1// run
2
3//go:build !nacl && !js && !wasip1 && !gccgo
4
5// Copyright 2019 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// Ensure that deadlock detection can still
10// run even with an import of "_ os/signal".
11
12package main
13
14import (
15	"bytes"
16	"context"
17	"io/ioutil"
18	"log"
19	"os"
20	"os/exec"
21	"path/filepath"
22	"time"
23)
24
25const prog = `
26package main
27
28import _ "os/signal"
29
30func main() {
31  c := make(chan int)
32  c <- 1
33}
34`
35
36func main() {
37	dir, err := ioutil.TempDir("", "21576")
38	if err != nil {
39		log.Fatal(err)
40	}
41	defer os.RemoveAll(dir)
42
43	file := filepath.Join(dir, "main.go")
44	if err := ioutil.WriteFile(file, []byte(prog), 0655); err != nil {
45		log.Fatalf("Write error %v", err)
46	}
47
48	// Using a timeout of 1 minute in case other factors might slow
49	// down the start of "go run". See https://golang.org/issue/34836.
50	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
51	defer cancel()
52
53	cmd := exec.CommandContext(ctx, "go", "run", file)
54	output, err := cmd.CombinedOutput()
55	if err == nil {
56		log.Fatalf("Passed, expected an error")
57	}
58
59	want := []byte("fatal error: all goroutines are asleep - deadlock!")
60	if !bytes.Contains(output, want) {
61		log.Fatalf("Unmatched error message %q:\nin\n%s\nError: %v", want, output, err)
62	}
63}
64