txscript: add some txscript support for parsing taproot scripts

txscript/standard.go

@@ -1001,6 +1001,15 @@ func ExtractPkScriptAddrs(pkScript []byte,
 		return WitnessV0ScriptHashTy, addrs, 1, nil
 	}
 
+	if hash := extractWitnessV1ScriptHash(pkScript); hash != nil {
+		var addrs []btcutil.Address
+		addr, err := btcutil.NewAddressTaproot(hash, chainParams)
+		if err == nil {
+			addrs = append(addrs, addr)
+		}
+		return WitnessV1TaprootTy, addrs, 1, nil
+	}
+
 	// If none of the above passed, then the address must be non-standard.
 	return NonStandardTy, nil, 0, nil
 }

txscript/standard_test.go

@@ -11,9 +11,9 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcd/btcutil"
 )
 
 // mustParseShortForm parses the passed short form script and returns the
@@ -71,6 +71,20 @@ func newAddressScriptHash(scriptHash []byte) btcutil.Address {
 	return addr
 }
 
+// newAddressTaproot returns a new btcutil.AddressTaproot from the
+// provided hash.  It panics if an error occurs.  This is only used in the tests
+// as a helper since the only way it can fail is if there is an error in the
+// test source code.
+func newAddressTaproot(scriptHash []byte) btcutil.Address {
+	addr, err := btcutil.NewAddressTaproot(scriptHash,
+		&chaincfg.MainNetParams)
+	if err != nil {
+		panic("invalid script hash in test source")
+	}
+
+	return addr
+}
+
 // TestExtractPkScriptAddrs ensures that extracting the type, addresses, and
 // number of required signatures from PkScripts works as intended.
 func TestExtractPkScriptAddrs(t *testing.T) {
@@ -311,8 +325,16 @@ func TestExtractPkScriptAddrs(t *testing.T) {
 			reqSigs: 1,
 			class:   MultiSigTy,
 		},
-		// from real tx: 691dd277dc0e90a462a3d652a1171686de49cf19067cd33c7df0392833fb986a, vout 44
-		// invalid public keys
+		{
+			name: "v1 p2tr witness-script-hash",
+			script: hexToBytes("51201a82f7457a9ba6ab1074e9f50" +
+				"053eefc637f8b046e389b636766bdc7d1f676f8"),
+			addrs: []btcutil.Address{newAddressTaproot(
+				hexToBytes("1a82f7457a9ba6ab1074e9f50053eefc6" +
+					"37f8b046e389b636766bdc7d1f676f8"))},
+			reqSigs: 1,
+			class:   WitnessV1TaprootTy,
+		},
 		{
 			name: "1 of 3 multisig with invalid pubkeys 2",
 			script: hexToBytes("514134633365633235396337346461636" +