Comments are not SimpleXML element children

- Comments should not be counted as node children

Closes #863

hphp/runtime/ext/ext_simplexml.cpp

@@ -165,6 +165,8 @@ static Array create_children(CResRef doc, xmlNodePtr root,
                              CStrRef ns, bool is_prefix) {
   Array properties = Array::Create();
   for (xmlNodePtr node = root->children; node; node = node->next) {
+    if (root->parent && root->parent->type == XML_DOCUMENT_NODE &&
+        node->type == XML_COMMENT_NODE) continue;
     if (node->children || node->prev || node->next) {
       if (node->type == XML_TEXT_NODE) {
         // bad node from parser, ignoring it...

hphp/test/slow/simple_xml/exclude_comments.php

@@ -0,0 +1,14 @@
+<?php
+
+$element = simplexml_load_string(<<<EOF
+<root>
+  <!-- I am a comment -->
+  <elem1>
+    <elem2 />
+    <!-- I am also a comment -->
+  </elem1>
+</root>
+EOF
+);
+var_dump($element->count());
+var_dump($element->elem1->count());

hphp/test/slow/simple_xml/exclude_comments.php.expect

@@ -0,0 +1,2 @@
+int(1)
+int(1)