getConfiguration($em, $class);