Removed isset() micro optimization. It is no longer valid php/php-src#3360

Author: germanow

src/ArrayHelper.php

@@ -180,7 +180,10 @@ public static function getValue($array, $key, $default = null)
             $key = $lastKey;
         }
 
-        if (is_array($array) && (isset($array[$key]) || array_key_exists($key, $array))) {
+        if (is_float($key)) {
+            $key = (int) $key;
+        }
+        if (is_array($array) && array_key_exists($key, $array)) {
             return $array[$key];
         }
 
@@ -196,7 +199,7 @@ public static function getValue($array, $key, $default = null)
         }
 
         if (is_array($array)) {
-            return (isset($array[$key]) || array_key_exists($key, $array)) ? $array[$key] : $default;
+            return array_key_exists($key, $array) ? $array[$key] : $default;
         }
 
         return $default;
@@ -298,7 +301,7 @@ public static function setValue(array &$array, $path, $value): void
      */
     public static function remove(array &$array, string $key, $default = null)
     {
-        if (isset($array[$key]) || array_key_exists($key, $array)) {
+        if (array_key_exists($key, $array)) {
             $value = $array[$key];
             unset($array[$key]);
 
@@ -583,9 +586,7 @@ public static function map(array $array, $from, $to, $group = null): array
     public static function keyExists(array $array, string $key, bool $caseSensitive = true): bool
     {
         if ($caseSensitive) {
-            // Function `isset` checks key faster but skips `null`, `array_key_exists` handles this case
-            // http://php.net/manual/en/function.array-key-exists.php#107786
-            return isset($array[$key]) || array_key_exists($key, $array);
+            return array_key_exists($key, $array);
         }
 
         foreach (array_keys($array) as $k) {