dont prune too earlyy

proposals/handler.go

@@ -463,7 +463,11 @@ func (h *Handler) checkBallotDataIntegrity(ctx context.Context, b *types.Ballot)
 		if b.EpochData.Beacon == types.EmptyBeacon {
 			return nil, errMissingBeacon
 		}
-		if b.Layer.GetEpoch() == h.clock.CurrentLayer().GetEpoch() {
+		epoch := h.clock.CurrentLayer().GetEpoch()
+		if epoch > 0 {
+			epoch-- // download activesets in the previous epoch too
+		}
+		if b.Layer.GetEpoch() >= epoch {
 			if err := h.fetcher.GetActiveSet(ctx, b.EpochData.ActiveSetHash); err != nil {
 				return nil, err
 			}

prune/prune.go

@@ -85,7 +85,12 @@ func (p *Pruner) Prune(current types.LayerID) error {
 	propTxLatency.Observe(time.Since(start).Seconds())
 	if current.GetEpoch() > p.activesetEpoch {
 		start = time.Now()
-		if err := activesets.DeleteBeforeEpoch(p.db, current.GetEpoch()); err != nil {
+		epoch := current.GetEpoch()
+		if epoch > 0 {
+			epoch--
+		}
+		// current - 1 as activesets will be fetched in hare eligibility oracle
+		if err := activesets.DeleteBeforeEpoch(p.db, epoch); err != nil {
 			return err
 		}
 		activeSetLatency.Observe(time.Since(start).Seconds())

prune/prune_test.go

@@ -83,7 +83,7 @@ func TestPrune(t *testing.T) {
 	for epoch, epochSets := range sets {
 		for _, id := range epochSets {
 			_, err := activesets.Get(db, id)
-			if epoch >= current.GetEpoch() {
+			if epoch >= current.GetEpoch()-1 {
 				require.NoError(t, err)
 			} else {
 				require.ErrorIs(t, err, sql.ErrNotFound)