Build a WindowPoSt disputer

api/api_full.go

@@ -949,7 +949,8 @@ const (
 )
 
 type Deadline struct {
-	PostSubmissions bitfield.BitField
+	PostSubmissions                         bitfield.BitField
+	OptimisticPoStSubmissionsSnapshotLength uint64
 }
 
 type Partition struct {

chain/actors/builtin/miner/miner.go

@@ -106,6 +106,7 @@ type Deadline interface {
 	PartitionsPoSted() (bitfield.BitField, error)
 
 	PartitionsChanged(Deadline) (bool, error)
+	OptimisticPoStSubmissionsSnapshotLength() (uint64, error)
 }
 
 type Partition interface {

chain/actors/builtin/miner/v0.go

@@ -391,6 +391,11 @@ func (d *deadline0) PartitionsPoSted() (bitfield.BitField, error) {
 	return d.Deadline.PostSubmissions, nil
 }
 
+func (d *deadline0) OptimisticPoStSubmissionsSnapshotLength() (uint64, error) {
+	// field doesn't exist until v3
+	return 0, nil
+}
+
 func (p *partition0) AllSectors() (bitfield.BitField, error) {
 	return p.Partition.Sectors, nil
 }

chain/actors/builtin/miner/v2.go

@@ -390,6 +390,11 @@ func (d *deadline2) PartitionsPoSted() (bitfield.BitField, error) {
 	return d.Deadline.PostSubmissions, nil
 }
 
+func (d *deadline2) OptimisticPoStSubmissionsSnapshotLength() (uint64, error) {
+	// field doesn't exist until v3
+	return 0, nil
+}
+
 func (p *partition2) AllSectors() (bitfield.BitField, error) {
 	return p.Partition.Sectors, nil
 }

chain/actors/builtin/miner/v3.go

@@ -386,6 +386,15 @@ func (d *deadline3) PartitionsPoSted() (bitfield.BitField, error) {
 	return d.Deadline.PartitionsPoSted, nil
 }
 
+func (d *deadline3) OptimisticPoStSubmissionsSnapshotLength() (uint64, error) {
+	ops, err := d.OptimisticProofsSnapshotArray(d.store)
+	if err != nil {
+		return 0, err
+	}
+
+	return ops.Length(), nil
+}
+
 func (p *partition3) AllSectors() (bitfield.BitField, error) {
 	return p.Partition.Sectors, nil
 }

cli/chain.go

@@ -58,6 +58,7 @@ var chainCmd = &cli.Command{
 		chainInspectUsage,
 		chainDecodeCmd,
 		chainEncodeCmd,
+		chainDisputeSetCmd,
 	},
 }