From 75a8a011dbd889f7d0095484e8ea4b883d6e1f80 Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Fri, 12 Jun 2020 15:37:31 +0900
Subject: [PATCH] Fix processing of PrintErrorToken ( clone token.Token )
 reason: Currently, PrintErrorToken make disruptive changes token.Token

---
 printer/printer.go | 20 ++++++++++++--------
 token/token.go     | 13 +++++++++++++
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/printer/printer.go b/printer/printer.go
index b540524e..bc3d7232 100644
--- a/printer/printer.go
+++ b/printer/printer.go
@@ -255,7 +255,7 @@ func (p *Printer) printBeforeTokens(tk *token.Token, minLine, extLine int) token
 		}
 		tk = tk.Prev
 	}
-	minTk := tk
+	minTk := tk.Clone()
 	if minTk.Prev != nil {
 		// add white spaces to minTk by prev token
 		prev := minTk.Prev
@@ -266,8 +266,9 @@ func (p *Printer) printBeforeTokens(tk *token.Token, minLine, extLine int) token
 	tokens := token.Tokens{minTk}
 	tk = minTk.Next
 	for tk != nil && tk.Position.Line <= extLine {
-		tokens.Add(tk)
-		tk = tk.Next
+		clonedTk := tk.Clone()
+		tokens.Add(clonedTk)
+		tk = clonedTk.Next
 	}
 	lastTk := tokens[len(tokens)-1]
 	trimmedOrigin := p.removeRightSideWhiteSpaceChar(lastTk.Origin)
@@ -275,11 +276,13 @@ func (p *Printer) printBeforeTokens(tk *token.Token, minLine, extLine int) token
 	lastTk.Origin = trimmedOrigin
 
 	if lastTk.Next != nil && len(suffix) > 1 {
+		next := lastTk.Next.Clone()
 		// add suffix to header of next token
 		if suffix[0] == '\n' || suffix[0] == '\r' {
 			suffix = suffix[1:]
 		}
-		lastTk.Next.Origin = suffix + lastTk.Next.Origin
+		next.Origin = suffix + next.Origin
+		lastTk.Next = next
 	}
 	return tokens
 }
@@ -307,14 +310,15 @@ func (p *Printer) printAfterTokens(tk *token.Token, maxLine int) token.Tokens {
 	if tk.Position.Line > maxLine {
 		return tokens
 	}
-	minTk := tk
+	minTk := tk.Clone()
 	minTk.Origin = p.removeLeftSideNewLineChar(minTk.Origin)
 	tokens.Add(minTk)
 	tk = minTk.Next
 	for tk != nil && tk.Position.Line <= maxLine {
-		p.addNewLineCharIfDocumentHeader(tk)
-		tokens.Add(tk)
-		tk = tk.Next
+		clonedTk := tk.Clone()
+		p.addNewLineCharIfDocumentHeader(clonedTk)
+		tokens.Add(clonedTk)
+		tk = clonedTk.Next
 	}
 	return tokens
 }
diff --git a/token/token.go b/token/token.go
index 1016d8f6..860db4a7 100644
--- a/token/token.go
+++ b/token/token.go
@@ -681,6 +681,19 @@ func (t *Token) AddColumn(col int) {
 	t.Position.Column += col
 }
 
+// Clone copy token ( preserve Prev/Next reference )
+func (t *Token) Clone() *Token {
+	if t == nil {
+		return nil
+	}
+	copied := *t
+	if t.Position != nil {
+		pos := *(t.Position)
+		copied.Position = &pos
+	}
+	return &copied
+}
+
 // Tokens type of token collection
 type Tokens []*Token