rpc: make helpers handle empty-values for some types

Turns out that protobuf does not send actual nils to handlers if the
request is empty, but always atleast allocates the zero value of said
type before the call. We check for some "required" fields now to determine
if we should return nil or not from the helper

rpc/helpers.go

@@ -174,7 +174,7 @@ func toProtoSongUpdate(s *radio.SongUpdate) *SongUpdate {
 }
 
 func fromProtoSongUpdate(s *SongUpdate) *radio.SongUpdate {
-	if s == nil {
+	if s == nil || (s.Song == nil && s.Info == nil) {
 		return nil
 	}
 	return &radio.SongUpdate{
@@ -214,7 +214,7 @@ func toProtoQueueID(rid radio.QueueID) *QueueID {
 }
 
 func fromProtoQueueID(id *QueueID) radio.QueueID {
-	if id == nil {
+	if id == nil || len(id.ID) == 0 {
 		return radio.QueueID{}
 	}
 
@@ -276,7 +276,7 @@ func toProtoUser(u *radio.User) *User {
 }
 
 func fromProtoUser(u *User) *radio.User {
-	if u == nil {
+	if u == nil || (u.Id == 0 && u.Username == "") {
 		return nil
 	}
 	return &radio.User{

rpc/helpers_test.go

@@ -17,7 +17,7 @@ func TestRoundtrip(tt *testing.T) {
 	// special generator for users since we don't actually pass all the fields
 	// over the wire for reasons
 	userGen := gen.Struct(reflect.TypeFor[radio.User](), map[string]gopter.Gen{
-		"ID":              a.GenForType(reflect.TypeFor[radio.UserID]()),
+		"ID":              a.GenForType(reflect.TypeFor[radio.UserID]()).SuchThat(func(v radio.UserID) bool { return v > 0 }),
 		"Username":        gen.AnyString(),
 		"IP":              gen.AnyString(),
 		"UpdatedAt":       a.GenForType(reflect.TypeFor[*time.Time]()),
@@ -95,7 +95,11 @@ func TestRoundtrip(tt *testing.T) {
 	p.Property("user-permissions", a.ForAll(func(in radio.UserPermissions) bool {
 		out := fromProtoUserPermissions(toProtoUserPermissions(in))
 
-		return assert.Equal(tt, in, out)
+		if len(in) == 0 {
+			return assert.Len(tt, out, 0)
+		} else {
+			return assert.Equal(tt, in, out)
+		}
 	}))
 	p.Property("dj", a.ForAll(func(in radio.DJ) bool {
 		out := fromProtoDJ(toProtoDJ(in))