From 4fc27178e4a63a74f0dc6002509e01a93975a437 Mon Sep 17 00:00:00 2001
From: xml <xiamengliang@kingdom-tech.net>
Date: Thu, 9 Jan 2020 17:33:21 +0800
Subject: [PATCH] fix bug: if do c.SetNextSibling(nil) and c = c.NextSibling().
 After remove the first child the var c is always nil.the next child will not
 be set nil

---
 ast/ast.go      |  4 +++-
 ast/ast_test.go | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 ast/ast_test.go

diff --git a/ast/ast.go b/ast/ast.go
index 4f1d885..3ba6447 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -236,10 +236,12 @@ func (n *BaseNode) RemoveChild(self, v Node) {
 
 // RemoveChildren implements Node.RemoveChildren .
 func (n *BaseNode) RemoveChildren(self Node) {
-	for c := n.firstChild; c != nil; c = c.NextSibling() {
+	for c := n.firstChild; c != nil; {
 		c.SetParent(nil)
 		c.SetPreviousSibling(nil)
+		next := c.NextSibling()
 		c.SetNextSibling(nil)
+		c = next
 	}
 	n.firstChild = nil
 	n.lastChild = nil
diff --git a/ast/ast_test.go b/ast/ast_test.go
new file mode 100644
index 0000000..77a80f6
--- /dev/null
+++ b/ast/ast_test.go
@@ -0,0 +1,18 @@
+package ast
+
+import "testing"
+
+func TestRemoveChildren(t *testing.T) {
+	root := NewDocument()
+
+	node1 := NewDocument()
+
+	node2 := NewDocument()
+
+	root.AppendChild(root, node1)
+	root.AppendChild(root, node2)
+
+	root.RemoveChildren(root)
+
+	t.Logf("%+v", node2.PreviousSibling())
+}