blockchain: enable v2 to be set (#4597)

* blockchain: enable v2 to be set

- enable v2 to be set via config params

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* replace tab with space

* correctly spell usability

config/toml.go

@@ -321,6 +321,7 @@ max_tx_bytes = {{ .Mempool.MaxTxBytes }}
 # Fast Sync version to use:
 #   1) "v0" (default) - the legacy fast sync implementation
 #   2) "v1" - refactor of v0 version for better testability
+#   3) "v2" - refactor of v1 version for better usability
 version = "{{ .FastSync.Version }}"
 
 ##### consensus configuration options #####

node/node.go

@@ -22,6 +22,7 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	bcv0 "github.com/tendermint/tendermint/blockchain/v0"
 	bcv1 "github.com/tendermint/tendermint/blockchain/v1"
+	bcv2 "github.com/tendermint/tendermint/blockchain/v2"
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/consensus"
 	cs "github.com/tendermint/tendermint/consensus"
@@ -366,6 +367,8 @@ func createBlockchainReactor(config *cfg.Config,
 		bcReactor = bcv0.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
 	case "v1":
 		bcReactor = bcv1.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
+	case "v2":
+		bcReactor = bcv2.NewBlockchainReactor(state.Copy(), blockExec, blockStore, fastSync)
 	default:
 		return nil, fmt.Errorf("unknown fastsync version %s", config.FastSync.Version)
 	}
@@ -1094,6 +1097,8 @@ func makeNodeInfo(
 		bcChannel = bcv0.BlockchainChannel
 	case "v1":
 		bcChannel = bcv1.BlockchainChannel
+	case "v2":
+		bcChannel = bcv2.BlockchainChannel
 	default:
 		return nil, fmt.Errorf("unknown fastsync version %s", config.FastSync.Version)
 	}