ui/termstatus: fix clearing status lines

To clear the status lines, they should be set to an empty array to
prevent future updates of those lines. Setting the status lines to an
array containing an empty string is wrong as this causes the output to
continuously add that empty status line after each message.

cmd/restic/progress.go

@@ -53,7 +53,7 @@ func newGenericProgressMax(show bool, max uint64, description string, print func
 func newTerminalProgressMax(show bool, max uint64, description string, term *termstatus.Terminal) *progress.Counter {
 	return newGenericProgressMax(show, max, description, func(status string, final bool) {
 		if final {
-			term.SetStatus([]string{})
+			term.SetStatus(nil)
 			term.Print(status)
 		} else {
 			term.SetStatus([]string{status})

internal/ui/backup/text.go

@@ -121,7 +121,7 @@ func (b *TextProgress) ReportTotal(start time.Time, s archiver.ScanStats) {
 // Reset status
 func (b *TextProgress) Reset() {
 	if b.term.CanUpdateStatus() {
-		b.term.SetStatus([]string{""})
+		b.term.SetStatus(nil)
 	}
 }
 

internal/ui/restore/text.go

@@ -62,7 +62,7 @@ func (t *textPrinter) CompleteItem(messageType ItemAction, item string, size uin
 }
 
 func (t *textPrinter) Finish(p State, duration time.Duration) {
-	t.terminal.SetStatus([]string{})
+	t.terminal.SetStatus(nil)
 
 	timeLeft := ui.FormatDuration(duration)
 	formattedAllBytesTotal := ui.FormatBytes(p.AllBytesTotal)

internal/ui/termstatus/status.go

@@ -315,11 +315,8 @@ func sanitizeLines(lines []string, width int) []string {
 
 // SetStatus updates the status lines.
 // The lines should not contain newlines; this method adds them.
+// Pass nil or an empty array to remove the status lines.
 func (t *Terminal) SetStatus(lines []string) {
-	if len(lines) == 0 {
-		return
-	}
-
 	// only truncate interactive status output
 	var width int
 	if t.canUpdateStatus {

internal/ui/termstatus/status_test.go

@@ -32,6 +32,15 @@ func TestSetStatus(t *testing.T) {
 	term.SetStatus([]string{"first"})
 	exp := home + clear + "first" + home
 
+	term.SetStatus([]string{""})
+	exp += home + clear + "" + home
+
+	term.SetStatus([]string{})
+	exp += home + clear + "" + home
+
+	// already empty status
+	term.SetStatus([]string{})
+
 	term.SetStatus([]string{"foo", "bar", "baz"})
 	exp += home + clear + "foo\n" + home + clear + "bar\n" +
 		home + clear + "baz" + home + up + up