Extract Mining Beneficiary from BlockHeader.getExtraData()

[DavePearce]

Linea uses the clique consensus protocol (see EIP-225). The upshot of this is that the mining beneficiary address is embedded in the data field of the block, whilst coinbase is set to 0x0. Therefore, this part of ReplayExecutionEnvironment is incorrect:

final TransactionProcessingResult outcome =
            transactionProcessor.processTransaction(
                updater,
                (ProcessableBlockHeader) header,
                tx,
                header.getCoinbase(),
               ...);

Specifically, header.getCoinbase() does not return the correct beneficiary address. Instead, we need to extract it from header.getExtraData().

This explains why various transactions fail with an incorrect balance for the address (see here for more).

[OlivierBBB]

Thanks @DavePearce. I discussed this point with @julien-marchand, too, and the conclusion was that blocks contain miner=0x000000 which is where we got the coinbase at 0x0 from in our tests. We have to use the address (deduced from the public key) that signed the block instead for both

• the output of the COINBASE opcode
• the recipient address of fees

[DavePearce]

Completed by #1222