rpcsrv: return more configuration data to the client

These are extensions, but they're important for the client to make various
decisions.

docs/rpc.md

@@ -162,6 +162,15 @@ latest state synchronization point P the node working against,
 `LastUpdatedBlock` equals P. For NEP-11 NFTs `LastUpdatedBlock` is equal for
 all tokens of the same asset.
 
+##### `getversion`
+
+NeoGo can return additional fields in the `protocol` object depending on the
+extensions enabled. Specifically that's `p2psigextensions` and
+`staterootinheader` booleans and `committeehistory` and `validatorshistory`
+objects (that are effectively maps from stringified integers to other
+integers. These fields are only returned when corresponding settings are
+enabled in the server's protocol configuration.
+
 ##### `getnep11transfers` and `getnep17transfers`
 `transfernotifyindex` is not tracked by NeoGo, thus this field is always zero.
 

pkg/neorpc/result/version.go

@@ -39,8 +39,18 @@ type (
 		MemoryPoolMaxTransactions   int
 		ValidatorsCount             byte
 		InitialGasDistribution      fixedn.Fixed8
+
+		// Below are NeoGo-specific extensions to the protocol that are
+		// returned by the server in case they're enabled.
+
+		// CommitteeHistory stores height:size map of the committee size.
+		CommitteeHistory map[uint32]int
+		// P2PSigExtensions is true when Notary subsystem is enabled on the network.
+		P2PSigExtensions bool
 		// StateRootInHeader is true if state root is contained in block header.
 		StateRootInHeader bool
+		// ValidatorsHistory stores height:size map of the validators count.
+		ValidatorsHistory map[uint32]int
 	}
 )
 
@@ -67,7 +77,11 @@ type (
 		MemoryPoolMaxTransactions   int           `json:"memorypoolmaxtransactions"`
 		ValidatorsCount             byte          `json:"validatorscount"`
 		InitialGasDistribution      int64         `json:"initialgasdistribution"`
+
+		CommitteeHistory  map[uint32]int `json:"committeehistory,omitempty"`
+		P2PSigExtensions  bool           `json:"p2psigextensions,omitempty"`
 		StateRootInHeader bool           `json:"staterootinheader,omitempty"`
+		ValidatorsHistory map[uint32]int `json:"validatorshistory,omitempty"`
 	}
 
 	// versionUnmarshallerAux is an auxiliary struct used for Version JSON unmarshalling.
@@ -92,7 +106,11 @@ type (
 		MemoryPoolMaxTransactions   int             `json:"memorypoolmaxtransactions"`
 		ValidatorsCount             byte            `json:"validatorscount"`
 		InitialGasDistribution      json.RawMessage `json:"initialgasdistribution"`
+
+		CommitteeHistory  map[uint32]int `json:"committeehistory,omitempty"`
+		P2PSigExtensions  bool           `json:"p2psigextensions,omitempty"`
 		StateRootInHeader bool           `json:"staterootinheader,omitempty"`
+		ValidatorsHistory map[uint32]int `json:"validatorshistory,omitempty"`
 	}
 )
 
@@ -118,7 +136,11 @@ func (v *Version) MarshalJSON() ([]byte, error) {
 			MemoryPoolMaxTransactions:   v.Protocol.MemoryPoolMaxTransactions,
 			ValidatorsCount:             v.Protocol.ValidatorsCount,
 			InitialGasDistribution:      int64(v.Protocol.InitialGasDistribution),
+
+			CommitteeHistory:  v.Protocol.CommitteeHistory,
+			P2PSigExtensions:  v.Protocol.P2PSigExtensions,
 			StateRootInHeader: v.Protocol.StateRootInHeader,
+			ValidatorsHistory: v.Protocol.ValidatorsHistory,
 		},
 		StateRootInHeader: v.StateRootInHeader,
 	}
@@ -145,7 +167,10 @@ func (v *Version) UnmarshalJSON(data []byte) error {
 	v.Protocol.MaxTransactionsPerBlock = aux.Protocol.MaxTransactionsPerBlock
 	v.Protocol.MemoryPoolMaxTransactions = aux.Protocol.MemoryPoolMaxTransactions
 	v.Protocol.ValidatorsCount = aux.Protocol.ValidatorsCount
+	v.Protocol.CommitteeHistory = aux.Protocol.CommitteeHistory
+	v.Protocol.P2PSigExtensions = aux.Protocol.P2PSigExtensions
 	v.Protocol.StateRootInHeader = aux.Protocol.StateRootInHeader
+	v.Protocol.ValidatorsHistory = aux.Protocol.ValidatorsHistory
 	v.StateRootInHeader = aux.StateRootInHeader
 	if len(aux.Protocol.InitialGasDistribution) == 0 {
 		return nil

pkg/services/rpcsrv/server.go

@@ -694,7 +694,11 @@ func (s *Server) getVersion(_ params.Params) (interface{}, *neorpc.Error) {
 			MemoryPoolMaxTransactions:   cfg.MemPoolSize,
 			ValidatorsCount:             byte(cfg.GetNumOfCNs(s.chain.BlockHeight())),
 			InitialGasDistribution:      cfg.InitialGASSupply,
+
+			CommitteeHistory:  cfg.CommitteeHistory,
+			P2PSigExtensions:  cfg.P2PSigExtensions,
 			StateRootInHeader: cfg.StateRootInHeader,
+			ValidatorsHistory: cfg.ValidatorsHistory,
 		},
 	}, nil
 }

pkg/services/rpcsrv/server_test.go

@@ -875,7 +875,11 @@ var rpcTestCases = map[string][]rpcTestCase{
 				require.EqualValues(t, cfg.MemPoolSize, resp.Protocol.MemoryPoolMaxTransactions)
 				require.EqualValues(t, cfg.ValidatorsCount, resp.Protocol.ValidatorsCount)
 				require.EqualValues(t, cfg.InitialGASSupply, resp.Protocol.InitialGasDistribution)
-				require.EqualValues(t, false, resp.Protocol.StateRootInHeader)
+
+				require.Equal(t, 0, len(resp.Protocol.CommitteeHistory))
+				require.True(t, resp.Protocol.P2PSigExtensions) // Yeah, notary is enabled.
+				require.False(t, resp.Protocol.StateRootInHeader)
+				require.Equal(t, 0, len(resp.Protocol.ValidatorsHistory))
 			},
 		},
 	},