Function ContextualCheckBlock

src/validation.cpp:3849–3942

NOTE: This function is not currently invoked by ConnectBlock(), so we * should consider upgrade issues if we change which consensus rules are * enforced in this function (eg by adding a new consensus rule). See comment * in ConnectBlock(). * Note that -reindex-chainstate skips the validation that happens here! */

 *  Note that -reindex-chainstate skips the validation that happens here!
 */
static bool ContextualCheckBlock(const CBlock& block, BlockValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
{
    const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;

    // Enforce BIP113 (Median Time Past).
    int nLockTimeFlags = 0;
    if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV)) {
        assert(pindexPrev != nullptr);
        nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
    }

    int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
                              ? pindexPrev->GetMedianTimePast()
                              : block.GetBlockTime();

    // Check that all transactions are finalized
    for (const auto& tx : block.vtx) {
        if (!IsFinalTx(*tx, nHeight, nLockTimeCutoff)) {
            return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-txns-nonfinal", "non-final transaction");
        }
    }

    // Enforce rule that the coinbase starts with serialized block height
    if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_HEIGHTINCB))
    {
        CScript expect = CScript() << nHeight;
        if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() ||
            !std::equal(expect.begin(), expect.end(), block.vtx[0]->vin[0].scriptSig.begin())) {
            return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "bad-cb-height", "block height mismatch in coinbase");
        }
    }

    // Coinbase transaction can not have input witness data which is not covered
    // (or committed to) by the witness or regular merkle tree
    for (const auto& inwit : block.vtx[0]->witness.vtxinwit) {
        if (!inwit.vchIssuanceAmountRangeproof.empty() ||
                !inwit.vchInflationKeysRangeproof.empty() ||
                !inwit.m_pegin_witness.IsNull()) {
            return state.Invalid(BlockValidationResult::BLOCK_MUTATED, "bad-cb-witness", "Coinbase has invalid input witness data.");
        }
    }

    // Validation for witness commitments.
    // * We compute the witness hash (which is the hash including witnesses) of all the block's transactions, except the
    //   coinbase (where 0x0000....0000 is used instead).
    // * The coinbase scriptWitness is a stack of a single 32-byte vector, containing a witness reserved value (unconstrained).
    // * We build a merkle tree with all those witness hashes as leaves (similar to the hashMerkleRoot in the block header).
    // * There must be at least one output whose scriptPubKey is a single 36-byte push, the first 4 bytes of which are
    //   {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness reserved value). In case there are
    //   multiple, the last one is used.
    bool fHaveWitness = false;
    if (DeploymentActiveAfter(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT)) {
        int commitpos = GetWitnessCommitmentIndex(block);
        if (commitpos != NO_WITNESS_COMMITMENT) {
            bool malleated = false;
            uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated);
            // The malleation check is ignored; as the transaction tree itself
            // already does not permit it, it is impossible to trigger in the