1// run
2
3//go:build !nacl && !js && !wasip1 && gc
4
5// Copyright 2015 The Go Authors. All rights reserved.
6// Use of this source code is governed by a BSD-style
7// license that can be found in the LICENSE file.
8
9// Issue 11771: Magic comments should ignore carriage returns.
10
11package main
12
13import (
14	"bytes"
15	"fmt"
16	"io/ioutil"
17	"log"
18	"os"
19	"os/exec"
20	"path/filepath"
21	"runtime"
22)
23
24func main() {
25	if runtime.Compiler != "gc" {
26		return
27	}
28
29	dir, err := ioutil.TempDir("", "go-issue11771")
30	if err != nil {
31		log.Fatalf("creating temp dir: %v\n", err)
32	}
33	defer os.RemoveAll(dir)
34
35	// The go:nowritebarrier magic comment is only permitted in
36	// the runtime package.  So we confirm that the compilation
37	// fails.
38
39	var buf bytes.Buffer
40	fmt.Fprintln(&buf, `
41package main
42
43func main() {
44}
45`)
46	fmt.Fprintln(&buf, "//go:nowritebarrier\r")
47	fmt.Fprintln(&buf, `
48func x() {
49}
50`)
51
52	if err := ioutil.WriteFile(filepath.Join(dir, "x.go"), buf.Bytes(), 0666); err != nil {
53		log.Fatal(err)
54	}
55
56	cmd := exec.Command("go", "tool", "compile", "-p=p", "x.go")
57	cmd.Dir = dir
58	output, err := cmd.CombinedOutput()
59	if err == nil {
60		log.Fatal("compile succeeded unexpectedly")
61	}
62	if !bytes.Contains(output, []byte("only allowed in runtime")) {
63		log.Fatalf("wrong error message from compiler; got:\n%s\n", output)
64	}
65}
66