btc: with dcrd's rpcclient, errors are dcrjson.RPCError

With both client and server btc asset backends using dcrd's rpcclient,
the error type from all methods including RawRequest would be
dcrjson.RPCError not btcjson.RPCError.

The numeric codes will still pertain the btcjson constants, even though
the dcrjson.RPCError.Code field is of type dcrjson.RPCErrorCode.

Thus, error matching first interprets the error as a dcrjson.RPCError,
and then compares the int representation of Code to the expected
int code form btcjson.

client/asset/btc/btc.go

@@ -30,6 +30,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/decred/dcrd/dcrjson/v3" // for dcrjson.RPCError returns from rpcclient
 	"github.com/decred/dcrd/rpcclient/v7"
 )
 
@@ -588,10 +589,7 @@ func (btc *ExchangeWallet) Connect(ctx context.Context) (*sync.WaitGroup, error)
 	}
 	// Check for method unknown error for feeRate method.
 	_, err = btc.estimateFee(ctx, btc.node.requester, 1)
-	var rpcErr *btcjson.RPCError
-	if errors.As(err, &rpcErr) &&
-		(rpcErr.Code == btcjson.ErrRPCMethodNotFound.Code || rpcErr.Message == "Method not found") {
-
+	if isMethodNotFoundErr(err) {
 		return nil, fmt.Errorf("fee estimation method not found. Are you configured for the correct RPC?")
 	}
 
@@ -2797,10 +2795,26 @@ func decodeCoinID(coinID dex.Bytes) (*chainhash.Hash, uint32, error) {
 }
 
 // isTxNotFoundErr will return true if the error indicates that the requested
-// transaction is not known.
+// transaction is not known. The error must be dcrjson.RPCError with a numeric
+// code equal to btcjson.ErrRPCNoTxInfo.
 func isTxNotFoundErr(err error) bool {
-	var rpcErr *btcjson.RPCError
-	return errors.As(err, &rpcErr) && rpcErr.Code == btcjson.ErrRPCInvalidAddressOrKey
+	// We are using dcrd's client with Bitcoin Core, so errors will be of type
+	// dcrjson.RPCError, but numeric codes should come from btcjson.
+	const errRPCNoTxInfo = int(btcjson.ErrRPCNoTxInfo)
+	var rpcErr *dcrjson.RPCError
+	return errors.As(err, &rpcErr) && int(rpcErr.Code) == errRPCNoTxInfo
+}
+
+// isMethodNotFoundErr will return true if the error indicates that the RPC
+// method was not found by the RPC server. The error must be dcrjson.RPCError
+// with a numeric code equal to btcjson.ErrRPCMethodNotFound.Code or a message
+// containing "method not found".
+func isMethodNotFoundErr(err error) bool {
+	var errRPCMethodNotFound = int(btcjson.ErrRPCMethodNotFound.Code)
+	var rpcErr *dcrjson.RPCError
+	return errors.As(err, &rpcErr) &&
+		(int(rpcErr.Code) == errRPCMethodNotFound ||
+			strings.Contains(strings.ToLower(rpcErr.Message), "method not found"))
 }
 
 // toBTC returns a float representation in conventional units for the sats.

client/asset/btc/rpcclient.go

@@ -47,7 +47,7 @@ const (
 
 // RawRequester is for sending context-aware RPC requests, and has methods for
 // shutting down the underlying connection.  For testing, it can be satisfied
-// by a stub.
+// by a stub. The returned error should be of type dcrjson.RPCError if non-nil.
 type RawRequester interface {
 	RawRequest(context.Context, string, []json.RawMessage) (json.RawMessage, error)
 }

dex/testing/btc/base-harness.sh

@@ -79,7 +79,7 @@ tmux send-keys -t $SESSION:0 "set +o history" C-m
 tmux send-keys -t $SESSION:0 "cd ${ALPHA_DIR}" C-m
 echo "Starting simnet alpha node"
 tmux send-keys -t $SESSION:0 "${DAEMON} -rpcuser=user -rpcpassword=pass \
-  -rpcport=${ALPHA_RPC_PORT} -datadir=${ALPHA_DIR} \
+  -rpcport=${ALPHA_RPC_PORT} -debug=rpc -datadir=${ALPHA_DIR} \
   -whitelist=127.0.0.0/8 -whitelist=::1 \
   -txindex=1 -regtest=1 -port=${ALPHA_LISTEN_PORT} -fallbackfee=0.00001 \
   ${EXTRA_ARGS}; tmux wait-for -S alpha${SYMBOL}" C-m
@@ -95,7 +95,7 @@ tmux send-keys -t $SESSION:1 "cd ${BETA_DIR}" C-m
 
 echo "Starting simnet beta node"
 tmux send-keys -t $SESSION:1 "${DAEMON} -rpcuser=user -rpcpassword=pass \
-  -rpcport=${BETA_RPC_PORT} -datadir=${BETA_DIR} -txindex=1 -regtest=1 \
+  -rpcport=${BETA_RPC_PORT} -debug=rpc -datadir=${BETA_DIR} -txindex=1 -regtest=1 \
   -whitelist=127.0.0.0/8 -whitelist=::1 \
   -port=${BETA_LISTEN_PORT} -fallbackfee=0.00001 ${EXTRA_ARGS}; \
   tmux wait-for -S beta${SYMBOL}" C-m

server/asset/btc/btc.go

@@ -24,6 +24,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcutil"
+	"github.com/decred/dcrd/dcrjson/v3" // for dcrjson.RPCError returns from rpcclient
 	"github.com/decred/dcrd/rpcclient/v7"
 )
 
@@ -719,11 +720,8 @@ func (btc *Backend) transaction(txHash *chainhash.Hash, verboseTx *btcjson.TxRaw
 func (btc *Backend) getTxOutInfo(txHash *chainhash.Hash, vout uint32) (*btcjson.GetTxOutResult, *btcjson.TxRawResult, []byte, error) {
 	txOut, err := btc.node.GetTxOut(txHash, vout, true)
 	if err != nil {
-		var rpcErr *btcjson.RPCError
-		if errors.As(err, &rpcErr) {
-			if rpcErr.Code == btcjson.ErrRPCInvalidAddressOrKey {
-				return nil, nil, nil, asset.CoinNotFoundError
-			}
+		if isTxNotFoundErr(err) {
+			return nil, nil, nil, asset.CoinNotFoundError
 		}
 		return nil, nil, nil, fmt.Errorf("GetTxOut error for output %s:%d: %w", txHash, vout, err)
 	}
@@ -974,8 +972,11 @@ func toSat(v float64) uint64 {
 // isTxNotFoundErr will return true if the error indicates that the requested
 // transaction is not known.
 func isTxNotFoundErr(err error) bool {
-	var rpcErr *btcjson.RPCError
-	return errors.As(err, &rpcErr) && rpcErr.Code == btcjson.ErrRPCInvalidAddressOrKey
+	// We are using dcrd's client with Bitcoin Core, so errors will be of type
+	// dcrjson.RPCError, but numeric codes should come from btcjson.
+	const errRPCNoTxInfo = int(btcjson.ErrRPCNoTxInfo)
+	var rpcErr *dcrjson.RPCError
+	return errors.As(err, &rpcErr) && int(rpcErr.Code) == errRPCNoTxInfo
 }
 
 // feeRate returns the current optimal fee rate in sat / byte using the

server/asset/btc/rpcclient.go

@@ -23,7 +23,8 @@ const (
 )
 
 // RawRequester is for sending context-aware RPC requests, and has methods for
-// shutting down the underlying connection.
+// shutting down the underlying connection. The returned error should be of type
+// dcrjson.RPCError if non-nil.
 type RawRequester interface {
 	RawRequest(context.Context, string, []json.RawMessage) (json.RawMessage, error)
 	Shutdown()