stats: hide progress bar for json output (#21871)

changelog/unreleased/issue-21866

@@ -0,0 +1,8 @@
+Bugfix: Hide progress bar for stats command in JSON mode
+
+Since restic 0.19.0, the stats command shows a progress bar. However,
+it was also active when given the `--json` option resulting in text
+mixed with JSON. This has been fixed.
+
+https://github.com/restic/restic/issues/21866
+https://github.com/restic/restic/pull/21871

cmd/restic/cmd_stats.go

@@ -141,7 +141,7 @@ func runStats(ctx context.Context, opts StatsOptions, gopts global.Options, args
 		snapshots = append(snapshots, sn)
 	}
 
-	statsProgress := newStatsProgress(term, uint64(len(snapshots)))
+	statsProgress := newStatsProgress(term, !gopts.JSON, uint64(len(snapshots)))
 
 	updater := progress.NewUpdater(ui.CalculateProgressInterval(!gopts.Quiet, gopts.JSON, term.CanUpdateStatus()), func(runtime time.Duration, final bool) {
 		statsProgress.printProgress(runtime, final)
@@ -375,6 +375,7 @@ type statsProgress struct {
 	term          ui.Terminal
 	m             sync.Mutex
 	snapshotCount uint64
+	show          bool
 
 	processedSnapshotCount uint64
 	processedFileCount     uint64
@@ -382,14 +383,18 @@ type statsProgress struct {
 	processedSize          uint64
 }
 
-func newStatsProgress(term ui.Terminal, snapshotCount uint64) *statsProgress {
+func newStatsProgress(term ui.Terminal, show bool, snapshotCount uint64) *statsProgress {
 	return &statsProgress{
 		term:          term,
+		show:          show,
 		snapshotCount: snapshotCount,
 	}
 }
 
 func (s *statsProgress) printProgress(runtime time.Duration, final bool) {
+	if !s.show {
+		return
+	}
 	s.m.Lock()
 
 	progressBase := s.processedSnapshotCount

cmd/restic/cmd_stats_test.go

@@ -66,7 +66,7 @@ func TestSizeHistogramString(t *testing.T) {
 func TestStatsProgress(t *testing.T) {
 	term := &ui.MockTerminal{}
 
-	progress := newStatsProgress(term, 2)
+	progress := newStatsProgress(term, true, 2)
 	progress.printProgress(0*time.Second, false)
 	rtest.Equals(t, []string{"[0:00] 0.00%  0 / 2 snapshots, 0 B"}, term.Output)
 
@@ -88,3 +88,12 @@ func TestStatsProgress(t *testing.T) {
 	progress.printProgress(20*time.Second, true)
 	rtest.Equals(t, []string{"[0:20] 100.00%  2 / 2 snapshots, 4 files, 5 blobs, 6 B"}, term.Output)
 }
+
+func TestStatsProgressJSON(t *testing.T) {
+	term := &ui.MockTerminal{}
+
+	progress := newStatsProgress(term, false, 2)
+	progress.printProgress(0*time.Second, false)
+	// JSON output is not available yet, so just make sure to not break normal json output
+	rtest.Equals(t, nil, term.Output)
+}