Fix #23326: Attributes via append_child not supported

Add testcase

ext/domxml/php_domxml.c

@@ -2425,11 +2425,6 @@ PHP_FUNCTION(domxml_node_append_child)
 	
 	DOMXML_GET_OBJ(child, node, le_domxmlnodep);
 
-	if (child->type == XML_ATTRIBUTE_NODE) {
-		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Can't append attribute node");
-		RETURN_FALSE;
-	}
-
 	/* XXX:ls */
 	if (child == parent) {
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Can't append node to itself");
@@ -2469,6 +2464,28 @@ PHP_FUNCTION(domxml_node_append_child)
 		}
 	}
 	/* end libxml2 code */
+	else if (child->type == XML_ATTRIBUTE_NODE) {
+		if (parent->properties != NULL) {
+			/* Check if an attribute with the same name exists */
+			xmlAttrPtr foundattrp;
+			if (child->ns == NULL)
+				foundattrp = xmlHasProp(parent, child->name);
+			else
+				foundattrp = xmlHasNsProp(parent, child->name, child->ns->href);
+			if ((foundattrp != NULL) && (foundattrp != (xmlAttrPtr) child)) {
+				xmlUnlinkNode((xmlNodePtr) foundattrp);
+				(void)xmlCopyProp(parent, (xmlAttrPtr) child);
+				/* We're in the dark here, what happened to the parent, let's
+				 * assume it's handled properly and return the new(?) parent
+				 */
+				new_child = parent;
+			}
+		}
+		/* For all other intents and purposes fall through to the xmlAddChild
+		 * call
+		 */
+	}
+
 	
 	if (NULL == new_child) {
 		new_child = xmlAddChild(parent, child);

ext/domxml/tests/bug23326.phpt

@@ -0,0 +1,21 @@
+--TEST--
+Attributes via append_child not supported (bug #23326)
+--SKIPIF--
+<?php require_once('skipif.inc'); ?>
+--FILE--
+<?php
+$document = domxml_new_doc('1.0');
+$test = $document->create_element('test');
+$j = 0;
+for($i=0;$i<10;$i++)
+{
+	if( $j < 5 )
+		$j = $i;
+	$test->append_child($document->create_attribute("key$j", $i));
+}
+$document->append_child($test);
+echo $document->dump_mem(1);
+?>
+--EXPECT--
+<?xml version="1.0"?>
+<test key0="0" key1="1" key2="2" key3="3" key4="4" key5="9"/>