BIP141 adds a new rule called "witness commitment". The document says: "The commitment is recorded in a scriptPubKey of the coinbase transaction." I didn't quite understand what that meant, Therefore, I directly placed the 'default_witness_commitment' provided by the block template in the scriptPubKey location when creating coinbase. Here's my code：
def makeCoinbase()->None:
global coinbase,tmpl
version=pack('<L',1)
inputCount=unhexlify('01')
txHash=unhexlify('0000000000000000000000000000000000000000000000000000000000000000')
preSequence=unhexlify('ffffffff')
eh=encodeHeight(tmpl['height']) #Don't worry about this function, it handles height
msg=eh+b'my message'
msgSize=pack('B',len(msg))
sequence=unhexlify('ffffffff')
outCount=unhexlify('01')
amount=pack('<Q',tmpl['coinbasevalue'])
script=unhexlify(tmpl['default_witness_commitment'])
scriptSize=pack('B',len(script))
lockTime=unhexlify('00000000')
coinbase=version+inputCount+txHash+preSequence+msgSize+msg+\
sequence+outCount+amount+scriptSize+script+lockTime
tmpl['transactions'].insert(0,{
'data':coinbase.hex(),
'txid':dblsha(coinbase)[::-1].hex()
})
The variable tmpl is the template obtained using the "getblocktemplate" command.I'm testing my code in regtest. When I submit a block, Bitcoin Core does create a new block. And my balance did go up. However, when I checked coinbases in the newly generated block, the result was as follows:
{
'txid': '9cb794f3292d1ece3af6c1d3055cf6fb26cf2126ff48b39b229bfec5ec651ec4',
'hash': 'de081b2a9552ac559d3501ed0669f675530fe9890e27d263c1aff65e678ddc4e',
'version': 1,
'size': 153,
'vsize': 126,
'weight': 504,
'locktime': 0,
'vin': [{
'coinbase': '016c54686520477265617420476f642050616e',
'txinwitness': ['0000000000000000000000000000000000000000000000000000000000000000'],
'sequence': 4294967295}],
'vout': [{
'value': Decimal('50.00063100'),
'n': 0,
'scriptPubKey': {
'asm': 'OP_RETURN aa21a9edb14717ddf39dacad0babfff4d8d951c076e95d11d2b1f328632c32f98c015d2c',
'desc': 'raw(6a24aa21a9edb14717ddf39dacad0babfff4d8d951c076e95d11d2b1f328632c32f98c015d2c)#psf60z3m',
'hex': '6a24aa21a9edb14717ddf39dacad0babfff4d8d951c076e95d11d2b1f328632c32f98c015d2c',
'type': 'nulldata'
}
}],
'hex': '010000000001010000000000000000000000000000000000000000000000000000000000000000ffffffff13016c54686520477265617420476f642050616effffffff017ce8062a01000000266a24aa21a9edb14717ddf39dacad0babfff4d8d951c076e95d11d2b1f328632c32f98c015d2c0120000000000000000000000000000000000000000000000000000000000000000000000000'
}
As you can see, it contains only one vout. And that vout does not contain address. But I look at coinbase for blocks in the main network, and it always contains more than one vout, and the vout contains the address.My question is am I building coinbase the right way? If not, how do I fix it? Although the Bitcoin core did not report errors, I always suspected that I had lost the miner's address.
