Method AcceptPackage

src/validation.cpp:1628–1777

}

PackageMempoolAcceptResult MemPoolAccept::AcceptPackage(const Package& package, ATMPArgs& args)
{
    Assert(!package.empty());
    AssertLockHeld(cs_main);
    // Used if returning a PackageMempoolAcceptResult directly from this function.
    PackageValidationState package_state_quit_early;

    // There are two topologies we are able to handle through this function:
    // (1) A single transaction
    // (2) A child-with-parents package.
    // Check that the package is well-formed. If it isn't, we won't try to validate any of the
    // transactions and thus won't return any MempoolAcceptResults, just a package-wide error.

    // Context-free package checks.
    if (!IsWellFormedPackage(package, package_state_quit_early)) {
        return PackageMempoolAcceptResult(package_state_quit_early, {});
    }

    if (package.size() > 1 && !IsChildWithParents(package)) {
        // All transactions in the package must be a parent of the last transaction. This is just an
        // opportunity for us to fail fast on a context-free check without taking the mempool lock.
        package_state_quit_early.Invalid(PackageValidationResult::PCKG_POLICY, "package-not-child-with-parents");
        return PackageMempoolAcceptResult(package_state_quit_early, {});
    }

    LOCK(m_pool.cs);
    // Stores results from which we will create the returned PackageMempoolAcceptResult.
    // A result may be changed if a mempool transaction is evicted later due to LimitMempoolSize().
    std::map<Wtxid, MempoolAcceptResult> results_final;
    // Results from individual validation which will be returned if no other result is available for
    // this transaction. "Nonfinal" because if a transaction fails by itself but succeeds later
    // (i.e. when evaluated with a fee-bumping child), the result in this map may be discarded.
    std::map<Wtxid, MempoolAcceptResult> individual_results_nonfinal;
    // Tracks whether we think package submission could result in successful entry to the mempool
    bool quit_early{false};
    std::vector<CTransactionRef> txns_package_eval;
    for (const auto& tx : package) {
        const auto& wtxid = tx->GetWitnessHash();
        const auto& txid = tx->GetHash();
        // There are 3 possibilities: already in mempool, same-txid-diff-wtxid already in mempool,
        // or not in mempool. An already confirmed tx is treated as one not in mempool, because all
        // we know is that the inputs aren't available.
        if (m_pool.exists(wtxid)) {
            // Exact transaction already exists in the mempool.
            // Node operators are free to set their mempool policies however they please, nodes may receive
            // transactions in different orders, and malicious counterparties may try to take advantage of
            // policy differences to pin or delay propagation of transactions. As such, it's possible for
            // some package transaction(s) to already be in the mempool, and we don't want to reject the
            // entire package in that case (as that could be a censorship vector). De-duplicate the
            // transactions that are already in the mempool, and only call AcceptMultipleTransactions() with
            // the new transactions. This ensures we don't double-count transaction counts and sizes when
            // checking ancestor/descendant limits, or double-count transaction fees for fee-related policy.
            const auto& entry{*Assert(m_pool.GetEntry(txid))};
            results_final.emplace(wtxid, MempoolAcceptResult::MempoolTx(entry.GetTxSize(), entry.GetFee()));
        } else if (m_pool.exists(txid)) {
            // Transaction with the same non-witness data but different witness (same txid,
            // different wtxid) already exists in the mempool.
            //