Debian 13 runtime with restic 0.18.1 pinned outside the OS; restic assumptions re-proven; felhom-samba 1.2.0 (R-1105, R-972)

controller/internal/backup/offbox_window.go

@@ -82,7 +82,8 @@ var retentionPolicy = []string{"--group-by", "host,tags",
 	"--keep-daily", strconv.Itoa(keepDaily), "--keep-weekly", strconv.Itoa(keepWeekly), "--keep-monthly", strconv.Itoa(keepMonthly)}
 
 // calendarDaysBefore: how many calendar days s lies before now, both read in s's own zone — the zone
-// restic 0.14.0 buckets a snapshot's day in (the offset stored with the snapshot). Edge, recorded: in the
+// restic buckets a snapshot's day in (the offset stored with the snapshot; 0.14.0, and 0.18.1 gives the same plan on a
+// 502-snapshot, 230-day set made in UTC and Budapest time — R-1105). Edge, recorded: in the
 // hour after local midnight on a DST change, a box whose snapshots carry two different offsets can read one
 // day short; the guard then REFUSES (the safe direction) and the next week's window passes.
 func calendarDaysBefore(s, now time.Time) int {
@@ -182,7 +183,9 @@ func (m *Manager) planRemovals(ctx context.Context, base, env []string) ([]guard
 	if err != nil {
 		return nil, fmt.Errorf("forget --dry-run: %w: %s", err, truncate(out))
 	}
-	// restic 0.14.0 prints the JSON array on stdout; the runner may combine stderr — take the array.
+	// restic prints the JSON array on stdout; the runner may combine stderr — take the array. (R-1105: on 0.18.1 the
+	// plan can be SMALLER than 0.14.0's — while a --keep-monthly window has unused slots it also keeps each group's
+	// oldest snapshot. Only ever more kept; pinned by TestR1105_TheForgetPlanOnlyEverKeepsMore.)
 	js := string(out)
 	if i := strings.Index(js, "["); i > 0 {
 		js = js[i:]