1// Copyright 2021 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package godebug_test
6
7import (
8	"fmt"
9	. "internal/godebug"
10	"internal/race"
11	"internal/testenv"
12	"os"
13	"os/exec"
14	"reflect"
15	"runtime/metrics"
16	"slices"
17	"strings"
18	"testing"
19)
20
21func TestGet(t *testing.T) {
22	foo := New("#foo")
23	tests := []struct {
24		godebug string
25		setting *Setting
26		want    string
27	}{
28		{"", New("#"), ""},
29		{"", foo, ""},
30		{"foo=bar", foo, "bar"},
31		{"foo=bar,after=x", foo, "bar"},
32		{"before=x,foo=bar,after=x", foo, "bar"},
33		{"before=x,foo=bar", foo, "bar"},
34		{",,,foo=bar,,,", foo, "bar"},
35		{"foodecoy=wrong,foo=bar", foo, "bar"},
36		{"foo=", foo, ""},
37		{"foo", foo, ""},
38		{",foo", foo, ""},
39		{"foo=bar,baz", New("#loooooooong"), ""},
40	}
41	for _, tt := range tests {
42		t.Setenv("GODEBUG", tt.godebug)
43		got := tt.setting.Value()
44		if got != tt.want {
45			t.Errorf("get(%q, %q) = %q; want %q", tt.godebug, tt.setting.Name(), got, tt.want)
46		}
47	}
48}
49
50func TestMetrics(t *testing.T) {
51	const name = "http2client" // must be a real name so runtime will accept it
52
53	var m [1]metrics.Sample
54	m[0].Name = "/godebug/non-default-behavior/" + name + ":events"
55	metrics.Read(m[:])
56	if kind := m[0].Value.Kind(); kind != metrics.KindUint64 {
57		t.Fatalf("NonDefault kind = %v, want uint64", kind)
58	}
59
60	s := New(name)
61	s.Value()
62	s.IncNonDefault()
63	s.IncNonDefault()
64	s.IncNonDefault()
65	metrics.Read(m[:])
66	if kind := m[0].Value.Kind(); kind != metrics.KindUint64 {
67		t.Fatalf("NonDefault kind = %v, want uint64", kind)
68	}
69	if count := m[0].Value.Uint64(); count != 3 {
70		t.Fatalf("NonDefault value = %d, want 3", count)
71	}
72}
73
74// TestPanicNilRace checks for a race in the runtime caused by use of runtime
75// atomics (not visible to usual race detection) to install the counter for
76// non-default panic(nil) semantics.  For #64649.
77func TestPanicNilRace(t *testing.T) {
78	if !race.Enabled {
79		t.Skip("Skipping test intended for use with -race.")
80	}
81	if os.Getenv("GODEBUG") != "panicnil=1" {
82		cmd := testenv.CleanCmdEnv(testenv.Command(t, os.Args[0], "-test.run=^TestPanicNilRace$", "-test.v", "-test.parallel=2", "-test.count=1"))
83		cmd.Env = append(cmd.Env, "GODEBUG=panicnil=1")
84		out, err := cmd.CombinedOutput()
85		t.Logf("output:\n%s", out)
86
87		if err != nil {
88			t.Errorf("Was not expecting a crash")
89		}
90		return
91	}
92
93	test := func(t *testing.T) {
94		t.Parallel()
95		defer func() {
96			recover()
97		}()
98		panic(nil)
99	}
100	t.Run("One", test)
101	t.Run("Two", test)
102}
103
104func TestCmdBisect(t *testing.T) {
105	testenv.MustHaveGoBuild(t)
106	out, err := exec.Command("go", "run", "cmd/vendor/golang.org/x/tools/cmd/bisect", "GODEBUG=buggy=1#PATTERN", os.Args[0], "-test.run=^TestBisectTestCase$").CombinedOutput()
107	if err != nil {
108		t.Fatalf("exec bisect: %v\n%s", err, out)
109	}
110
111	var want []string
112	src, err := os.ReadFile("godebug_test.go")
113	for i, line := range strings.Split(string(src), "\n") {
114		if strings.Contains(line, "BISECT"+" "+"BUG") {
115			want = append(want, fmt.Sprintf("godebug_test.go:%d", i+1))
116		}
117	}
118	slices.Sort(want)
119
120	var have []string
121	for _, line := range strings.Split(string(out), "\n") {
122		if strings.Contains(line, "godebug_test.go:") {
123			have = append(have, line[strings.LastIndex(line, "godebug_test.go:"):])
124		}
125	}
126	slices.Sort(have)
127
128	if !reflect.DeepEqual(have, want) {
129		t.Errorf("bad bisect output:\nhave %v\nwant %v\ncomplete output:\n%s", have, want, string(out))
130	}
131}
132
133// This test does nothing by itself, but you can run
134//
135//	bisect 'GODEBUG=buggy=1#PATTERN' go test -run='^TestBisectTestCase$'
136//
137// to see that the GODEBUG bisect support is working.
138// TestCmdBisect above does exactly that.
139func TestBisectTestCase(t *testing.T) {
140	s := New("#buggy")
141	for i := 0; i < 10; i++ {
142		a := s.Value() == "1"
143		b := s.Value() == "1"
144		c := s.Value() == "1" // BISECT BUG
145		d := s.Value() == "1" // BISECT BUG
146		e := s.Value() == "1" // BISECT BUG
147
148		if a {
149			t.Log("ok")
150		}
151		if b {
152			t.Log("ok")
153		}
154		if c {
155			t.Error("bug")
156		}
157		if d &&
158			e {
159			t.Error("bug")
160		}
161	}
162}
163