From 143e8d13445ee071602699c2a96d792a7051ec96 Mon Sep 17 00:00:00 2001
From: Sergei Morozov <morozov@tut.by>
Date: Wed, 21 Jul 2021 06:57:00 -0700
Subject: [PATCH] Do not call strlen() on null (#657)

---
 src/JsonSchema/Constraints/Constraint.php | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/JsonSchema/Constraints/Constraint.php b/src/JsonSchema/Constraints/Constraint.php
index a53130df..c61b89ad 100644
--- a/src/JsonSchema/Constraints/Constraint.php
+++ b/src/JsonSchema/Constraints/Constraint.php
@@ -42,10 +42,15 @@ abstract class Constraint extends BaseConstraint implements ConstraintInterface
     protected function incrementPath(JsonPointer $path = null, $i)
     {
         $path = $path ?: new JsonPointer('');
+
+        if ($i === null || $i === '') {
+            return $path;
+        }
+
         $path = $path->withPropertyPaths(
             array_merge(
                 $path->getPropertyPaths(),
-                array_filter(array($i), 'strlen')
+                array($i)
             )
         );