tailcfg: remove ancient UserProfiles.Roles field

And add omitempty to the ProfilePicURL too while here. Plenty
of users (and tagged devices) don't have profile pics.

Updates #14988

Change-Id: I6534bc14edb58fe1034d2d35ae2395f09fd7dd0d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tailcfg/tailcfg.go

@@ -259,11 +259,7 @@ type UserProfile struct {
 	ID            UserID
 	LoginName     string // "alice@smith.com"; for display purposes only (provider is not listed)
 	DisplayName   string // "Alice Smith"
-	ProfilePicURL string
+	ProfilePicURL string `json:",omitempty"`
-
-	// Roles exists for legacy reasons, to keep old macOS clients
-	// happy. It JSON marshals as [].
-	Roles emptyStructJSONSlice
 }
 
 func (p *UserProfile) Equal(p2 *UserProfile) bool {
@@ -279,16 +275,6 @@ func (p *UserProfile) Equal(p2 *UserProfile) bool {
 		p.ProfilePicURL == p2.ProfilePicURL
 }
 
-type emptyStructJSONSlice struct{}
-
-var emptyJSONSliceBytes = []byte("[]")
-
-func (emptyStructJSONSlice) MarshalJSON() ([]byte, error) {
-	return emptyJSONSliceBytes, nil
-}
-
-func (emptyStructJSONSlice) UnmarshalJSON([]byte) error { return nil }
-
 // RawMessage is a raw encoded JSON value. It implements Marshaler and
 // Unmarshaler and can be used to delay JSON decoding or precompute a JSON
 // encoding.

tailcfg/tailcfg_clone.go

@@ -623,7 +623,6 @@ var _UserProfileCloneNeedsRegeneration = UserProfile(struct {
 	LoginName     string
 	DisplayName   string
 	ProfilePicURL string
-	Roles         emptyStructJSONSlice
 }{})
 
 // Clone duplicates src into dst and reports whether it succeeded.

tailcfg/tailcfg_test.go

@@ -10,7 +10,6 @@ import (
 	"reflect"
 	"regexp"
 	"strconv"
-	"strings"
 	"testing"
 	"time"
 
@@ -649,28 +648,6 @@ func TestCloneNode(t *testing.T) {
 	}
 }
 
-func TestUserProfileJSONMarshalForMac(t *testing.T) {
-	// Old macOS clients had a bug where they required
-	// UserProfile.Roles to be non-null. Lock that in
-	// 1.0.x/1.2.x clients are gone in the wild.
-	// See mac commit 0242c08a2ca496958027db1208f44251bff8488b (Sep 30).
-	// It was fixed in at least 1.4.x, and perhaps 1.2.x.
-	j, err := json.Marshal(UserProfile{})
-	if err != nil {
-		t.Fatal(err)
-	}
-	const wantSub = `"Roles":[]`
-	if !strings.Contains(string(j), wantSub) {
-		t.Fatalf("didn't contain %#q; got: %s", wantSub, j)
-	}
-
-	// And back:
-	var up UserProfile
-	if err := json.Unmarshal(j, &up); err != nil {
-		t.Fatalf("Unmarshal: %v", err)
-	}
-}
-
 func TestEndpointTypeMarshal(t *testing.T) {
 	eps := []EndpointType{
 		EndpointUnknownType,

tailcfg/tailcfg_view.go

@@ -1403,7 +1403,6 @@ func (v UserProfileView) ID() UserID                    { return v.ж.ID }
 func (v UserProfileView) LoginName() string             { return v.ж.LoginName }
 func (v UserProfileView) DisplayName() string           { return v.ж.DisplayName }
 func (v UserProfileView) ProfilePicURL() string         { return v.ж.ProfilePicURL }
-func (v UserProfileView) Roles() emptyStructJSONSlice   { return v.ж.Roles }
 func (v UserProfileView) Equal(v2 UserProfileView) bool { return v.ж.Equal(v2.ж) }
 
 // A compilation failure here means this code must be regenerated, with the command at the top of this file.
@@ -1412,5 +1411,4 @@ var _UserProfileViewNeedsRegeneration = UserProfile(struct {
 	LoginName     string
 	DisplayName   string
 	ProfilePicURL string
-	Roles         emptyStructJSONSlice
 }{})