Method PackageRBFChecks

src/validation.cpp:1041–1137

}

bool MemPoolAccept::PackageRBFChecks(const std::vector<CTransactionRef>& txns,
                                     std::vector<Workspace>& workspaces,
                                     const int64_t total_vsize,
                                     PackageValidationState& package_state)
{
    AssertLockHeld(cs_main);
    AssertLockHeld(m_pool.cs);

    assert(std::all_of(txns.cbegin(), txns.cend(), [this](const auto& tx)
                       { return !m_pool.exists(tx->GetHash());}));

    assert(txns.size() == workspaces.size());

    // We're in package RBF context; replacement proposal must be size 2
    if (workspaces.size() != 2 || !Assume(IsChildWithParents(txns))) {
        return package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package RBF failed: package must be 1-parent-1-child");
    }

    // If the package has in-mempool parents, we won't consider a package RBF
    // since it would result in a cluster larger than 2.
    // N.B. To relax this constraint we will need to revisit how CCoinsViewMemPool::PackageAddTransaction
    // is being used inside AcceptMultipleTransactions to track available inputs while processing a package.
    // Specifically we would need to check that the ancestors of the new
    // transactions don't intersect with the set of transactions to be removed
    // due to RBF, which is not checked at all in the package acceptance
    // context.
    for (const auto& ws : workspaces) {
        if (!ws.m_parents.empty()) {
            return package_state.Invalid(PackageValidationResult::PCKG_POLICY, "package RBF failed: new transaction cannot have mempool ancestors");
        }
    }

    // Aggregate all conflicts into one set.
    CTxMemPool::setEntries direct_conflict_iters;
    for (Workspace& ws : workspaces) {
        // Aggregate all conflicts into one set.
        direct_conflict_iters.merge(ws.m_iters_conflicting);
    }

    const auto& parent_ws = workspaces[0];
    const auto& child_ws = workspaces[1];

    // Don't consider replacements that would cause us to remove a large number of mempool entries.
    // This limit is not increased in a package RBF. Use the aggregate number of transactions.
    CTxMemPool::setEntries all_conflicts;
    if (const auto err_string{GetEntriesForConflicts(*child_ws.m_ptx, m_pool, direct_conflict_iters,
                                                     all_conflicts)}) {
        return package_state.Invalid(PackageValidationResult::PCKG_POLICY,
                                     "package RBF failed: too many potential replacements", *err_string);
    }

    for (CTxMemPool::txiter it : all_conflicts) {
        m_subpackage.m_changeset->StageRemoval(it);
        m_subpackage.m_conflicting_fees += it->GetModifiedFee();
        m_subpackage.m_conflicting_size += it->GetTxSize();
    }

    // Use the child as the transaction for attributing errors to.