[WIP] test mining on a forked chain

chain/checkpoint.go

@@ -13,6 +13,12 @@ func (syncer *Syncer) SyncCheckpoint(ctx context.Context, tsk types.TipSetKey) e
 		return xerrors.Errorf("called with empty tsk")
 	}
 
+	// XXX: I think this change here is correct (we won't have a tipset unless we have all parents) but:
+	// 1. I'm not sure.
+	// 2. The sync code is dumb and should look at what we have. Actually, it does look at what
+	// we have... then it seems to ignore it?
+	//
+	// Without this change, the test fails because we can't sync the chain we already have!
 	ts, err := syncer.ChainStore().LoadTipSet(ctx, tsk)
 	if err != nil {
 		tss, err := syncer.Exchange.GetBlocks(ctx, tsk, 1)
@@ -22,18 +28,18 @@ func (syncer *Syncer) SyncCheckpoint(ctx context.Context, tsk types.TipSetKey) e
 			return xerrors.Errorf("expected 1 tipset, got %d", len(tss))
 		}
 		ts = tss[0]
-	}
 
-	hts := syncer.ChainStore().GetHeaviestTipSet()
-	if !hts.Equals(ts) {
-		if anc, err := syncer.store.IsAncestorOf(ctx, ts, hts); err != nil {
-			return xerrors.Errorf("failed to walk the chain when checkpointing: %w", err)
-		} else if !anc {
-			if err := syncer.collectChain(ctx, ts, hts, true); err != nil {
-				return xerrors.Errorf("failed to collect chain for checkpoint: %w", err)
-			}
-		} // else new checkpoint is on the current chain, we definitely have the tipsets.
-	} // else current head, no need to switch.
+		hts := syncer.ChainStore().GetHeaviestTipSet()
+		if !hts.Equals(ts) {
+			if anc, err := syncer.store.IsAncestorOf(ctx, ts, hts); err != nil {
+				return xerrors.Errorf("failed to walk the chain when checkpointing: %w", err)
+			} else if !anc {
+				if err := syncer.collectChain(ctx, ts, hts, true); err != nil {
+					return xerrors.Errorf("failed to collect chain for checkpoint: %w", err)
+				}
+			} // else new checkpoint is on the current chain, we definitely have the tipsets.
+		} // else current head, no need to switch.
+	}
 
 	if err := syncer.ChainStore().SetCheckpoint(ctx, ts); err != nil {
 		return xerrors.Errorf("failed to set the chain checkpoint: %w", err)

itests/checkpoint_test.go

@@ -0,0 +1,61 @@
+package itests
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/filecoin-project/go-state-types/abi"
+	"github.com/filecoin-project/lotus/chain/types"
+	"github.com/filecoin-project/lotus/itests/kit"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCheckpointFork(t *testing.T) {
+	ctx := context.Background()
+
+	blocktime := 100 * time.Millisecond
+	// Create three miners.
+	miners := make([]*kit.TestMiner, 3)
+	n1, ens := kit.EnsembleOneMany(t,
+		miners,
+		kit.MockProofs(),
+		kit.ThroughRPC(),
+	)
+
+	// Start 2 of them.
+	ens.InterconnectAll().BeginMining(blocktime, miners[:2]...)
+
+	{
+		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+		n1.WaitTillChain(ctx, kit.HeightAtLeast(abi.ChainEpoch(5)))
+		cancel()
+	}
+
+	// Wait till both participate in a single tipset.
+	var target *types.TipSet
+	{
+		// find the first tipset where two miners mine a block.
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+		target = n1.WaitTillChain(ctx, func(ts *types.TipSet) bool {
+			return len(ts.Blocks()) == 2
+		})
+		cancel()
+	}
+
+	// Wait till we've moved on from that tipset.
+	targetHeight := target.Height() + 10
+	n1.WaitTillChain(ctx, kit.HeightAtLeast(targetHeight))
+
+	// Forcibly sync to this fork tipset.
+	forkTs, err := types.NewTipSet(target.Blocks()[:1])
+	require.NoError(t, err)
+	require.NoError(t, n1.SyncCheckpoint(ctx, forkTs.Key()))
+	ens.BeginMining(blocktime, miners[2])
+
+	// See if we can start making progress again!
+	newHead := n1.WaitTillChain(ctx, kit.HeightAtLeast(targetHeight))
+	forkTs2, err := n1.ChainGetTipSetByHeight(ctx, forkTs.Height(), newHead.Key())
+	require.NoError(t, err)
+	require.True(t, forkTs.Equals(forkTs2))
+}

itests/kit/ensemble_presets.go

@@ -77,6 +77,28 @@ func EnsembleOneTwo(t *testing.T, opts ...interface{}) (*TestFullNode, *TestMine
 	return &full, &one, &two, ens
 }
 
+// EnsembleOneMany and starts an Ensemble with one full node and fills the miner slice with miners.
+// It does not interconnect nodes nor does it begin mining.
+//
+// This function supports passing both ensemble and node functional options.
+// Functional options are applied to all nodes.
+func EnsembleOneMany(t *testing.T, miners []*TestMiner, opts ...interface{}) (*TestFullNode, *Ensemble) {
+	opts = append(opts, WithAllSubsystems())
+
+	eopts, nopts := siftOptions(t, opts)
+
+	var full TestFullNode
+	ens := NewEnsemble(t, eopts...).FullNode(&full, nopts...)
+	for i := range miners {
+		var m TestMiner
+		ens.Miner(&m, &full, nopts...)
+		miners[i] = &m
+	}
+	ens.Start()
+
+	return &full, ens
+}
+
 func siftOptions(t *testing.T, opts []interface{}) (eopts []EnsembleOpt, nopts []NodeOpt) {
 	for _, v := range opts {
 		switch o := v.(type) {

miner/miner.go

@@ -348,18 +348,24 @@ minerLoop:
 				if err != nil {
 					log.Errorf("<!!> SLASH FILTER ERRORED: %s", err)
 					// Continue here, because it's _probably_ wiser to not submit this block
+					base.NullRounds++
+					// XXX: WAIT?
 					continue
 				}
 
 				if fault {
 					log.Errorf("<!!> SLASH FILTER DETECTED FAULT due to blocks %s and %s", b.Header.Cid(), witness)
+					base.NullRounds++
+					// XXX: WAIT?
 					continue
 				}
 			}
 
 			// Check for blocks created at the same height.
 			if _, ok := m.minedBlockHeights.Get(b.Header.Height); ok {
 				log.Warnw("Created a block at the same height as another block we've created", "height", b.Header.Height, "miner", b.Header.Miner, "parents", b.Header.Parents)
+				base.NullRounds++
+				// XXX: WAIT?
 				continue
 			}