Only include non-element children alongside a matching element

Keep the property table of children() consistent with sxe_prop_is_empty():
an element whose only children are PIs or comments (or with no child in the
requested namespace) is still empty, so (bool) and (array) agree.

Author: Truta446

ext/simplexml/simplexml.c

@@ -1109,8 +1109,9 @@ static HashTable *sxe_get_prop_hash(zend_object *object, int is_debug) /* {{{ */
 	GET_NODE(sxe, node);
 	if (sxe->iter.type == SXE_ITER_CHILD) {
 		/* Start at the first child rather than at the first element child, so that
-		 * non-element nodes (e.g. PIs, comments) before it are not skipped. */
-		node = node ? node->children : NULL;
+		 * non-element nodes (e.g. PIs, comments) before it are not skipped. Like
+		 * sxe_prop_is_empty(), only do so if there is a matching element child. */
+		node = php_sxe_get_first_node_non_destructive(sxe, node) ? node->children : NULL;
 	} else {
 		node = php_sxe_get_first_node_non_destructive(sxe, node);
 	}

ext/simplexml/tests/gh12168.phpt

@@ -21,6 +21,22 @@ foreach ([
     echo $xml, ': ', json_encode(array_keys((array) $sxe->children())), "\n";
 }
 
+/* Non-element nodes only show up alongside a matching element, consistent with (bool) */
+foreach ([
+    '<c><?pi a?></c>',
+    '<c><!-- c --></c>',
+    '<c>t<?pi a?></c>',
+    '<!DOCTYPE c [<!ENTITY e "v">]><c>&e;<x/></c>',
+] as $xml) {
+    $sxe = simplexml_load_string($xml);
+    echo $xml, ': ', json_encode(array_keys((array) $sxe->children())), ' ', var_export((bool) $sxe->children(), true), "\n";
+}
+
+$sxe = simplexml_load_string('<c xmlns:a="urn:a"><?pi a?><y/><a:x/></c>');
+var_dump(array_keys((array) $sxe->children('urn:a')));
+$sxe = simplexml_load_string('<c xmlns:a="urn:a"><?pi a?><y/></c>');
+var_dump(array_keys((array) $sxe->children('urn:a')), (bool) $sxe->children('urn:a'));
+
 ?>
 --EXPECTF--
 object(SimpleXMLElement)#%d (2) {
@@ -43,3 +59,16 @@ object(SimpleXMLElement)#%d (2) {
 <c><x/><!-- c --></c>: ["x","comment"]
 <c><?pi a?><x/><?pi b?><y/></c>: ["pi","x","y"]
 <c>text</c>: []
+<c><?pi a?></c>: [] false
+<c><!-- c --></c>: [] false
+<c>t<?pi a?></c>: [] false
+<!DOCTYPE c [<!ENTITY e "v">]><c>&e;<x/></c>: ["e","x"] true
+array(2) {
+  [0]=>
+  string(2) "pi"
+  [1]=>
+  string(1) "x"
+}
+array(0) {
+}
+bool(false)