Fix split filter for php >=8.0 in case of empty separator

src/Liquid/StandardFilters.php

@@ -621,6 +621,14 @@ public static function split($input, $pattern)
  return [];
  }
 
+ if ($pattern === '') {
+ return mb_str_split($input);
+ }
+
+ if (empty($pattern)) {
+ return [$input];
+ }
+
  return explode($pattern, $input);
  }
 

tests/Liquid/StandardFiltersTest.php

@@ -881,6 +881,16 @@ public function testSplit()
  array('123', '123', '123'),
  '0'
  ),
+ array(
+ 'phrase',
+ array('p', 'h', 'r', 'a', 's', 'e'),
+ ''
+ ),
+ array(
+ 'phrase',
+ array('phrase'),
+ null
+ )
  );
 
  foreach ($data as $item) {