btcjson+rpcclient: support new unified softfork bitcoind format

btcjson/chainsvrresults.go

@@ -97,6 +97,30 @@ type Bip9SoftForkDescription struct {
 	Since     int32  `json:"since"`
 }
 
+// SoftForks describes the current softforks enabled by the backend. Softforks
+// activated through BIP9 are grouped together separate from any other softforks
+// with different activation types.
+type SoftForks struct {
+	SoftForks     []*SoftForkDescription              `json:"softforks"`
+	Bip9SoftForks map[string]*Bip9SoftForkDescription `json:"bip9_softforks"`
+}
+
+// UnifiedSoftForks describes a softforks in a general manner, irrespective of
+// its activation type. This was a format introduced by bitcoind v0.19.0
+type UnifiedSoftFork struct {
+	Type                    string                   `json:"type"`
+	BIP9SoftForkDescription *Bip9SoftForkDescription `json:"bip9"`
+	Height                  int32                    `json:"height"`
+	Active                  bool                     `json:"active"`
+}
+
+// UnifiedSoftForks describes the current softforks enabled the by the backend
+// in a unified manner, i.e, softforks with different activation types are
+// grouped together. This was a format introduced by bitcoind v0.19.0
+type UnifiedSoftForks struct {
+	SoftForks map[string]*UnifiedSoftFork `json:"softforks"`
+}
+
 // GetBlockChainInfoResult models the data returned from the getblockchaininfo
 // command.
 type GetBlockChainInfoResult struct {
@@ -110,8 +134,8 @@ type GetBlockChainInfoResult struct {
 	Pruned               bool    `json:"pruned"`
 	PruneHeight          int32   `json:"pruneheight,omitempty"`
 	ChainWork            string  `json:"chainwork,omitempty"`
-	SoftForks            []*SoftForkDescription              `json:"softforks"`
-	Bip9SoftForks        map[string]*Bip9SoftForkDescription `json:"bip9_softforks"`
+	*SoftForks
+	*UnifiedSoftForks
 }
 
 // GetBlockTemplateResultTx models the transactions field of the

integration/bip0009_test.go

@@ -102,7 +102,7 @@ func assertSoftForkStatus(r *rpctest.Harness, t *testing.T, forkKey string, stat
 	}
 
 	// Ensure the key is available.
-	desc, ok := info.Bip9SoftForks[forkKey]
+	desc, ok := info.SoftForks.Bip9SoftForks[forkKey]
 	if !ok {
 		_, _, line, _ := runtime.Caller(1)
 		t.Fatalf("assertion failed at line %d: softfork status for %q "+

rpcclient/chain.go

@@ -253,16 +253,15 @@ func (c *Client) GetDifficulty() (float64, error) {
 
 // FutureGetBlockChainInfoResult is a promise to deliver the result of a
 // GetBlockChainInfoAsync RPC invocation (or an applicable error).
-type FutureGetBlockChainInfoResult chan *response
-
-// Receive waits for the response promised by the future and returns chain info
-// result provided by the server.
-func (r FutureGetBlockChainInfoResult) Receive() (*btcjson.GetBlockChainInfoResult, error) {
-	res, err := receiveFuture(r)
-	if err != nil {
-		return nil, err
-	}
+type FutureGetBlockChainInfoResult struct {
+	client   *Client
+	Response chan *response
+}
 
+// unmarshalPartialGetBlockChainInfoResult unmarshals the response into an
+// instance of GetBlockChainInfoResult without populating the SoftForks and
+// UnifiedSoftForks fields.
+func unmarshalPartialGetBlockChainInfoResult(res []byte) (*btcjson.GetBlockChainInfoResult, error) {
 	var chainInfo btcjson.GetBlockChainInfoResult
 	if err := json.Unmarshal(res, &chainInfo); err != nil {
 		return nil, err
@@ -270,6 +269,59 @@ func (r FutureGetBlockChainInfoResult) Receive() (*btcjson.GetBlockChainInfoResu
 	return &chainInfo, nil
 }
 
+// unmarshalGetBlockChainInfoResultSoftForks properly unmarshals the softforks
+// related fields into the GetBlockChainInfoResult instance.
+func unmarshalGetBlockChainInfoResultSoftForks(chainInfo *btcjson.GetBlockChainInfoResult,
+	version BackendVersion, res []byte) error {
+
+	switch version {
+	// Versions of bitcoind on or after v0.19.0 use the unified format.
+	case BitcoindPost19:
+		var softForks btcjson.UnifiedSoftForks
+		if err := json.Unmarshal(res, &softForks); err != nil {
+			return err
+		}
+		chainInfo.UnifiedSoftForks = &softForks
+
+	// All other versions use the original format.
+	default:
+		var softForks btcjson.SoftForks
+		if err := json.Unmarshal(res, &softForks); err != nil {
+			return err
+		}
+		chainInfo.SoftForks = &softForks
+	}
+
+	return nil
+}
+
+// Receive waits for the response promised by the future and returns chain info
+// result provided by the server.
+func (r FutureGetBlockChainInfoResult) Receive() (*btcjson.GetBlockChainInfoResult, error) {
+	res, err := receiveFuture(r.Response)
+	if err != nil {
+		return nil, err
+	}
+	chainInfo, err := unmarshalPartialGetBlockChainInfoResult(res)
+	if err != nil {
+		return nil, err
+	}
+
+	// Inspect the version to determine how we'll need to parse the
+	// softforks from the response.
+	version, err := r.client.BackendVersion()
+	if err != nil {
+		return nil, err
+	}
+
+	err = unmarshalGetBlockChainInfoResultSoftForks(chainInfo, version, res)
+	if err != nil {
+		return nil, err
+	}
+
+	return chainInfo, nil
+}
+
 // GetBlockChainInfoAsync returns an instance of a type that can be used to get
 // the result of the RPC at some future time by invoking the Receive function
 // on the returned instance.
@@ -277,7 +329,10 @@ func (r FutureGetBlockChainInfoResult) Receive() (*btcjson.GetBlockChainInfoResu
 // See GetBlockChainInfo for the blocking version and more details.
 func (c *Client) GetBlockChainInfoAsync() FutureGetBlockChainInfoResult {
 	cmd := btcjson.NewGetBlockChainInfoCmd()
-	return c.sendCmd(cmd)
+	return FutureGetBlockChainInfoResult{
+		client:   c,
+		Response: c.sendCmd(cmd),
+	}
 }
 
 // GetBlockChainInfo returns information related to the processing state of

rpcclient/chain_test.go

@@ -0,0 +1,92 @@
+package rpcclient
+
+import "testing"
+
+// TestUnmarshalGetBlockChainInfoResult ensures that the SoftForks and
+// UnifiedSoftForks fields of GetBlockChainInfoResult are properly unmarshaled
+// when using the expected backend version.
+func TestUnmarshalGetBlockChainInfoResultSoftForks(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		version    BackendVersion
+		res        []byte
+		compatible bool
+	}{
+		{
+			name:       "bitcoind < 0.19.0 with separate softforks",
+			version:    BitcoindPre19,
+			res:        []byte(`{"softforks": [{"version": 2}]}`),
+			compatible: true,
+		},
+		{
+			name:       "bitcoind >= 0.19.0 with separate softforks",
+			version:    BitcoindPost19,
+			res:        []byte(`{"softforks": [{"version": 2}]}`),
+			compatible: false,
+		},
+		{
+			name:       "bitcoind < 0.19.0 with unified softforks",
+			version:    BitcoindPre19,
+			res:        []byte(`{"softforks": {"segwit": {"type": "bip9"}}}`),
+			compatible: false,
+		},
+		{
+			name:       "bitcoind >= 0.19.0 with unified softforks",
+			version:    BitcoindPost19,
+			res:        []byte(`{"softforks": {"segwit": {"type": "bip9"}}}`),
+			compatible: true,
+		},
+	}
+
+	for _, test := range tests {
+		success := t.Run(test.name, func(t *testing.T) {
+			// We'll start by unmarshaling the JSON into a struct.
+			// The SoftForks and UnifiedSoftForks field should not
+			// be set yet, as they are unmarshaled within a
+			// different function.
+			info, err := unmarshalPartialGetBlockChainInfoResult(test.res)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if info.SoftForks != nil {
+				t.Fatal("expected SoftForks to be empty")
+			}
+			if info.UnifiedSoftForks != nil {
+				t.Fatal("expected UnifiedSoftForks to be empty")
+			}
+
+			// Proceed to unmarshal the softforks of the response
+			// with the expected version. If the version is
+			// incompatible with the response, then this should
+			// fail.
+			err = unmarshalGetBlockChainInfoResultSoftForks(
+				info, test.version, test.res,
+			)
+			if test.compatible && err != nil {
+				t.Fatalf("unable to unmarshal softforks: %v", err)
+			}
+			if !test.compatible && err == nil {
+				t.Fatal("expected to not unmarshal softforks")
+			}
+			if !test.compatible {
+				return
+			}
+
+			// If the version is compatible with the response, we
+			// should expect to see the proper softforks field set.
+			if test.version == BitcoindPost19 &&
+				info.SoftForks != nil {
+				t.Fatal("expected SoftForks to be empty")
+			}
+			if test.version == BitcoindPre19 &&
+				info.UnifiedSoftForks != nil {
+				t.Fatal("expected UnifiedSoftForks to be empty")
+			}
+		})
+		if !success {
+			return
+		}
+	}
+}

rpcserver.go

@@ -1198,14 +1198,16 @@ func handleGetBlockChainInfo(s *rpcServer, cmd interface{}, closeChan <-chan str
 		Difficulty:    getDifficultyRatio(chainSnapshot.Bits, params),
 		MedianTime:    chainSnapshot.MedianTime.Unix(),
 		Pruned:        false,
+		SoftForks: &btcjson.SoftForks{
 			Bip9SoftForks: make(map[string]*btcjson.Bip9SoftForkDescription),
+		},
 	}
 
 	// Next, populate the response with information describing the current
 	// status of soft-forks deployed via the super-majority block
 	// signalling mechanism.
 	height := chainSnapshot.Height
-	chainInfo.SoftForks = []*btcjson.SoftForkDescription{
+	chainInfo.SoftForks.SoftForks = []*btcjson.SoftForkDescription{
 		{
 			ID:      "bip34",
 			Version: 2,
@@ -1281,7 +1283,7 @@ func handleGetBlockChainInfo(s *rpcServer, cmd interface{}, closeChan <-chan str
 
 		// Finally, populate the soft-fork description with all the
 		// information gathered above.
-		chainInfo.Bip9SoftForks[forkName] = &btcjson.Bip9SoftForkDescription{
+		chainInfo.SoftForks.Bip9SoftForks[forkName] = &btcjson.Bip9SoftForkDescription{
 			Status:    strings.ToLower(statusString),
 			Bit:       deploymentDetails.BitNumber,
 			StartTime: int64(deploymentDetails.StartTime),

rpcserverhelp.go

@@ -183,10 +183,7 @@ var helpDescsEnUS = map[string]string{
 	"getblockchaininforesult-pruneheight":          "The lowest block retained in the current pruned chain",
 	"getblockchaininforesult-chainwork":            "The total cumulative work in the best chain",
 	"getblockchaininforesult-softforks":            "The status of the super-majority soft-forks",
-	"getblockchaininforesult-bip9_softforks":        "JSON object describing active BIP0009 deployments",
-	"getblockchaininforesult-bip9_softforks--key":   "bip9_softforks",
-	"getblockchaininforesult-bip9_softforks--value": "An object describing a particular BIP009 deployment",
-	"getblockchaininforesult-bip9_softforks--desc":  "The status of any defined BIP0009 soft-fork deployments",
+	"getblockchaininforesult-unifiedsoftforks":     "The status of the super-majority soft-forks used by bitcoind on or after v0.19.0",
 
 	// SoftForkDescription help.
 	"softforkdescription-reject":  "The current activation status of the softfork",
@@ -194,6 +191,19 @@ var helpDescsEnUS = map[string]string{
 	"softforkdescription-id":      "The string identifier for the soft fork",
 	"-status":                     "A bool which indicates if the soft fork is active",
 
+	// SoftForks help.
+	"softforks-softforks":             "The status of the super-majority soft-forks",
+	"softforks-bip9_softforks":        "JSON object describing active BIP0009 deployments",
+	"softforks-bip9_softforks--key":   "bip9_softforks",
+	"softforks-bip9_softforks--value": "An object describing a particular BIP009 deployment",
+	"softforks-bip9_softforks--desc":  "The status of any defined BIP0009 soft-fork deployments",
+
+	// UnifiedSoftForks help.
+	"unifiedsoftforks-softforks":        "The status of the super-majority soft-forks used by bitcoind on or after v0.19.0",
+	"unifiedsoftforks-softforks--key":   "softforks",
+	"unifiedsoftforks-softforks--value": "An object describing an active softfork deployment used by bitcoind on or after v0.19.0",
+	"unifiedsoftforks-softforks--desc":  "JSON object describing an active softfork deployment used by bitcoind on or after v0.19.0",
+
 	// TxRawResult help.
 	"txrawresult-hex":           "Hex-encoded transaction",
 	"txrawresult-txid":          "The hash of the transaction",