Fixed bug #79852

NEWS

@@ -11,6 +11,8 @@ PHP                                                                        NEWS
     (Nikita)
   . Fixed bug #79828 (Segfault when trying to access non-existing variable).
     (Nikita)
+  . Fixed bug #79852 (count(DOMNodeList) doesn't match
+    count(IteratorIterator(DOMNodeList))). (Nikita)
 
 09 Jul 2020, PHP 8.0.0alpha2
 

Zend/zend_interfaces.c

@@ -469,6 +469,7 @@ ZEND_API int zend_create_internal_iterator_zval(zval *return_value, zval *obj) {
 	zend_internal_iterator *intern =
 		(zend_internal_iterator *) zend_internal_iterator_create(zend_ce_internal_iterator);
 	intern->iter = iter;
+	intern->iter->index = 0;
 	ZVAL_OBJ(return_value, &intern->std);
 	return SUCCESS;
 }
@@ -559,8 +560,9 @@ ZEND_METHOD(InternalIterator, next) {
 		RETURN_THROWS();
 	}
 
-	intern->iter->funcs->move_forward(intern->iter);
+	/* Advance index first to match foreach behavior. */
 	intern->iter->index++;
+	intern->iter->funcs->move_forward(intern->iter);
 }
 
 ZEND_METHOD(InternalIterator, valid) {

ext/dom/tests/bug79852.phpt

@@ -0,0 +1,36 @@
+--TEST--
+Bug #79852: count(DOMNodeList) doesn't match count(IteratorIterator(DOMNodeList))
+--FILE--
+<?php
+
+$XML = <<< XML
+<root>
+  <item>1</item>
+  <item>2</item>
+  <item>3</item>
+</root>
+XML;
+
+$dom = new DomDocument();
+$dom->loadXml($XML);
+$items = $dom->getElementsByTagName('item');
+
+echo "Count: ".count($items)."\n";
+echo "Count: ".iterator_count($items->getIterator())."\n";
+$it = new IteratorIterator($items);
+echo "Count: ".iterator_count($it)."\n";
+echo "Count: ".iterator_count($it)."\n";
+
+?>
+--EXPECTF--
+Count: 3
+Count: 3
+Count: 3
+
+Fatal error: Uncaught Error: Iterator does not support rewinding in %s:%d
+Stack trace:
+#0 [internal function]: InternalIterator->rewind()
+#1 [internal function]: IteratorIterator->rewind()
+#2 %s(%d): iterator_count(Object(IteratorIterator))
+#3 {main}
+  thrown in %s on line %d