add standbynodes in GetMasternodesByNumber similar way to subnet

consensus/XDPoS/api.go

@@ -68,6 +68,8 @@ type MasternodesStatus struct {
 	Masternodes     []common.Address
 	PenaltyLen      int
 	Penalty         []common.Address
+	StandbynodesLen int
+	Standbynodes    []common.Address
 	Error           error
 }
 
@@ -144,6 +146,7 @@ func (api *API) GetMasternodesByNumber(number *rpc.BlockNumber) MasternodesStatu
 
 	masterNodes := api.XDPoS.EngineV2.GetMasternodes(api.chain, header)
 	penalties := api.XDPoS.EngineV2.GetPenalties(api.chain, header)
+	standbynodes := api.XDPoS.EngineV2.GetStandbynodes(api.chain, header)
 
 	info := MasternodesStatus{
 		Number:          header.Number.Uint64(),
@@ -152,6 +155,8 @@ func (api *API) GetMasternodesByNumber(number *rpc.BlockNumber) MasternodesStatu
 		Masternodes:     masterNodes,
 		PenaltyLen:      len(penalties),
 		Penalty:         penalties,
+		StandbynodesLen: len(standbynodes),
+		Standbynodes:    standbynodes,
 	}
 	return info
 }

consensus/XDPoS/engines/engine_v2/engine.go

@@ -987,12 +987,21 @@ func (x *XDPoS_v2) GetMasternodes(chain consensus.ChainReader, header *types.Hea
 func (x *XDPoS_v2) GetPenalties(chain consensus.ChainReader, header *types.Header) []common.Address {
 	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, header, header.Hash())
 	if err != nil {
-		log.Error("[GetMasternodes] Adaptor v2 getEpochSwitchInfo has error", "err", err)
+		log.Error("[GetPenalties] Adaptor v2 getEpochSwitchInfo has error", "err", err)
 		return []common.Address{}
 	}
 	return epochSwitchInfo.Penalties
 }
 
+func (x *XDPoS_v2) GetStandbynodes(chain consensus.ChainReader, header *types.Header) []common.Address {
+	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, header, header.Hash())
+	if err != nil {
+		log.Error("[GetStandbynodes] Adaptor v2 getEpochSwitchInfo has error", "err", err)
+		return []common.Address{}
+	}
+	return epochSwitchInfo.Standbynodes
+}
+
 // Calculate masternodes for a block number and parent hash. In V2, truncating candidates[:MaxMasternodes] is done in this function.
 func (x *XDPoS_v2) calcMasternodes(chain consensus.ChainReader, blockNum *big.Int, parentHash common.Hash) ([]common.Address, []common.Address, error) {
 	// using new max masterndoes

consensus/XDPoS/engines/engine_v2/epochSwitch.go

@@ -56,9 +56,24 @@ func (x *XDPoS_v2) getEpochSwitchInfo(chain consensus.ChainReader, header *types
 			log.Error("[getEpochSwitchInfo] get extra field", "err", err, "number", h.Number.Uint64())
 			return nil, err
 		}
+
+		snap, err := x.getSnapshot(chain, header.Number.Uint64(), false)
+		if err != nil {
+			log.Error("[getEpochSwitchInfo] Adaptor v2 getSnapshot has error", "err", err)
+			return nil, err
+		}
 		penalties := common.ExtractAddressFromBytes(h.Penalties)
+		candidates := snap.NextEpochMasterNodes
+		standbynodes := []common.Address{}
+		if len(masternodes) != len(candidates) {
+			standbynodes = candidates
+			standbynodes = common.RemoveItemFromArray(standbynodes, masternodes)
+			standbynodes = common.RemoveItemFromArray(standbynodes, penalties)
+		}
+
 		epochSwitchInfo := &types.EpochSwitchInfo{
 			Penalties:    penalties,
+			Standbynodes: standbynodes,
 			Masternodes:  masternodes,
 			EpochSwitchBlockInfo: &types.BlockInfo{
 				Hash:   hash,

core/types/consensus_v2.go

@@ -112,6 +112,7 @@ func (e *ExtraFields_v2) EncodeToBytes() ([]byte, error) {
 
 type EpochSwitchInfo struct {
 	Penalties                  []common.Address
+	Standbynodes               []common.Address
 	Masternodes                []common.Address
 	EpochSwitchBlockInfo       *BlockInfo
 	EpochSwitchParentBlockInfo *BlockInfo