[SimpleXML] Fix namespace filter on element returned by addChild()

NEWS

@@ -41,6 +41,10 @@ PHP                                                                        NEWS
   . Fixed a leak when a persistent connection failed a liveness check
     with no other live PDO handle. (iliaal)
 
+- SimpleXML:
+  . Fixed child elements of the element returned by SimpleXMLElement::addChild()
+    not being accessible by property name when namespaces are involved. (iliaal)
+
 - Standard:
   . Fixed a memory leak in array_merge_recursive() when the recursive merge of
     an object converted to an array fails. (David Carlier)

ext/simplexml/simplexml.c

@@ -1728,7 +1728,8 @@ PHP_METHOD(SimpleXMLElement, addChild)
 		}
 	}
 
-	node_as_zval_str(sxe, newnode, return_value, SXE_ITER_NONE, localname, prefix, 0);
+	node_as_zval_str(sxe, newnode, return_value, SXE_ITER_NONE, localname,
+		newnode->ns ? newnode->ns->prefix : NULL, 1);
 
 	xmlFree(localname);
 	if (prefix != NULL) {

ext/simplexml/tests/addChild_ns_filter_returned_element.phpt

@@ -0,0 +1,26 @@
+--TEST--
+SimpleXML::addChild() wrong namespace filter on returned element
+--EXTENSIONS--
+simplexml
+--FILE--
+<?php
+$x = new SimpleXMLElement('<r xmlns:a="http://example.com"/>');
+$c = $x->addChild('a:kid', null, 'http://example.com');
+$c->addChild('inner', 'v');
+echo trim($x->asXML()), "\n";
+echo (string) $c->inner, "\n";
+var_dump(isset($c->inner));
+$y = new SimpleXMLElement('<r xmlns:a="http://example.com"/>');
+$d = $y->addChild('kid', null, 'http://example.com');
+$d->addChild('inner', 'w');
+echo trim($y->asXML()), "\n";
+echo (string) $d->inner, "\n";
+?>
+--EXPECT--
+<?xml version="1.0"?>
+<r xmlns:a="http://example.com"><a:kid><a:inner>v</a:inner></a:kid></r>
+v
+bool(true)
+<?xml version="1.0"?>
+<r xmlns:a="http://example.com"><a:kid><a:inner>w</a:inner></a:kid></r>
+w