[0.18] getnewblockhex: Take data push for arbitrary data in block coinbase c…

src/miner.cpp

@@ -102,7 +102,7 @@ void BlockAssembler::resetBlock()
 Optional<int64_t> BlockAssembler::m_last_block_num_txs{nullopt};
 Optional<int64_t> BlockAssembler::m_last_block_weight{nullopt};
 
-std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& scriptPubKeyIn, int min_tx_age, DynaFedParamEntry* proposed_entry)
+std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& scriptPubKeyIn, int min_tx_age, DynaFedParamEntry* proposed_entry, CScript const* commit_script)
 {
  assert(min_tx_age >= 0);
  int64_t nTimeStart = GetTimeMicros();
@@ -195,6 +195,10 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
  }
  }
  coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
+ // Non-consensus commitment output before finishing coinbase transaction
+ if (commit_script) {
+ coinbaseTx.vout.insert(coinbaseTx.vout.begin(), CTxOut(policyAsset, 0, *commit_script));
+ }
  pblock->vtx[0] = MakeTransactionRef(std::move(coinbaseTx));
  pblocktemplate->vchCoinbaseCommitment = GenerateCoinbaseCommitment(*pblock, pindexPrev, chainparams.GetConsensus());
  pblocktemplate->vTxFees[0] = -nFees;

src/miner.h

@@ -159,7 +159,7 @@ class BlockAssembler
  BlockAssembler(const CChainParams& params, const Options& options);
 
  /** Construct a new block template with coinbase to scriptPubKeyIn. min_tx_age is in seconds */
- std::unique_ptr<CBlockTemplate> CreateNewBlock(const CScript& scriptPubKeyIn, int min_tx_age=0, DynaFedParamEntry* = nullptr);
+ std::unique_ptr<CBlockTemplate> CreateNewBlock(const CScript& scriptPubKeyIn, int min_tx_age=0, DynaFedParamEntry* = nullptr, CScript const* commit_script = nullptr);
 
  static Optional<int64_t> m_last_block_num_txs;
  static Optional<int64_t> m_last_block_weight;

src/rpc/mining.cpp

@@ -997,7 +997,7 @@ static UniValue estimaterawfee(const JSONRPCRequest& request)
 
 UniValue getnewblockhex(const JSONRPCRequest& request)
 {
- if (request.fHelp || request.params.size() > 2)
+ if (request.fHelp || request.params.size() > 3)
  throw std::runtime_error(
  RPCHelpMan{"getnewblockhex",
  "\nGets hex representation of a proposed, unmined new block\n",
@@ -1015,6 +1015,7 @@ UniValue getnewblockhex(const JSONRPCRequest& request)
  },
  },
  "proposed_parameters"},
+ {"commit_data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "Data in hex to be committed to in an additional coinbase output."},
  },
  RPCResult{
  "blockhex (hex) The block hex\n"
@@ -1069,9 +1070,17 @@ UniValue getnewblockhex(const JSONRPCRequest& request)
  proposed.m_serialize_type = 2;
  }
 
+ // Any commitment required for non-consensus reasons.
+ // This will be placed in the first coinbase output.
+ CScript data_commitment;
+ if (!request.params[2].isNull()) {
+ std::vector<unsigned char> data_bytes = ParseHex(request.params[2].get_str());
+ data_commitment = CScript() << OP_RETURN << data_bytes;
+ }
+
  CScript feeDestinationScript = Params().GetConsensus().mandatory_coinbase_destination;
  if (feeDestinationScript == CScript()) feeDestinationScript = CScript() << OP_TRUE;
- std::unique_ptr<CBlockTemplate> pblocktemplate(BlockAssembler(Params()).CreateNewBlock(feeDestinationScript, required_wait, &proposed));
+ std::unique_ptr<CBlockTemplate> pblocktemplate(BlockAssembler(Params()).CreateNewBlock(feeDestinationScript, required_wait, &proposed, data_commitment.empty() ? nullptr : &data_commitment));
  if (!pblocktemplate.get()) {
  throw JSONRPCError(RPC_INTERNAL_ERROR, "Wallet keypool empty");
  }
@@ -1472,7 +1481,7 @@ static const CRPCCommand commands[] =
  { "mining", "getblocktemplate", &getblocktemplate, {"template_request"} },
  { "generating", "combineblocksigs", &combineblocksigs, {"blockhex","signatures"} },
  { "mining", "submitheader", &submitheader, {"hexdata"} },
- { "generating", "getnewblockhex", &getnewblockhex, {"min_tx_age", "proposed_parameters"} },
+ { "generating", "getnewblockhex", &getnewblockhex, {"min_tx_age", "proposed_parameters", "commit_data"} },
  { "generating", "getcompactsketch", &getcompactsketch, {"block_hex"} },
  { "generating", "consumecompactsketch", &consumecompactsketch, {"sketch"} },
  { "generating", "consumegetblocktxn", &consumegetblocktxn, {"full_block", "block_tx_req"} },

test/functional/feature_blocksign.py

@@ -9,6 +9,13 @@
  address,
  key,
 )
+from test_framework.messages import (
+ FromHex,
+ CBlock,
+)
+from test_framework.script import (
+ CScript
+)
 
 # Generate wallet import format from private key.
 def wif(pk):
@@ -113,6 +120,14 @@ def mine_block(self, make_transactions):
  miner.sendtoaddress(miner_next.getnewaddress(), int(miner.getbalance()['bitcoin']/10), "", "", True)
  # miner makes a block
  block = miner.getnewblockhex()
+ block_struct = FromHex(CBlock(), block)
+
+ # make another block with the commitment field filled out
+ dummy_block = miner.getnewblockhex(commit_data="deadbeef")
+ dummy_struct = FromHex(CBlock(), dummy_block)
+ assert_equal(len(dummy_struct.vtx[0].vout), len(block_struct.vtx[0].vout) + 1)
+ # OP_RETURN deadbeef
+ assert_equal(CScript(dummy_struct.vtx[0].vout[0].scriptPubKey).hex(), '6a04deadbeef')
 
  # All nodes get compact blocks, first node may get complete
  # block in 0.5 RTT even with transactions thanks to p2p connection