From f6e3240dee0da2f6772de8aac9c776b22ca4818a Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Fri, 30 Apr 2021 13:29:06 -0700
Subject: [PATCH] cmd/tailscale/cli: add test to catch ipn.Pref additions

---
 cmd/tailscale/cli/cli_test.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/cmd/tailscale/cli/cli_test.go b/cmd/tailscale/cli/cli_test.go
index 9f43d2fad..2456c1e83 100644
--- a/cmd/tailscale/cli/cli_test.go
+++ b/cmd/tailscale/cli/cli_test.go
@@ -9,6 +9,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"reflect"
 	"strings"
 	"testing"
 
@@ -553,3 +554,26 @@ func TestPrefsFromUpArgs(t *testing.T) {
 	}
 
 }
+
+func TestPrefFlagMapping(t *testing.T) {
+	prefType := reflect.TypeOf(ipn.Prefs{})
+	for i := 0; i < prefType.NumField(); i++ {
+		prefName := prefType.Field(i).Name
+		if _, ok := flagForPref[prefName]; ok {
+			continue
+		}
+		switch prefName {
+		case "WantRunning", "Persist", "LoggedOut":
+			// All explicitly handled (ignored) by checkForAccidentalSettingReverts.
+			continue
+		case "OSVersion", "DeviceModel":
+			// Only used by Android, which doesn't have a CLI mode anyway, so
+			// fine to not map.
+			continue
+		case "NotepadURLs":
+			// TODO(bradfitz): https://github.com/tailscale/tailscale/issues/1830
+			continue
+		}
+		t.Errorf("unexpected new ipn.Pref field %q is not handled by up.go (see addPrefFlagMapping and checkForAccidentalSettingReverts)", prefName)
+	}
+}