MFH: fix bug #43221 (SimpleXML adding default namespace in addAttribute)

add test

ext/simplexml/simplexml.c

@@ -1655,6 +1655,13 @@ SXE_METHOD(addAttribute)
 
 	localname = xmlSplitQName2((xmlChar *)qname, &prefix);
 	if (localname == NULL) {
+		if (nsuri_len > 0) {
+			if (prefix != NULL) {
+				xmlFree(prefix);
+			}
+			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Attribute requires prefix for namespace");
+			return;
+		}
 		localname = xmlStrdup((xmlChar *)qname);
 	}
 

ext/simplexml/tests/bug43221.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Bug #43221 (SimpleXML adding default namespace in addAttribute)
+--FILE--
+<?php
+$xml = simplexml_load_string('<?xml version="1.0" encoding="utf-8"?><root />');
+$n = $xml->addChild("node", "value");
+$n->addAttribute("a", "b");
+$n->addAttribute("c", "d", "http://bar.com");
+$n->addAttribute("foo:e", "f", "http://bar.com");
+print_r($xml->asXml());
+?>
+--EXPECTF--
+Warning: SimpleXMLElement::addAttribute(): Attribute requires prefix for namespace in %sbug43221.php on line %d
+<?xml version="1.0" encoding="utf-8"?>
+<root><node xmlns:foo="http://bar.com" a="b" foo:e="f">value</node></root>