chain: match errors from btcd pre-v0.24.2

chain/btcd.go

@@ -593,6 +593,38 @@ func (c *RPCClient) MapRPCErr(rpcErr error) error {
 		}
 	}
 
+	// If no matching error is found, we try to match it to an older
+	// version of `btcd`.
+	//
+	// Get the backend's version.
+	backend, bErr := c.BackendVersion()
+	if bErr != nil {
+		// If there's an error getting the backend version, we return
+		// the original error and the backend error.
+		return fmt.Errorf("%w: %v, failed to get backend version %v",
+			ErrUndefined, rpcErr, bErr)
+	}
+
+	// If this version supports `testmempoolaccept`, it must be v0.24.2 and
+	// above. In this case, we will return the original error.
+	//
+	// NOTE: `testmempoolaccept` is implemented in v0.24.1, but this
+	// version was never tagged, which means it must be v0.24.2 when it's
+	// supported.
+	if backend.SupportTestMempoolAccept() {
+		// Not matched, return the original error wrapped.
+		return fmt.Errorf("%w: %v", ErrUndefined, rpcErr)
+	}
+
+	// If the backend is older than v0.24.2, we will try to match the error
+	// to the older version of `btcd`.
+	for btcdErr, err := range BtcdErrMapPre2402 {
+		// Match it against btcd's error.
+		if matchErrStr(rpcErr, btcdErr) {
+			return err
+		}
+	}
+
 	// If not matched, return the original error wrapped.
 	return fmt.Errorf("%w: %v", ErrUndefined, rpcErr)
 }

chain/errors.go

@@ -472,6 +472,52 @@ var BtcdErrMap = map[string]error{
 	// "unmatched btcd error 4": ErrSameNonWitnessData,
 }
 
+// BtcdErrMapPre2402 defines the error mapping for btcd versions prior to
+// 0.24.2 - all the errors changed in this commit have been defined here to
+// support older versions:
+// - https://github.com/btcsuite/btcd/pull/2053/commits/ef54c49df443815d50765e8c4f31a87944d950a6
+var BtcdErrMapPre2402 = map[string]error{
+	// A transaction with too large output value.
+	"is higher than max allowed value": ErrLargeOutput,
+
+	// A transaction that conflicts with an unconfirmed tx. Happens when
+	// RBF is not enabled.
+	"already spent by transaction": ErrMempoolConflict,
+
+	// When a transaction causes too many transactions being replaced. This
+	// is set by `MAX_REPLACEMENT_CANDIDATES` in `bitcoind` and defaults to
+	// 100.
+	"evicts more transactions than permitted": ErrTooManyReplacements,
+
+	// A transaction that spends conflicting tx outputs that are rejected.
+	"spends parent transaction": ErrConflictingTx,
+
+	// BIP125 related errors.
+	//
+	// When fee rate used or fees paid doesn't meet the requirements.
+	"has an insufficient fee rate":     ErrInsufficientFee,
+	"has an insufficient absolute fee": ErrInsufficientFee,
+
+	// A transaction in the mempool.
+	"already have transaction": ErrTxAlreadyInMempool,
+
+	// A coinbase transaction.
+	"is an individual coinbase": ErrCoinbaseTx,
+
+	// A transaction already in the blockchain.
+	"transaction already exists": ErrTxAlreadyConfirmed,
+
+	// Some nonstandard transactions - too large tx size.
+	"is larger than max allowed weight of": ErrTxTooLarge,
+
+	// Some nonstandard transactions - too large scriptSig (>1650
+	// bytes).
+	"bytes is larger than max allowed size of": ErrScriptSigSize,
+
+	// Some nonstandard transactions - output too small.
+	"is dust": ErrDust,
+}
+
 // matchErrStr takes an error returned from RPC client and matches it against
 // the specified string. If the expected string pattern is found in the error
 // passed, return true. Both the error strings are normalized before matching.