server/asset: fail fast if txindex is not enabled for btc clones

This ensures txindex is enabled by fetching information for a coinbase
transaction of a given block which is essential for DEX activities. It is
fatal for btc clone markets if this is not enabled since getrawtransaction
will fail.

dex/networks/btc/script_test.go

@@ -257,7 +257,6 @@ func TestIsDust(t *testing.T) {
 		if res != test.isDust {
 			t.Fatalf("Dust test '%s' failed: want %v got %v",
 				test.name, test.isDust, res)
-			continue
 		}
 	}
 }

dex/networks/dcr/script_test.go

@@ -298,7 +298,6 @@ func TestIsDust(t *testing.T) {
 		if res != test.isDust {
 			t.Fatalf("Dust test '%s' failed: want %v got %v",
 				test.name, test.isDust, res)
-			continue
 		}
 	}
 }

server/asset/btc/btc.go

@@ -368,19 +368,15 @@ func (btc *Backend) Connect(ctx context.Context) (*sync.WaitGroup, error) {
 		}
 	}
 
-	if txindex, err := btc.node.checkTxIndex(); err != nil {
-		if !isMethodNotFoundErr(err) {
-			btc.shutdown()
-			return nil, fmt.Errorf("%s getindexinfo check failed: %w", btc.name, err)
-		}
-		// Ignore and log err if getindexinfo method is not found.
-		// getindexinfo method is not currently supported by
-		// pre 0.21 versions of bitcoind, and some forks of
-		// bitcoin core (litecoin).
-		btc.log.Warnf("The getindexinfo RPC is unavailable. Please ensure txindex is enabled in the node config.")
-	} else if !txindex {
+	txindex, err := btc.node.checkTxIndex()
+	if err != nil {
+		btc.log.Warnf(`Please ensure txindex is enabled in the node config and you might need to re-index if txindex was not previously enabled for %s`, btc.name)
+		btc.shutdown()
+		return nil, fmt.Errorf("error checking txindex for %s: %w", btc.name, err)
+	}
+	if !txindex {
 		btc.shutdown()
-		return nil, fmt.Errorf("%s transaction index is not enabled. Please enable txindex in the node config", btc.name)
+		return nil, fmt.Errorf("%s transaction index is not enabled. Please enable txindex in the node config and you might need to re-index when you enable txindex", btc.name)
 	}
 
 	if _, err = btc.estimateFee(ctx); err != nil {
@@ -648,7 +644,7 @@ func (btc *Backend) TxData(coinID []byte) ([]byte, error) {
 		if isTxNotFoundErr(err) {
 			return nil, asset.CoinNotFoundError
 		}
-		return nil, fmt.Errorf("GetRawTransactionVerbose for txid %s: %w", txHash, err)
+		return nil, fmt.Errorf("GetRawTransaction for txid %s: %w", txHash, err)
 	}
 	return txB, nil
 }

server/asset/btc/rpcclient.go

@@ -29,6 +29,7 @@ const (
 	methodGetIndexInfo      = "getindexinfo"
 	methodGetBlockHeader    = "getblockheader"
 	methodGetBlockStats     = "getblockstats"
+	methodGetBlockHash      = "getblockhash"
 
 	errNoCompetition = dex.ErrorKind("no competition")
 	errNoFeeRate     = dex.ErrorKind("fee rate could not be estimated")
@@ -96,8 +97,8 @@ func (rc *RPCClient) GetBlockChainInfo() (*GetBlockchainInfoResult, error) {
 	return chainInfo, nil
 }
 
-// txIndexResult models the data returned from the getindexinfo command
-// for txindex.
+// txIndexResult models the data returned from the getindexinfo command for
+// txindex.
 // txIndexResult.Txindex is nil if the returned data is an empty json object.
 type txIndexResult struct {
 	TxIndex *struct{} `json:"txindex"`
@@ -107,12 +108,55 @@ type txIndexResult struct {
 func (rc *RPCClient) checkTxIndex() (bool, error) {
 	res := new(txIndexResult)
 	err := rc.call(methodGetIndexInfo, anylist{"txindex"}, res)
+	if err == nil {
+		// Return early if there is no error. bitcoind returns an empty json
+		// object if txindex is not enabled. It is safe to conclude txindex is
+		// enabled if res.Txindex is not nil.
+		return res.TxIndex != nil, nil
+	}
+
+	if !isMethodNotFoundErr(err) {
+		return false, err
+	}
+
+	// Using block at index 5 to retrieve a coinbase transaction and ensure
+	// txindex is enabled for pre 0.21 versions of bitcoind.
+	const blockIndex = 5
+	blockHash, err := rc.getBlockHash(blockIndex)
+	if err != nil {
+		return false, err
+	}
+
+	blockInfo, err := rc.GetBlockVerbose(blockHash)
+	if err != nil {
+		return false, err
+	}
+
+	if len(blockInfo.Tx) == 0 {
+		return false, fmt.Errorf("block %d does not have a coinbase transaction", blockIndex)
+	}
+
+	txHash, err := chainhash.NewHashFromStr(blockInfo.Tx[0])
+	if err != nil {
+		return false, err
+	}
+
+	// Retrieve coinbase transaction information.
+	txBytes, err := rc.GetRawTransaction(txHash)
 	if err != nil {
 		return false, err
 	}
-	// bitcoind returns an empty json object if txindex is not enabled.
-	// It is safe to conclude txindex is enabled if res.Txindex is not nil.
-	return res.TxIndex != nil, nil
+
+	return len(txBytes) != 0, nil
+}
+
+// getBlockHash fetches the block hash for the block at the given index.
+func (rc *RPCClient) getBlockHash(index int64) (*chainhash.Hash, error) {
+	var blockHashStr string
+	if err := rc.call(methodGetBlockHash, anylist{index}, &blockHashStr); err != nil {
+		return nil, err
+	}
+	return chainhash.NewHashFromStr(blockHashStr)
 }
 
 // EstimateSmartFee requests the server to estimate a fee level.

server/dex/dex.go

@@ -695,7 +695,7 @@ func NewDEX(ctx context.Context, cfg *DexConf) (*DEX, error) {
 	// Because the dexBalancer relies on the marketTunnels map, and NewMarket
 	// checks necessary balances for account-based assets using the dexBalancer,
 	// that means that each market can only query orders for the markets that
-	// were intitialized before it was, which is fine, but notable. The
+	// were initialized before it was, which is fine, but notable. The
 	// resulting behavior is that a user could have orders involving an
 	// account-based asset approved for re-booking on one market, but have
 	// orders rejected on a market involving the same asset created afterwards,