Function TestOneNodeUpInterruptedAuth

tstest/integration/integration_test.go:552–625

If we interrupt `tailscale up` and then run it again, we should only print a single auth URL.

(t *testing.T)

// If we interrupt `tailscale up` and then run it again, we should only
// print a single auth URL.
func TestOneNodeUpInterruptedAuth(t *testing.T) {
	tstest.Parallel(t)

	env := NewTestEnv(t, ConfigureControl(
		func(control *testcontrol.Server) {
			control.RequireAuth = true
			control.AllNodesSameUser = true
		},
	))

	n := NewTestNode(t, env)
	d := n.StartDaemon()
	defer d.MustCleanShutdown(t)

	cmdArgs := []string{"up", "--login-server=" + env.ControlURL()}

	// The first time we run the command, we wait for an auth URL to be
	// printed, and then we cancel the command -- equivalent to ^C.
	//
	// At this point, we've connected to control to get an auth URL,
	// and printed it in the CLI, but not clicked it.
	t.Logf("Running command for the first time: %s", strings.Join(cmdArgs, " "))
	cmd1 := n.Tailscale(cmdArgs...)

	// This handler watches for auth URLs in stdout, then cancels the
	// running `tailscale up` CLI command.
	cmd1.Stdout = &authURLParserWriter{t: t, authURLFn: func(urlStr string) error {
		t.Logf("saw auth URL %q", urlStr)
		cmd1.Process.Kill()
		return nil
	}}
	cmd1.Stderr = cmd1.Stdout

	if err := cmd1.Run(); !isNonZeroExitCode(err) {
		t.Fatalf("Command did not fail with non-zero exit code: %q", err)
	}

	// Because we didn't click the auth URL, we should still be in NeedsLogin.
	n.AwaitBackendState("NeedsLogin")

	// The second time we run the command, we click the first auth URL we see
	// and check that we log in correctly.
	//
	// In #17361, there was a bug where we'd print two auth URLs, and you could
	// click either auth URL and log in to control, but logging in through the
	// first URL would leave `tailscale up` hanging.
	//
	// Using `authURLHandler` ensures we only print the new, correct auth URL.
	//
	// If we print both URLs, it will throw an error because it only expects
	// to log in with one auth URL.
	//
	// If we only print the stale auth URL, the test will timeout because
	// `tailscale up` will never return.
	t.Logf("Running command for the second time: %s", strings.Join(cmdArgs, " "))

	var authURLCount atomic.Int32