fix: set_radio() implementation

Author: kenjis

system/Helpers/form_helper.php

@@ -650,14 +650,21 @@ function set_radio(string $field, string $value = '', bool $default = false): st
         $request = Services::request();
 
         // Try any old input data we may have first
-        $input = $request->getOldInput($field);
-        if ($input === null) {
-            $input = $request->getPost($field) ?? $default;
+        $oldInput = $request->getOldInput($field);
+
+        $postInput = $request->getPost($field);
+
+        if ($oldInput !== null) {
+            $input = $oldInput;
+        } elseif ($postInput !== null) {
+            $input = $postInput;
+        } else {
+            $input = $default;
         }
 
         if (is_array($input)) {
             // Note: in_array('', array(0)) returns TRUE, do not use it
-            foreach ($input as &$v) {
+            foreach ($input as $v) {
                 if ($value === $v) {
                     return ' checked="checked"';
                 }
@@ -667,16 +674,11 @@ function set_radio(string $field, string $value = '', bool $default = false): st
         }
 
         // Unchecked checkbox and radio inputs are not even submitted by browsers ...
-        $result = '';
-        if ((string) $input === '0' || ! empty($input = $request->getPost($field)) || ! empty($input = old($field))) {
-            $result = ($input === $value) ? ' checked="checked"' : '';
-        }
-
-        if (empty($result)) {
-            $result = ($default === true) ? ' checked="checked"' : '';
+        if ($oldInput !== null || $postInput !== null) {
+            return ((string) $input === $value) ? ' checked="checked"' : '';
         }
 
-        return $result;
+        return ($default === true) ? ' checked="checked"' : '';
     }
 }