// TestHasCanonicalPush ensures the canonicalPush function works as expected.
func TestHasCanonicalPush(t *testing.T) {
t.Parallel()
for i := 0; i < 65535; i++ {
builder := txscript.NewScriptBuilder()
builder.AddInt64(int64(i))
script, err := builder.Script()
if err != nil {
t.Errorf("Script: test #%d unexpected error: %v\n", i,
err)
continue
}
if result := txscript.IsPushOnlyScript(script); !result {
t.Errorf("IsPushOnlyScript: test #%d failed: %x\n", i,
script)
continue
}
pops, err := txscript.TstParseScript(script)
if err != nil {
t.Errorf("TstParseScript: #%d failed: %v", i, err)
continue
}
for _, pop := range pops {
if result := txscript.TstHasCanonicalPushes(pop); !result {
t.Errorf("TstHasCanonicalPushes: test #%d "+
"failed: %x\n", i, script)
break
}
}
}
for i := 0; i <= txscript.MaxScriptElementSize; i++ {
builder := txscript.NewScriptBuilder()
builder.AddData(bytes.Repeat([]byte{0x49}, i))
script, err := builder.Script()
if err != nil {
t.Errorf("StandardPushesTests test #%d unexpected error: %v\n", i, err)
continue
}
if result := txscript.IsPushOnlyScript(script); !result {
t.Errorf("StandardPushesTests IsPushOnlyScript test #%d failed: %x\n", i, script)
continue
}
pops, err := txscript.TstParseScript(script)
if err != nil {
t.Errorf("StandardPushesTests #%d failed to TstParseScript: %v", i, err)
continue
}
for _, pop := range pops {
if result := txscript.TstHasCanonicalPushes(pop); !result {
t.Errorf("StandardPushesTests TstHasCanonicalPushes test #%d failed: %x\n", i, script)
break
}
}
}
}
// TestExceedMaxScriptSize ensures that all of the functions that can be used
// to add data to a script don't allow the script to exceed the max allowed
// size.
func TestExceedMaxScriptSize(t *testing.T) {
t.Parallel()
// Start off by constructing a max size script.
maxScriptSize := txscript.TstMaxScriptSize
builder := txscript.NewScriptBuilder()
builder.Reset().AddFullData(make([]byte, maxScriptSize-3))
origScript, err := builder.Script()
if err != nil {
t.Fatalf("Unexpected error for max size script: %v", err)
}
// Ensure adding data that would exceed the maximum size of the script
// does not add the data.
script, err := builder.AddData([]byte{0x00}).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatalf("ScriptBuilder.AddData allowed exceeding max script "+
"size: %v", len(script))
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddData unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
// Ensure adding an opcode that would exceed the maximum size of the
// script does not add the data.
builder.Reset().AddFullData(make([]byte, maxScriptSize-3))
script, err = builder.AddOp(txscript.OP_0).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatalf("ScriptBuilder.AddOp unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddOp unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
// Ensure adding an integer that would exceed the maximum size of the
// script does not add the data.
builder.Reset().AddFullData(make([]byte, maxScriptSize-3))
script, err = builder.AddInt64(0).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatalf("ScriptBuilder.AddInt64 unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddInt64 unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
}
// TestScriptBuilderAddOp tests that pushing opcodes to a script via the
// ScriptBuilder API works as expected.
func TestScriptBuilderAddOp(t *testing.T) {
t.Parallel()
tests := []struct {
name string
opcodes []byte
expected []byte
}{
{
name: "push OP_0",
opcodes: []byte{txscript.OP_0},
expected: []byte{txscript.OP_0},
},
{
name: "push OP_1 OP_2",
opcodes: []byte{txscript.OP_1, txscript.OP_2},
expected: []byte{txscript.OP_1, txscript.OP_2},
},
{
name: "push OP_HASH160 OP_EQUAL",
opcodes: []byte{txscript.OP_HASH160, txscript.OP_EQUAL},
expected: []byte{txscript.OP_HASH160, txscript.OP_EQUAL},
},
}
builder := txscript.NewScriptBuilder()
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
builder.Reset()
for _, opcode := range test.opcodes {
builder.AddOp(opcode)
}
result, err := builder.Script()
if err != nil {
t.Errorf("ScriptBuilder.AddOp #%d (%s) unexpected "+
"error: %v", i, test.name, err)
continue
}
if !bytes.Equal(result, test.expected) {
t.Errorf("ScriptBuilder.AddOp #%d (%s) wrong result\n"+
"got: %x\nwant: %x", i, test.name, result,
test.expected)
continue
}
}
}
// createCoinbaseTx returns a coinbase transaction paying an appropriate subsidy
// based on the passed block height to the provided address. When the address
// is nil, the coinbase transaction will instead be redeemable by anyone.
//
// See the comment for NewBlockTemplate for more information about why the nil
// address handling is useful.
func createCoinbaseTx(coinbaseScript []byte, nextBlockHeight int32, addr btcutil.Address) (*btcutil.Tx, error) {
// Create the script to pay to the provided payment address if one was
// specified. Otherwise create a script that allows the coinbase to be
// redeemable by anyone.
var pkScript []byte
if addr != nil {
var err error
pkScript, err = txscript.PayToAddrScript(addr)
if err != nil {
return nil, err
}
} else {
var err error
scriptBuilder := txscript.NewScriptBuilder()
pkScript, err = scriptBuilder.AddOp(txscript.OP_TRUE).Script()
if err != nil {
return nil, err
}
}
tx := wire.NewMsgTx()
tx.AddTxIn(&wire.TxIn{
// Coinbase transactions have no inputs, so previous outpoint is
// zero hash and max index.
PreviousOutPoint: *wire.NewOutPoint(&wire.ShaHash{},
wire.MaxPrevOutIndex),
SignatureScript: coinbaseScript,
Sequence: wire.MaxTxInSequenceNum,
})
tx.AddTxOut(&wire.TxOut{
Value: blockchain.CalcBlockSubsidy(nextBlockHeight,
activeNetParams.Params),
PkScript: pkScript,
})
return btcutil.NewTx(tx), nil
}
// TestScriptBuilderAddInt64 tests that pushing signed integers to a script via
// the ScriptBuilder API works as expected.
func TestScriptBuilderAddInt64(t *testing.T) {
t.Parallel()
tests := []struct {
name string
val int64
expected []byte
}{
{name: "push -1", val: -1, expected: []byte{txscript.OP_1NEGATE}},
{name: "push small int 0", val: 0, expected: []byte{txscript.OP_0}},
{name: "push small int 1", val: 1, expected: []byte{txscript.OP_1}},
{name: "push small int 2", val: 2, expected: []byte{txscript.OP_2}},
{name: "push small int 3", val: 3, expected: []byte{txscript.OP_3}},
{name: "push small int 4", val: 4, expected: []byte{txscript.OP_4}},
{name: "push small int 5", val: 5, expected: []byte{txscript.OP_5}},
{name: "push small int 6", val: 6, expected: []byte{txscript.OP_6}},
{name: "push small int 7", val: 7, expected: []byte{txscript.OP_7}},
{name: "push small int 8", val: 8, expected: []byte{txscript.OP_8}},
{name: "push small int 9", val: 9, expected: []byte{txscript.OP_9}},
{name: "push small int 10", val: 10, expected: []byte{txscript.OP_10}},
{name: "push small int 11", val: 11, expected: []byte{txscript.OP_11}},
{name: "push small int 12", val: 12, expected: []byte{txscript.OP_12}},
{name: "push small int 13", val: 13, expected: []byte{txscript.OP_13}},
{name: "push small int 14", val: 14, expected: []byte{txscript.OP_14}},
{name: "push small int 15", val: 15, expected: []byte{txscript.OP_15}},
{name: "push small int 16", val: 16, expected: []byte{txscript.OP_16}},
{name: "push 17", val: 17, expected: []byte{txscript.OP_DATA_1, 0x11}},
{name: "push 65", val: 65, expected: []byte{txscript.OP_DATA_1, 0x41}},
{name: "push 127", val: 127, expected: []byte{txscript.OP_DATA_1, 0x7f}},
{name: "push 128", val: 128, expected: []byte{txscript.OP_DATA_2, 0x80, 0}},
{name: "push 255", val: 255, expected: []byte{txscript.OP_DATA_2, 0xff, 0}},
{name: "push 256", val: 256, expected: []byte{txscript.OP_DATA_2, 0, 0x01}},
{name: "push 32767", val: 32767, expected: []byte{txscript.OP_DATA_2, 0xff, 0x7f}},
{name: "push 32768", val: 32768, expected: []byte{txscript.OP_DATA_3, 0, 0x80, 0}},
{name: "push -2", val: -2, expected: []byte{txscript.OP_DATA_1, 0x82}},
{name: "push -3", val: -3, expected: []byte{txscript.OP_DATA_1, 0x83}},
{name: "push -4", val: -4, expected: []byte{txscript.OP_DATA_1, 0x84}},
{name: "push -5", val: -5, expected: []byte{txscript.OP_DATA_1, 0x85}},
{name: "push -17", val: -17, expected: []byte{txscript.OP_DATA_1, 0x91}},
{name: "push -65", val: -65, expected: []byte{txscript.OP_DATA_1, 0xc1}},
{name: "push -127", val: -127, expected: []byte{txscript.OP_DATA_1, 0xff}},
{name: "push -128", val: -128, expected: []byte{txscript.OP_DATA_2, 0x80, 0x80}},
{name: "push -255", val: -255, expected: []byte{txscript.OP_DATA_2, 0xff, 0x80}},
{name: "push -256", val: -256, expected: []byte{txscript.OP_DATA_2, 0x00, 0x81}},
{name: "push -32767", val: -32767, expected: []byte{txscript.OP_DATA_2, 0xff, 0xff}},
{name: "push -32768", val: -32768, expected: []byte{txscript.OP_DATA_3, 0x00, 0x80, 0x80}},
}
builder := txscript.NewScriptBuilder()
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
builder.Reset().AddInt64(test.val)
result, err := builder.Script()
if err != nil {
t.Errorf("ScriptBuilder.AddInt64 #%d (%s) unexpected "+
"error: %v", i, test.name, err)
continue
}
if !bytes.Equal(result, test.expected) {
t.Errorf("ScriptBuilder.AddInt64 #%d (%s) wrong result\n"+
"got: %x\nwant: %x", i, test.name, result,
test.expected)
continue
}
}
}
// TestErroredScript ensures that all of the functions that can be used to add
// data to a script don't modify the script once an error has happened.
func TestErroredScript(t *testing.T) {
t.Parallel()
// Start off by constructing a near max size script that has enough
// space left to add each data type without an error and force an
// initial error condition.
maxScriptSize := txscript.TstMaxScriptSize
builder := txscript.NewScriptBuilder()
builder.Reset().AddFullData(make([]byte, maxScriptSize-8))
origScript, err := builder.Script()
if err != nil {
t.Fatalf("ScriptBuilder.AddFullData unexpected error: %v", err)
}
script, err := builder.AddData([]byte{0x00, 0x00, 0x00, 0x00, 0x00}).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatalf("ScriptBuilder.AddData allowed exceeding max script "+
"size: %v", len(script))
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddData unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
// Ensure adding data, even using the non-canonical path, to a script
// that has errored doesn't succeed.
script, err = builder.AddFullData([]byte{0x00}).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatal("ScriptBuilder.AddFullData succeeded on errored script")
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddFullData unexpected modified "+
"script - got len %d, want len %d", len(script),
len(origScript))
}
// Ensure adding data to a script that has errored doesn't succeed.
script, err = builder.AddData([]byte{0x00}).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatal("ScriptBuilder.AddData succeeded on errored script")
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddData unexpected modified "+
"script - got len %d, want len %d", len(script),
len(origScript))
}
// Ensure adding an opcode to a script that has errored doesn't succeed.
script, err = builder.AddOp(txscript.OP_0).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatal("ScriptBuilder.AddOp succeeded on errored script")
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddOp unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
// Ensure adding an integer to a script that has errored doesn't
// succeed.
script, err = builder.AddInt64(0).Script()
if _, ok := err.(txscript.ErrScriptNotCanonical); !ok || err == nil {
t.Fatal("ScriptBuilder.AddInt64 succeeded on errored script")
}
if !bytes.Equal(script, origScript) {
t.Fatalf("ScriptBuilder.AddInt64 unexpected modified script - "+
"got len %d, want len %d", len(script), len(origScript))
}
// Ensure the error has a message set.
if err.Error() == "" {
t.Fatal("ErrScriptNotCanonical.Error does not have any text")
}
}
// TestScriptBuilderAddData tests that pushing data to a script via the
// ScriptBuilder API works as expected and conforms to BIP0062.
func TestScriptBuilderAddData(t *testing.T) {
t.Parallel()
tests := []struct {
name string
data []byte
expected []byte
useFull bool // use AddFullData instead of AddData.
}{
// BIP0062: Pushing an empty byte sequence must use OP_0.
{name: "push empty byte sequence", data: nil, expected: []byte{txscript.OP_0}},
{name: "push 1 byte 0x00", data: []byte{0x00}, expected: []byte{txscript.OP_0}},
// BIP0062: Pushing a 1-byte sequence of byte 0x01 through 0x10 must use OP_n.
{name: "push 1 byte 0x01", data: []byte{0x01}, expected: []byte{txscript.OP_1}},
{name: "push 1 byte 0x02", data: []byte{0x02}, expected: []byte{txscript.OP_2}},
{name: "push 1 byte 0x03", data: []byte{0x03}, expected: []byte{txscript.OP_3}},
{name: "push 1 byte 0x04", data: []byte{0x04}, expected: []byte{txscript.OP_4}},
{name: "push 1 byte 0x05", data: []byte{0x05}, expected: []byte{txscript.OP_5}},
{name: "push 1 byte 0x06", data: []byte{0x06}, expected: []byte{txscript.OP_6}},
{name: "push 1 byte 0x07", data: []byte{0x07}, expected: []byte{txscript.OP_7}},
{name: "push 1 byte 0x08", data: []byte{0x08}, expected: []byte{txscript.OP_8}},
{name: "push 1 byte 0x09", data: []byte{0x09}, expected: []byte{txscript.OP_9}},
{name: "push 1 byte 0x0a", data: []byte{0x0a}, expected: []byte{txscript.OP_10}},
{name: "push 1 byte 0x0b", data: []byte{0x0b}, expected: []byte{txscript.OP_11}},
{name: "push 1 byte 0x0c", data: []byte{0x0c}, expected: []byte{txscript.OP_12}},
{name: "push 1 byte 0x0d", data: []byte{0x0d}, expected: []byte{txscript.OP_13}},
{name: "push 1 byte 0x0e", data: []byte{0x0e}, expected: []byte{txscript.OP_14}},
{name: "push 1 byte 0x0f", data: []byte{0x0f}, expected: []byte{txscript.OP_15}},
{name: "push 1 byte 0x10", data: []byte{0x10}, expected: []byte{txscript.OP_16}},
// BIP0062: Pushing the byte 0x81 must use OP_1NEGATE.
{name: "push 1 byte 0x81", data: []byte{0x81}, expected: []byte{txscript.OP_1NEGATE}},
// BIP0062: Pushing any other byte sequence up to 75 bytes must
// use the normal data push (opcode byte n, with n the number of
// bytes, followed n bytes of data being pushed).
{name: "push 1 byte 0x11", data: []byte{0x11}, expected: []byte{txscript.OP_DATA_1, 0x11}},
{name: "push 1 byte 0x80", data: []byte{0x80}, expected: []byte{txscript.OP_DATA_1, 0x80}},
{name: "push 1 byte 0x82", data: []byte{0x82}, expected: []byte{txscript.OP_DATA_1, 0x82}},
{name: "push 1 byte 0xff", data: []byte{0xff}, expected: []byte{txscript.OP_DATA_1, 0xff}},
{
name: "push data len 17",
data: bytes.Repeat([]byte{0x49}, 17),
expected: append([]byte{txscript.OP_DATA_17}, bytes.Repeat([]byte{0x49}, 17)...),
},
{
name: "push data len 75",
data: bytes.Repeat([]byte{0x49}, 75),
expected: append([]byte{txscript.OP_DATA_75}, bytes.Repeat([]byte{0x49}, 75)...),
},
// BIP0062: Pushing 76 to 255 bytes must use OP_PUSHDATA1.
{
name: "push data len 76",
data: bytes.Repeat([]byte{0x49}, 76),
expected: append([]byte{txscript.OP_PUSHDATA1, 76}, bytes.Repeat([]byte{0x49}, 76)...),
},
{
name: "push data len 255",
data: bytes.Repeat([]byte{0x49}, 255),
expected: append([]byte{txscript.OP_PUSHDATA1, 255}, bytes.Repeat([]byte{0x49}, 255)...),
},
// BIP0062: Pushing 256 to 520 bytes must use OP_PUSHDATA2.
{
name: "push data len 256",
data: bytes.Repeat([]byte{0x49}, 256),
expected: append([]byte{txscript.OP_PUSHDATA2, 0, 1}, bytes.Repeat([]byte{0x49}, 256)...),
},
{
name: "push data len 520",
data: bytes.Repeat([]byte{0x49}, 520),
expected: append([]byte{txscript.OP_PUSHDATA2, 0x08, 0x02}, bytes.Repeat([]byte{0x49}, 520)...),
},
// BIP0062: OP_PUSHDATA4 can never be used, as pushes over 520
// bytes are not allowed, and those below can be done using
// other operators.
{
name: "push data len 521",
data: bytes.Repeat([]byte{0x49}, 521),
expected: nil,
},
{
name: "push data len 32767 (canonical)",
data: bytes.Repeat([]byte{0x49}, 32767),
expected: nil,
},
{
name: "push data len 65536 (canonical)",
data: bytes.Repeat([]byte{0x49}, 65536),
expected: nil,
},
// Additional tests for the PushFullData function that
// intentionally allows data pushes to exceed the limit for
// regression testing purposes.
// 3-byte data push via OP_PUSHDATA_2.
{
name: "push data len 32767 (non-canonical)",
data: bytes.Repeat([]byte{0x49}, 32767),
expected: append([]byte{txscript.OP_PUSHDATA2, 255, 127}, bytes.Repeat([]byte{0x49}, 32767)...),
useFull: true,
},
// 5-byte data push via OP_PUSHDATA_4.
{
name: "push data len 65536 (non-canonical)",
data: bytes.Repeat([]byte{0x49}, 65536),
expected: append([]byte{txscript.OP_PUSHDATA4, 0, 0, 1, 0}, bytes.Repeat([]byte{0x49}, 65536)...),
useFull: true,
},
}
builder := txscript.NewScriptBuilder()
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
if !test.useFull {
builder.Reset().AddData(test.data)
} else {
builder.Reset().AddFullData(test.data)
}
result, _ := builder.Script()
if !bytes.Equal(result, test.expected) {
t.Errorf("ScriptBuilder.AddData #%d (%s) wrong result\n"+
"got: %x\nwant: %x", i, test.name, result,
test.expected)
continue
}
}
}
// TestCheckPkScriptStandard tests the checkPkScriptStandard API.
func TestCheckPkScriptStandard(t *testing.T) {
var pubKeys [][]byte
for i := 0; i < 4; i++ {
pk, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
t.Fatalf("TestCheckPkScriptStandard NewPrivateKey failed: %v",
err)
return
}
pubKeys = append(pubKeys, pk.PubKey().SerializeCompressed())
}
tests := []struct {
name string // test description.
script *txscript.ScriptBuilder
isStandard bool
}{
{
"key1 and key2",
txscript.NewScriptBuilder().AddOp(txscript.OP_2).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
true,
},
{
"key1 or key2",
txscript.NewScriptBuilder().AddOp(txscript.OP_1).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
true,
},
{
"escrow",
txscript.NewScriptBuilder().AddOp(txscript.OP_2).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddData(pubKeys[2]).
AddOp(txscript.OP_3).AddOp(txscript.OP_CHECKMULTISIG),
true,
},
{
"one of four",
txscript.NewScriptBuilder().AddOp(txscript.OP_1).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddData(pubKeys[2]).AddData(pubKeys[3]).
AddOp(txscript.OP_4).AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed1",
txscript.NewScriptBuilder().AddOp(txscript.OP_3).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed2",
txscript.NewScriptBuilder().AddOp(txscript.OP_2).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_3).AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed3",
txscript.NewScriptBuilder().AddOp(txscript.OP_0).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_2).AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed4",
txscript.NewScriptBuilder().AddOp(txscript.OP_1).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_0).AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed5",
txscript.NewScriptBuilder().AddOp(txscript.OP_1).
AddData(pubKeys[0]).AddData(pubKeys[1]).
AddOp(txscript.OP_CHECKMULTISIG),
false,
},
{
"malformed6",
txscript.NewScriptBuilder().AddOp(txscript.OP_1).
AddData(pubKeys[0]).AddData(pubKeys[1]),
false,
},
}
for _, test := range tests {
script, err := test.script.Script()
if err != nil {
t.Fatalf("TestCheckPkScriptStandard test '%s' "+
"failed: %v", test.name, err)
continue
}
scriptClass := txscript.GetScriptClass(script)
got := checkPkScriptStandard(script, scriptClass)
if (test.isStandard && got != nil) ||
(!test.isStandard && got == nil) {
t.Fatalf("TestCheckPkScriptStandard test '%s' failed",
test.name)
return
}
}
}
// standardCoinbaseScript returns a standard script suitable for use as the
// signature script of the coinbase transaction of a new block. In particular,
// it starts with the block height that is required by version 2 blocks and adds
// the extra nonce as well as additional coinbase flags.
func standardCoinbaseScript(nextBlockHeight int32, extraNonce uint64) ([]byte, error) {
return txscript.NewScriptBuilder().AddInt64(int64(nextBlockHeight)).
AddInt64(int64(extraNonce)).AddData([]byte(coinbaseFlags)).
Script()
}