Fix "lang.Error ([] operator not supported for strings)"

Author: thekid

ChangeLog.md

@@ -3,6 +3,9 @@ Web change log
 
 ## ?.?.? / ????-??-??
 
+* Fixed error *[] operator not supported for strings* when handling array
+  parameters
+  (@thekid)
 * Fixed multipart/formdata field names and values decoding, these are not
   urlencoded. Ignore the specification which states `"`, `\r` and `\n`
   need to be escaped for consistency with PHP, see php/php-src#8206

src/main/php/web/io/Param.class.php

@@ -75,6 +75,8 @@ public function merge(&$ptr) {
         $p= strcspn($this->array, ']', $o);
         $token= substr($this->array, $o + 1, $p - 1);
 
+        is_array($ptr) || $ptr= [];
+
         if ('' === $token) {
           $ptr= &$ptr[];
         } else {

src/test/php/web/unittest/ParamsTest.class.php

@@ -72,6 +72,10 @@ private function merge() {
       ['access[0][]', 'calendar'],
       ['access[1][]', 'wiki'],
     ]];
+    yield [[
+      ['key', 'value'],
+      ['key[]', 'test'],
+    ]];
   }
 
   #[Test, Values(from: 'params')]