cmd/test2json: add signal handler

Updates #53563

Change-Id: I35a3fd56718e198f68cbf73075a78b2fbc66bd7d
Reviewed-on: https://go-review.googlesource.com/c/go/+/419295
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ryan Schuster <shuey19831@gmail.com>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/go/testdata/script/test2json_interrupt.txt

@@ -0,0 +1,55 @@
+[short] skip 'links and runs a test binary'
+[!fuzz] skip 'tests SIGINT behavior for interrupting fuzz tests'
+[windows] skip 'windows does not support os.Interrupt'
+
+? go test -json -fuzz FuzzInterrupt -run '^$' -parallel 1
+stdout -count=1 '"Action":"pass","Package":"example","Test":"FuzzInterrupt"'
+stdout -count=1 '"Action":"pass","Package":"example","Elapsed":'
+
+mkdir $WORK/fuzzcache
+go test -c . -fuzz=. -o test2json_interrupt_obj
+? go tool test2json -p example -t ./test2json_interrupt_obj -test.v -test.paniconexit0 -test.fuzzcachedir $WORK/fuzzcache -test.fuzz FuzzInterrupt -test.run '^$' -test.parallel 1
+stdout -count=1 '"Action":"pass","Package":"example","Test":"FuzzInterrupt"'
+stdout -count=1 '"Action":"pass","Package":"example","Elapsed":'
+
+-- go.mod --
+module example
+go 1.20
+-- example_test.go --
+package example_test
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"testing"
+	"strings"
+	"time"
+)
+
+func FuzzInterrupt(f *testing.F) {
+	pids := os.Getenv("GO_TEST_INTERRUPT_PIDS")
+	if pids == "" {
+		// This is the main test process.
+		// Set the environment variable for fuzz workers.
+		pid := os.Getpid()
+		ppid := os.Getppid()
+		os.Setenv("GO_TEST_INTERRUPT_PIDS", fmt.Sprintf("%d,%d", ppid, pid))
+	}
+
+	f.Fuzz(func(t *testing.T, orig string) {
+		// Simulate a ctrl-C on the keyboard by sending SIGINT
+		// to the main test process and its parent.
+		for _, pid := range strings.Split(pids, ",") {
+			i, err := strconv.Atoi(pid)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if p, err := os.FindProcess(i); err == nil {
+				p.Signal(os.Interrupt)
+				time.Sleep(10 * time.Millisecond)
+				pids = ""  // Only interrupt once.
+			}
+		}
+	})
+}

src/cmd/test2json/main.go

@@ -88,6 +88,7 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"os/signal"
 
 	"cmd/internal/test2json"
 )
@@ -102,6 +103,11 @@ func usage() {
 	os.Exit(2)
 }
 
+// ignoreSignals ignore the interrupt signals.
+func ignoreSignals() {
+	signal.Ignore(signalsToIgnore...)
+}
+
 func main() {
 	flag.Usage = usage
 	flag.Parse()
@@ -121,6 +127,7 @@ func main() {
 		w := &countWriter{0, c}
 		cmd.Stdout = w
 		cmd.Stderr = w
+		ignoreSignals()
 		err := cmd.Run()
 		if err != nil {
 			if w.n > 0 {

src/cmd/test2json/signal_notunix.go

@@ -0,0 +1,13 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build plan9 || windows
+
+package main
+
+import (
+	"os"
+)
+
+var signalsToIgnore = []os.Signal{os.Interrupt}

src/cmd/test2json/signal_unix.go

@@ -0,0 +1,14 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix || js
+
+package main
+
+import (
+	"os"
+	"syscall"
+)
+
+var signalsToIgnore = []os.Signal{os.Interrupt, syscall.SIGQUIT}