Coerce numeric string keys from iterators when argument unpacking

Fixes GH-18581
Closes GH-19151

Author: iluuu1994

NEWS

@@ -5,6 +5,8 @@ PHP                                                                        NEWS
 - Core:
   . Fixed GH-19169 build issue with C++17 and ZEND_STATIC_ASSERT macro.
     (psumbera)
+  . Fixed bug GH-18581 (Coerce numeric string keys from iterators when argument
+    unpacking). (ilutov)
 
 - Hash:
   . Fix crash on clone failure. (nielsdos)

Zend/tests/gh18581.phpt

@@ -0,0 +1,32 @@
+--TEST--
+GH-18581: Coerce numeric string keys from iterators when argument unpacking
+--FILE--
+<?php
+
+function g() {
+    yield '100' => 'first';
+    yield '101' => 'second';
+    yield '102' => 'third';
+    yield 'named' => 'fourth';
+}
+
+function test($x = null, $y = null, ...$z) {
+    var_dump($x, $y, $z);
+    var_dump($z[0]);
+    var_dump($z['named']);
+}
+
+test(...g());
+
+?>
+--EXPECT--
+string(5) "first"
+string(6) "second"
+array(2) {
+  [0]=>
+  string(5) "third"
+  ["named"]=>
+  string(6) "fourth"
+}
+string(5) "third"
+string(6) "fourth"

Zend/zend_vm_def.h

@@ -5236,6 +5236,11 @@ ZEND_VM_C_LABEL(send_again):
 						}
 
 						name = Z_STR_P(&key);
+
+						zend_ulong tmp;
+						if (ZEND_HANDLE_NUMERIC(name, tmp)) {
+							name = NULL;
+						}
 					}
 				}