From 4d61d73c3ac248409ff9dabff558ec993cc8a25a Mon Sep 17 00:00:00 2001
From: chanxuehong <chanxuehong@gmail.com>
Date: Sat, 18 Sep 2021 16:49:07 +0800
Subject: [PATCH] go/token: fix File.AddLineColumnInfo logic

---
 src/go/token/position.go      |  2 +-
 src/go/token/position_test.go | 95 +++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+), 1 deletion(-)

diff --git a/src/go/token/position.go b/src/go/token/position.go
index b12a8e4086..cbc2ddb5eb 100644
--- a/src/go/token/position.go
+++ b/src/go/token/position.go
@@ -245,7 +245,7 @@ func (f *File) AddLineInfo(offset int, filename string, line int) {
 // information for line directives such as //line filename:line:column.
 func (f *File) AddLineColumnInfo(offset int, filename string, line, column int) {
 	f.mutex.Lock()
-	if i := len(f.infos); i == 0 || f.infos[i-1].Offset < offset && offset < f.size {
+	if i := len(f.infos); (i == 0 || f.infos[i-1].Offset < offset) && offset < f.size {
 		f.infos = append(f.infos, lineInfo{offset, filename, line, column})
 	}
 	f.mutex.Unlock()
diff --git a/src/go/token/position_test.go b/src/go/token/position_test.go
index 10831b2e20..65cb242808 100644
--- a/src/go/token/position_test.go
+++ b/src/go/token/position_test.go
@@ -7,6 +7,7 @@ package token
 import (
 	"fmt"
 	"math/rand"
+	"reflect"
 	"sync"
 	"testing"
 )
@@ -380,3 +381,97 @@ func TestRemoveFile(t *testing.T) {
 	checkPos(bpos3, "fileB:1:4")
 	checkNumFiles(1)
 }
+
+func TestFileAddLineColumnInfo(t *testing.T) {
+	const (
+		filename = "test.go"
+		filesize = 100
+	)
+
+	tests := []struct {
+		name  string
+		infos []lineInfo
+		want  []lineInfo
+	}{
+		{
+			name: "normal",
+			infos: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: 50, Filename: filename, Line: 3, Column: 1},
+				{Offset: 80, Filename: filename, Line: 4, Column: 2},
+			},
+			want: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: 50, Filename: filename, Line: 3, Column: 1},
+				{Offset: 80, Filename: filename, Line: 4, Column: 2},
+			},
+		},
+		{
+			name: "offset1 == file size",
+			infos: []lineInfo{
+				{Offset: filesize, Filename: filename, Line: 2, Column: 1},
+			},
+			want: nil,
+		},
+		{
+			name: "offset1 > file size",
+			infos: []lineInfo{
+				{Offset: filesize + 1, Filename: filename, Line: 2, Column: 1},
+			},
+			want: nil,
+		},
+		{
+			name: "offset2 == file size",
+			infos: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: filesize, Filename: filename, Line: 3, Column: 1},
+			},
+			want: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+			},
+		},
+		{
+			name: "offset2 > file size",
+			infos: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: filesize + 1, Filename: filename, Line: 3, Column: 1},
+			},
+			want: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+			},
+		},
+		{
+			name: "offset2 == offset1",
+			infos: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: 10, Filename: filename, Line: 3, Column: 1},
+			},
+			want: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+			},
+		},
+		{
+			name: "offset2 < offset1",
+			infos: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+				{Offset: 9, Filename: filename, Line: 3, Column: 1},
+			},
+			want: []lineInfo{
+				{Offset: 10, Filename: filename, Line: 2, Column: 1},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			fs := NewFileSet()
+			f := fs.AddFile(filename, -1, filesize)
+			for _, info := range test.infos {
+				f.AddLineColumnInfo(info.Offset, info.Filename, info.Line, info.Column)
+			}
+			if !reflect.DeepEqual(f.infos, test.want) {
+				t.Errorf("\ngot %+v, \nwant %+v", f.infos, test.want)
+			}
+		})
+	}
+}