multi: replace usage of BuildMerkleTreeStore with CalcMerkleRoot

blockchain/fullblocktests/generate.go

@@ -309,8 +309,7 @@ func calcMerkleRoot(txns []*wire.MsgTx) chainhash.Hash {
 	for _, tx := range txns {
 		utilTxns = append(utilTxns, btcutil.NewTx(tx))
 	}
-	merkles := blockchain.BuildMerkleTreeStore(utilTxns, false)
-	return *merkles[len(merkles)-1]
+	return blockchain.CalcMerkleRoot(utilTxns, false)
 }
 
 // solveBlock attempts to find a nonce which makes the passed block header hash

blockchain/merkle.go

@@ -301,8 +301,7 @@ func ValidateWitnessCommitment(blk *btcutil.Block) error {
 	// the extracted witnessCommitment is equal to:
 	// SHA256(witnessMerkleRoot || witnessNonce). Where witnessNonce is the
 	// coinbase transaction's only witness item.
-	witnessMerkleTree := BuildMerkleTreeStore(blk.Transactions(), true)
-	witnessMerkleRoot := witnessMerkleTree[len(witnessMerkleTree)-1]
+	witnessMerkleRoot := CalcMerkleRoot(blk.Transactions(), true)
 
 	var witnessPreimage [chainhash.HashSize * 2]byte
 	copy(witnessPreimage[:], witnessMerkleRoot[:])

blockchain/validate.go

@@ -527,12 +527,11 @@ func checkBlockSanity(block *btcutil.Block, powLimit *big.Int, timeSource Median
 	// checks.  Bitcoind builds the tree here and checks the merkle root
 	// after the following checks, but there is no reason not to check the
 	// merkle root matches here.
-	merkles := BuildMerkleTreeStore(block.Transactions(), false)
-	calculatedMerkleRoot := merkles[len(merkles)-1]
-	if !header.MerkleRoot.IsEqual(calculatedMerkleRoot) {
+	calcMerkleRoot := CalcMerkleRoot(block.Transactions(), false)
+	if !header.MerkleRoot.IsEqual(&calcMerkleRoot) {
 		str := fmt.Sprintf("block merkle root is invalid - block "+
 			"header indicates %v, but calculated value is %v",
-			header.MerkleRoot, calculatedMerkleRoot)
+			header.MerkleRoot, calcMerkleRoot)
 		return ruleError(ErrBadMerkleRoot, str)
 	}
 

integration/rpctest/blockgen.go

@@ -12,12 +12,12 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/mining"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcd/btcutil"
 )
 
 // solveBlock attempts to find a nonce which makes the passed block header hash
@@ -197,12 +197,12 @@ func CreateBlock(prevBlock *btcutil.Block, inclusionTxs []*btcutil.Tx,
 		_ = mining.AddWitnessCommitment(coinbaseTx, blockTxns)
 	}
 
-	merkles := blockchain.BuildMerkleTreeStore(blockTxns, false)
+	merkleRoot := blockchain.CalcMerkleRoot(blockTxns, false)
 	var block wire.MsgBlock
 	block.Header = wire.BlockHeader{
 		Version:    blockVersion,
 		PrevBlock:  *prevHash,
-		MerkleRoot: *merkles[len(merkles)-1],
+		MerkleRoot: merkleRoot,
 		Timestamp:  ts,
 		Bits:       net.PowLimitBits,
 	}

mining/mining.go

@@ -11,11 +11,11 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcd/btcutil"
 )
 
 const (
@@ -420,26 +420,26 @@ func NewBlkTmplGenerator(policy *Policy, params *chaincfg.Params,
 //
 // Given the above, a block generated by this function is of the following form:
 //
-//   -----------------------------------  --  --
-//  |      Coinbase Transaction         |   |   |
-//  |-----------------------------------|   |   |
-//  |                                   |   |   | ----- policy.BlockPrioritySize
-//  |   High-priority Transactions      |   |   |
-//  |                                   |   |   |
-//  |-----------------------------------|   | --
-//  |                                   |   |
-//  |                                   |   |
-//  |                                   |   |--- policy.BlockMaxSize
-//  |  Transactions prioritized by fee  |   |
-//  |  until <= policy.TxMinFreeFee     |   |
-//  |                                   |   |
-//  |                                   |   |
-//  |                                   |   |
-//  |-----------------------------------|   |
-//  |  Low-fee/Non high-priority (free) |   |
-//  |  transactions (while block size   |   |
-//  |  <= policy.BlockMinSize)          |   |
-//   -----------------------------------  --
+//	 -----------------------------------  --  --
+//	|      Coinbase Transaction         |   |   |
+//	|-----------------------------------|   |   |
+//	|                                   |   |   | ----- policy.BlockPrioritySize
+//	|   High-priority Transactions      |   |   |
+//	|                                   |   |   |
+//	|-----------------------------------|   | --
+//	|                                   |   |
+//	|                                   |   |
+//	|                                   |   |--- policy.BlockMaxSize
+//	|  Transactions prioritized by fee  |   |
+//	|  until <= policy.TxMinFreeFee     |   |
+//	|                                   |   |
+//	|                                   |   |
+//	|                                   |   |
+//	|-----------------------------------|   |
+//	|  Low-fee/Non high-priority (free) |   |
+//	|  transactions (while block size   |   |
+//	|  <= policy.BlockMinSize)          |   |
+//	 -----------------------------------  --
 func (g *BlkTmplGenerator) NewBlockTemplate(payToAddress btcutil.Address) (*BlockTemplate, error) {
 	// Extend the most recently known best block.
 	best := g.chain.BestSnapshot()
@@ -804,6 +804,38 @@ mempoolLoop:
 	var witnessCommitment []byte
 	if witnessIncluded {
 		witnessCommitment = AddWitnessCommitment(coinbaseTx, blockTxns)
+		// The witness of the coinbase transaction MUST be exactly 32-bytes
+		// of all zeroes.
+		var witnessNonce [blockchain.CoinbaseWitnessDataLen]byte
+		coinbaseTx.MsgTx().TxIn[0].Witness = wire.TxWitness{witnessNonce[:]}
+
+		// Next, obtain the merkle root of a tree which consists of the
+		// wtxid of all transactions in the block. The coinbase
+		// transaction will have a special wtxid of all zeroes.
+		witnessMerkleRoot := blockchain.CalcMerkleRoot(blockTxns, true)
+
+		// The preimage to the witness commitment is:
+		// witnessRoot || coinbaseWitness
+		var witnessPreimage [64]byte
+		copy(witnessPreimage[:32], witnessMerkleRoot[:])
+		copy(witnessPreimage[32:], witnessNonce[:])
+
+		// The witness commitment itself is the double-sha256 of the
+		// witness preimage generated above. With the commitment
+		// generated, the witness script for the output is: OP_RETURN
+		// OP_DATA_36 {0xaa21a9ed || witnessCommitment}. The leading
+		// prefix is referred to as the "witness magic bytes".
+		witnessCommitment = chainhash.DoubleHashB(witnessPreimage[:])
+		witnessScript := append(blockchain.WitnessMagicBytes, witnessCommitment...)
+
+		// Finally, create the OP_RETURN carrying witness commitment
+		// output as an additional output within the coinbase.
+		commitmentOutput := &wire.TxOut{
+			Value:    0,
+			PkScript: witnessScript,
+		}
+		coinbaseTx.MsgTx().TxOut = append(coinbaseTx.MsgTx().TxOut,
+			commitmentOutput)
 	}
 
 	// Calculate the required difficulty for the block.  The timestamp
@@ -823,12 +855,11 @@ mempoolLoop:
 	}
 
 	// Create a new block ready to be solved.
-	merkles := blockchain.BuildMerkleTreeStore(blockTxns, false)
 	var msgBlock wire.MsgBlock
 	msgBlock.Header = wire.BlockHeader{
 		Version:    nextBlockVersion,
 		PrevBlock:  best.Hash,
-		MerkleRoot: *merkles[len(merkles)-1],
+		MerkleRoot: blockchain.CalcMerkleRoot(blockTxns, false),
 		Timestamp:  ts,
 		Bits:       reqDifficulty,
 	}
@@ -953,8 +984,8 @@ func (g *BlkTmplGenerator) UpdateExtraNonce(msgBlock *wire.MsgBlock, blockHeight
 
 	// Recalculate the merkle root with the updated extra nonce.
 	block := btcutil.NewBlock(msgBlock)
-	merkles := blockchain.BuildMerkleTreeStore(block.Transactions(), false)
-	msgBlock.Header.MerkleRoot = *merkles[len(merkles)-1]
+	merkleRoot := blockchain.CalcMerkleRoot(block.Transactions(), false)
+	msgBlock.Header.MerkleRoot = merkleRoot
 	return nil
 }
 

rpcserver.go

@@ -1651,8 +1651,8 @@ func (state *gbtWorkState) updateBlockTemplate(s *rpcServer, useCoinbaseValue bo
 
 			// Update the merkle root.
 			block := btcutil.NewBlock(template.Block)
-			merkles := blockchain.BuildMerkleTreeStore(block.Transactions(), false)
-			template.Block.Header.MerkleRoot = *merkles[len(merkles)-1]
+			merkleRoot := blockchain.CalcMerkleRoot(block.Transactions(), false)
+			template.Block.Header.MerkleRoot = merkleRoot
 		}
 
 		// Set locals for convenience.