InvariantCheck.cpp

#include <xrpl/tx/invariants/InvariantCheck.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/beast/utility/Zero.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/ledger/helpers/AccountRootHelpers.h>
#include <xrpl/ledger/helpers/TokenHelpers.h>
#include <xrpl/protocol/AccountID.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/Issue.h>
#include <xrpl/protocol/Keylet.h>
#include <xrpl/protocol/LedgerFormats.h>
#include <xrpl/protocol/MPTIssue.h>
#include <xrpl/protocol/Protocol.h>
#include <xrpl/protocol/Rules.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STNumber.h>  // IWYU pragma: keep
#include <xrpl/protocol/STTx.h>
#include <xrpl/protocol/SystemParameters.h>
#include <xrpl/protocol/TER.h>
#include <xrpl/protocol/TxFormats.h>
#include <xrpl/protocol/UintTypes.h>
#include <xrpl/protocol/XRPAmount.h>
#include <xrpl/tx/invariants/InvariantCheckPrivilege.h>
 
#include <algorithm>
#include <cstdint>
#include <functional>
#include <memory>
#include <optional>
#include <sstream>
#include <string>
#include <vector>
 
namespace xrpl {
 
#pragma push_macro("TRANSACTION")
#undef TRANSACTION
 
#define TRANSACTION(tag, value, name, delegable, amendment, privileges, ...) \
    case tag: {                                                              \
        return (privileges) & priv;                                          \
    }
 
bool
hasPrivilege(STTx const& tx, Privilege priv)
{
    switch (tx.getTxnType())
    {
#include <xrpl/protocol/detail/transactions.macro>
 
        // Deprecated types
        default:
            return false;
    }
};
 
#undef TRANSACTION
#pragma pop_macro("TRANSACTION")
 
// Returns the human-readable name of a ledger entry's type, falling back to
// the numeric type if the format is somehow unknown.
static std::string
ledgerEntryTypeName(SLE const& sle)
{
    auto const item = LedgerFormats::getInstance().findByType(sle.getType());
 
    if (item == nullptr)
    {
        // LCOV_EXCL_START
        UNREACHABLE("xrpl::ledgerEntryTypeName : ledger entry has no known ledger format");
        return std::to_string(sle.getType());
        // LCOV_EXCL_STOP
    }
    return item->getName();
}
 
void
TransactionFeeCheck::visitEntry(bool, SLE::const_ref, SLE::const_ref)
{
    // nothing to do
}
 
bool
TransactionFeeCheck::finalize(
    STTx const& tx,
    TER const,
    XRPAmount const fee,
    ReadView const&,
    beast::Journal const& j)
{
    // We should never charge a negative fee
    if (fee.drops() < 0)
    {
        JLOG(j.fatal()) << "Invariant failed: fee paid was negative: " << fee.drops();
        return false;
    }
 
    // We should never charge a fee that's greater than or equal to the
    // entire XRP supply.
    if (fee >= kInitialXrp)
    {
        JLOG(j.fatal()) << "Invariant failed: fee paid exceeds system limit: " << fee.drops();
        return false;
    }
 
    // We should never charge more for a transaction than the transaction
    // authorizes. It's possible to charge less in some circumstances.
    if (fee > tx.getFieldAmount(sfFee).xrp())
    {
        JLOG(j.fatal()) << "Invariant failed: fee paid is " << fee.drops()
                        << " exceeds fee specified in transaction.";
        return false;
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
XRPNotCreated::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    /* We go through all modified ledger entries, looking only at account roots,
     * escrow payments, and payment channels. We remove from the total any
     * previous XRP values and add to the total any new XRP values. The net
     * balance of a payment channel is computed from two fields (amount and
     * balance) and deletions are ignored for paychan and escrow because the
     * amount fields have not been adjusted for those in the case of deletion.
     */
    if (before)
    {
        switch (before->getType())
        {
            case ltACCOUNT_ROOT:
                drops_ -= (*before)[sfBalance].xrp().drops();
                break;
            case ltPAYCHAN:
                drops_ -= ((*before)[sfAmount] - (*before)[sfBalance]).xrp().drops();
                break;
            case ltESCROW:
                if (isXRP((*before)[sfAmount]))
                    drops_ -= (*before)[sfAmount].xrp().drops();
                break;
            case ltSPONSORSHIP:
                if (before->isFieldPresent(sfFeeAmount))
                {
                    XRPL_ASSERT(
                        isXRP((*before)[sfFeeAmount]),
                        "XRPNotCreated::visitEntry : Sponsorship.FeeAmount is XRP");
                    drops_ -= (*before)[sfFeeAmount].xrp().drops();
                }
                break;
            default:
                break;
        }
    }
 
    if (!after)
    {
        // LCOV_EXCL_START
        UNREACHABLE("xrpl::XRPNotCreated::visitEntry : after can't be null");
        return;
        // LCOV_EXCL_STOP
    }
    switch (after->getType())
    {
        case ltACCOUNT_ROOT:
            drops_ += (*after)[sfBalance].xrp().drops();
            break;
        case ltPAYCHAN:
            if (!isDelete)
                drops_ += ((*after)[sfAmount] - (*after)[sfBalance]).xrp().drops();
            break;
        case ltESCROW:
            if (!isDelete && isXRP((*after)[sfAmount]))
                drops_ += (*after)[sfAmount].xrp().drops();
            break;
        case ltSPONSORSHIP:
            if (!isDelete && after->isFieldPresent(sfFeeAmount))
            {
                XRPL_ASSERT(
                    isXRP((*after)[sfFeeAmount]),
                    "XRPNotCreated::visitEntry : Sponsorship.FeeAmount is XRP");
                drops_ += (*after)[sfFeeAmount].xrp().drops();
            }
            break;
        default:
            break;
    }
}
 
bool
XRPNotCreated::finalize(
    STTx const& tx,
    TER const,
    XRPAmount const fee,
    ReadView const&,
    beast::Journal const& j) const
{
    // The net change should never be positive, as this would mean that the
    // transaction created XRP out of thin air. That's not possible.
    if (drops_ > 0)
    {
        JLOG(j.fatal()) << "Invariant failed: XRP net change was positive: " << drops_;
        return false;
    }
 
    // The negative of the net change should be equal to actual fee charged.
    if (-drops_ != fee.drops())
    {
        JLOG(j.fatal()) << "Invariant failed: XRP net change of " << drops_ << " doesn't match fee "
                        << fee.drops();
        return false;
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
XRPBalanceChecks::visitEntry(bool, SLE::const_ref before, SLE::const_ref after)
{
    auto isBad = [](STAmount const& balance) {
        if (!balance.native())
            return true;
 
        auto const drops = balance.xrp();
 
        // Can't have more than the number of drops instantiated
        // in the genesis ledger.
        if (drops > kInitialXrp)
            return true;
 
        // Can't have a negative balance (0 is OK)
        if (drops < XRPAmount{0})
            return true;
 
        return false;
    };
 
    if (before && before->getType() == ltACCOUNT_ROOT)
        bad_ |= isBad((*before)[sfBalance]);
 
    if (after && after->getType() == ltACCOUNT_ROOT)
        bad_ |= isBad((*after)[sfBalance]);
}
 
bool
XRPBalanceChecks::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if (bad_)
    {
        JLOG(j.fatal()) << "Invariant failed: incorrect account XRP balance";
        return false;
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
NoBadOffers::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    auto isBad = [](STAmount const& pays, STAmount const& gets) {
        // An offer should never be negative
        if (pays < beast::kZero)
            return true;
 
        if (gets < beast::kZero)
            return true;
 
        // Can't have an XRP to XRP offer:
        return pays.native() && gets.native();
    };
 
    if (before && before->getType() == ltOFFER)
        bad_ |= isBad((*before)[sfTakerPays], (*before)[sfTakerGets]);
 
    if (after && after->getType() == ltOFFER)
        bad_ |= isBad((*after)[sfTakerPays], (*after)[sfTakerGets]);
}
 
bool
NoBadOffers::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if (bad_)
    {
        JLOG(j.fatal()) << "Invariant failed: offer with a bad amount";
        return false;
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
NoZeroEscrow::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    auto isBad = [](STAmount const& amount) {
        // XRP case
        if (amount.native())
        {
            if (amount.xrp() <= XRPAmount{0})
                return true;
 
            if (amount.xrp() >= kInitialXrp)
                return true;
        }
        else
        {
            return amount.asset().visit(
                [&](Issue const& issue) {
                    // IOU case
                    if (amount <= beast::kZero)
                        return true;
 
                    if (badCurrency() == issue.currency)
                        return true;
 
                    return false;
                }
 
                // MPT case
                ,
                [&](MPTIssue const&) {
                    if (amount <= beast::kZero)
                        return true;
 
                    if (amount.mpt() > MPTAmount{kMaxMpTokenAmount})
                        return true;  // LCOV_EXCL_LINE
 
                    return false;
                });
        }
        return false;
    };
 
    if (before && before->getType() == ltESCROW)
        bad_ |= isBad((*before)[sfAmount]);
 
    if (after && after->getType() == ltESCROW)
        bad_ |= isBad((*after)[sfAmount]);
 
    auto checkAmount = [this](std::int64_t amount) {
        if (amount > kMaxMpTokenAmount || amount < 0)
            bad_ |= true;
    };
 
    bool const overwriteFixEnabled = isFeatureEnabled(fixCleanup3_1_3, true);
 
    if (after && after->getType() == ltMPTOKEN_ISSUANCE)
    {
        auto const outstanding = (*after)[sfOutstandingAmount];
        checkAmount(outstanding);
        if (auto const locked = (*after)[~sfLockedAmount])
        {
            checkAmount(*locked);
            bool const isBad = outstanding < *locked;
            if (overwriteFixEnabled)
            {
                bad_ |= isBad;
            }
            else
            {
                bad_ = isBad;
            }
        }
    }
 
    if (after && after->getType() == ltMPTOKEN)
    {
        auto const mptAmount = (*after)[sfMPTAmount];
        checkAmount(mptAmount);
        if (auto const locked = (*after)[~sfLockedAmount])
        {
            checkAmount(*locked);
        }
    }
}
 
bool
NoZeroEscrow::finalize(
    STTx const& txn,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if (bad_)
    {
        JLOG(j.fatal()) << "Invariant failed: escrow specifies invalid amount";
        return false;
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
AccountRootsNotDeleted::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref)
{
    if (isDelete && before && before->getType() == ltACCOUNT_ROOT)
        accountsDeleted_++;
}
 
bool
AccountRootsNotDeleted::finalize(
    STTx const& tx,
    TER const result,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    // AMM account root can be deleted as the result of AMM withdraw/delete
    // transaction when the total AMM LP Tokens balance goes to 0.
    // A successful AccountDelete or AMMDelete MUST delete exactly
    // one account root.
    if (hasPrivilege(tx, MustDeleteAcct) && isTesSuccess(result))
    {
        if (accountsDeleted_ == 1)
            return true;
 
        if (accountsDeleted_ == 0)
        {
            JLOG(j.fatal()) << "Invariant failed: account deletion "
                               "succeeded without deleting an account";
        }
        else
        {
            JLOG(j.fatal()) << "Invariant failed: account deletion "
                               "succeeded but deleted multiple accounts!";
        }
        return false;
    }
 
    // A successful AMMWithdraw/AMMClawback MAY delete one account root
    // when the total AMM LP Tokens balance goes to 0. Not every AMM withdraw
    // deletes the AMM account, accountsDeleted_ is set if it is deleted.
    if (hasPrivilege(tx, MayDeleteAcct) && isTesSuccess(result) && accountsDeleted_ == 1)
        return true;
 
    if (accountsDeleted_ == 0)
        return true;
 
    JLOG(j.fatal()) << "Invariant failed: an account root was deleted";
    return false;
}
 
//------------------------------------------------------------------------------
 
void
AccountRootsDeletedClean::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    if (isDelete && before && before->getType() == ltACCOUNT_ROOT)
        accountsDeleted_.emplace_back(before, after);
}
 
bool
AccountRootsDeletedClean::finalize(
    STTx const& tx,
    TER const result,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j)
{
    // Always check for objects in the ledger, but to prevent differing
    // transaction processing results, however unlikely, only fail if the
    // feature is enabled. Enabled, or not, though, a fatal-level message will
    // be logged
    [[maybe_unused]] bool const enforce = view.rules().enabled(fixCleanup3_2_0) ||
        view.rules().enabled(featureSponsor) || view.rules().enabled(featureSingleAssetVault) ||
        view.rules().enabled(featureLendingProtocol);
 
    auto const objectExists = [&view, enforce, &j](auto const& keylet) {
        (void)enforce;
        if (auto const sle = view.read(keylet))
        {
            // Finding the object is bad
            JLOG(j.fatal()) << "Invariant failed: account deletion left behind a "
                            << ledgerEntryTypeName(*sle) << " object";
            // The comment above starting with "assert(enforce)" explains this
            // assert.
            XRPL_ASSERT(
                enforce,
                "xrpl::AccountRootsDeletedClean::finalize::objectExists : "
                "account deletion left no objects behind");
            return true;
        }
        return false;
    };
 
    for (auto const& [before, after] : accountsDeleted_)
    {
        auto const accountID = before->getAccountID(sfAccount);
        // An account should not be deleted with a balance
        if (after->at(sfBalance) != beast::kZero)
        {
            JLOG(j.fatal()) << "Invariant failed: account deletion left "
                               "behind a non-zero balance";
            XRPL_ASSERT(
                enforce,
                "xrpl::AccountRootsDeletedClean::finalize : "
                "deleted account has zero balance");
            if (enforce)
                return false;
        }
        // An account should not be deleted with a non-zero owner count
        if (after->at(sfOwnerCount) != 0)
        {
            JLOG(j.fatal()) << "Invariant failed: account deletion left "
                               "behind a non-zero owner count";
            XRPL_ASSERT(
                enforce,
                "xrpl::AccountRootsDeletedClean::finalize : "
                "deleted account has zero owner count");
            if (enforce)
                return false;
        }
        // An account should not be deleted with sponsorship fields
        if (after->isFieldPresent(sfSponsoredOwnerCount) ||
            after->isFieldPresent(sfSponsoringOwnerCount) ||
            after->isFieldPresent(sfSponsoringAccountCount) || after->isFieldPresent(sfSponsor))
        {
            JLOG(j.fatal()) << "Invariant failed: account deletion left "
                               "behind a sponsorship field";
            XRPL_ASSERT(
                enforce,
                "xrpl::AccountRootsDeletedClean::finalize : "
                "deleted account has no sponsorship fields");
            if (enforce)
                return false;
        }
        // Simple types
        for (auto const& [keyletfunc, _1, _2] : kDirectAccountKeylets)
        {
            // TODO: use '_' for both unused variables above once we are in C++26
            if (objectExists(std::invoke(keyletfunc, accountID)) && enforce)
                return false;
        }
 
        {
            // NFT pages. nftpage_min and nftpage_max were already explicitly
            // checked above as entries in directAccountKeylets. This uses
            // view.succ() to check for any NFT pages in between the two
            // endpoints.
            Keylet const first = keylet::nftokenPageMin(accountID);
            Keylet const last = keylet::nftokenPageMax(accountID);
 
            std::optional<uint256> key = view.succ(first.key, last.key.next());
 
            // current page
            if (key && objectExists(Keylet{ltNFTOKEN_PAGE, *key}) && enforce)
                return false;
        }
 
        // If the account is a pseudo account, then the linked object must
        // also be deleted. e.g. AMM, Vault, etc.
        for (auto const& field : getPseudoAccountFields())
        {
            if (before->isFieldPresent(*field))
            {
                auto const key = before->getFieldH256(*field);
                if (objectExists(keylet::unchecked(key)) && enforce)
                    return false;
            }
        }
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
LedgerEntryTypesMatch::visitEntry(bool, SLE::const_ref before, SLE::const_ref after)
{
    if (before && after && before->getType() != after->getType())
        typeMismatch_ = true;
 
    if (after)
    {
#pragma push_macro("LEDGER_ENTRY")
#undef LEDGER_ENTRY
 
#define LEDGER_ENTRY(tag, ...) case tag:
 
        switch (after->getType())
        {
#include <xrpl/protocol/detail/ledger_entries.macro>
 
            break;
            default:
                invalidTypeAdded_ = true;
                break;
        }
 
#undef LEDGER_ENTRY
#pragma pop_macro("LEDGER_ENTRY")
    }
}
 
bool
LedgerEntryTypesMatch::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if ((!typeMismatch_) && (!invalidTypeAdded_))
        return true;
 
    if (typeMismatch_)
    {
        JLOG(j.fatal()) << "Invariant failed: ledger entry type mismatch";
    }
 
    if (invalidTypeAdded_)
    {
        JLOG(j.fatal()) << "Invariant failed: invalid ledger entry type added";
    }
 
    return false;
}
 
//------------------------------------------------------------------------------
 
void
NoXRPTrustLines::visitEntry(bool, SLE::const_ref, SLE::const_ref after)
{
    bool const overwriteFixEnabled = isFeatureEnabled(fixCleanup3_1_3, true);
 
    if (after && after->getType() == ltRIPPLE_STATE)
    {
        // checking the issue directly here instead of
        // relying on .native() just in case native somehow
        // were systematically incorrect
        bool const isXrp = after->getFieldAmount(sfLowLimit).asset() == xrpIssue() ||
            after->getFieldAmount(sfHighLimit).asset() == xrpIssue();
        if (overwriteFixEnabled)
        {
            xrpTrustLine_ |= isXrp;
        }
        else
        {
            xrpTrustLine_ = isXrp;
        }
    }
}
 
bool
NoXRPTrustLines::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if (!xrpTrustLine_)
        return true;
 
    JLOG(j.fatal()) << "Invariant failed: an XRP trust line was created";
    return false;
}
 
//------------------------------------------------------------------------------
 
void
NoDeepFreezeTrustLinesWithoutFreeze::visitEntry(bool, SLE::const_ref, SLE::const_ref after)
{
    if (after && after->getType() == ltRIPPLE_STATE)
    {
        bool const overwriteFixEnabled = isFeatureEnabled(fixCleanup3_1_3, true);
 
        bool const lowFreeze = after->isFlag(lsfLowFreeze);
        bool const lowDeepFreeze = after->isFlag(lsfLowDeepFreeze);
 
        bool const highFreeze = after->isFlag(lsfHighFreeze);
        bool const highDeepFreeze = after->isFlag(lsfHighDeepFreeze);
 
        bool const bad = (lowDeepFreeze && !lowFreeze) || (highDeepFreeze && !highFreeze);
        if (overwriteFixEnabled)
        {
            deepFreezeWithoutFreeze_ |= bad;
        }
        else
        {
            deepFreezeWithoutFreeze_ = bad;
        }
    }
}
 
bool
NoDeepFreezeTrustLinesWithoutFreeze::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const&,
    beast::Journal const& j) const
{
    if (!deepFreezeWithoutFreeze_)
        return true;
 
    JLOG(j.fatal()) << "Invariant failed: a trust line with deep freeze flag "
                       "without normal freeze was created";
    return false;
}
 
//------------------------------------------------------------------------------
 
void
ValidNewAccountRoot::visitEntry(bool, SLE::const_ref before, SLE::const_ref after)
{
    if (!before && after->getType() == ltACCOUNT_ROOT)
    {
        accountsCreated_++;
        accountSeq_ = (*after)[sfSequence];
        pseudoAccount_ = isPseudoAccount(after);
        flags_ = after->getFlags();
    }
}
 
bool
ValidNewAccountRoot::finalize(
    STTx const& tx,
    TER const result,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j) const
{
    if (accountsCreated_ == 0)
        return true;
 
    if (accountsCreated_ > 1)
    {
        JLOG(j.fatal()) << "Invariant failed: multiple accounts "
                           "created in a single transaction";
        return false;
    }
 
    // From this point on we know exactly one account was created.
    if (hasPrivilege(tx, CreateAcct | CreatePseudoAcct) && isTesSuccess(result))
    {
        bool const pseudoAccount =
            (pseudoAccount_ &&
             (view.rules().enabled(featureSingleAssetVault) ||
              view.rules().enabled(featureLendingProtocol)));
 
        if (pseudoAccount && !hasPrivilege(tx, CreatePseudoAcct))
        {
            JLOG(j.fatal()) << "Invariant failed: pseudo-account created by a "
                               "wrong transaction type";
            return false;
        }
 
        std::uint32_t const startingSeq = pseudoAccount ? 0 : view.seq();
 
        if (accountSeq_ != startingSeq)
        {
            JLOG(j.fatal()) << "Invariant failed: account created with "
                               "wrong starting sequence number";
            return false;
        }
 
        if (pseudoAccount)
        {
            std::uint32_t const expected = (lsfDisableMaster | lsfDefaultRipple | lsfDepositAuth);
            if (flags_ != expected)
            {
                JLOG(j.fatal()) << "Invariant failed: pseudo-account created with "
                                   "wrong flags";
                return false;
            }
        }
 
        return true;
    }
 
    JLOG(j.fatal()) << "Invariant failed: account root created illegally";
    return false;
}  // namespace xrpl
 
//------------------------------------------------------------------------------
 
static std::optional<STAmount>
clawbackTrustLineBalanceInHolderTerms(
    SLE::const_pointer const& sle,
    AccountID const& holder,
    AccountID const& issuer,
    Currency const& currency)
{
    if (!sle)
        return STAmount{Issue{currency, issuer}};
 
    if (sle->getType() != ltRIPPLE_STATE ||
        sle->key() != keylet::trustLine(holder, issuer, currency).key)
    {
        return std::nullopt;
    }
 
    STAmount balance = sle->getFieldAmount(sfBalance);
    if (holder > issuer)
        balance.negate();
    balance.get<Issue>().account = issuer;
    return balance;
}
 
void
ValidClawback::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    if (before && before->getType() == ltRIPPLE_STATE)
    {
        trustlinesChanged_++;
        iou_.before = before;
    }
 
    if (!isDelete && after && after->getType() == ltRIPPLE_STATE)
        iou_.after = after;
 
    if (before && before->getType() == ltMPTOKEN)
    {
        mptokensChanged_++;
        mpt_.before = before;
    }
 
    if (!isDelete && after && after->getType() == ltMPTOKEN)
        mpt_.after = after;
}
 
bool
ValidClawback::finalize(
    STTx const& tx,
    TER const result,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j) const
{
    if (tx.getTxnType() != ttCLAWBACK)
        return true;
 
    if (isTesSuccess(result))
    {
        if (trustlinesChanged_ > 1)
        {
            JLOG(j.fatal()) << "Invariant failed: more than one trustline changed.";
            return false;
        }
 
        if (mptokensChanged_ > 1)
        {
            JLOG(j.fatal()) << "Invariant failed: more than one mptokens changed.";
            return false;
        }
 
        bool const mptV2Enabled = view.rules().enabled(featureMPTokensV2);
        if (trustlinesChanged_ != 0 && mptokensChanged_ != 0)
        {
            JLOG(j.fatal()) << "Invariant failed: trustline and MPToken both changed.";
            if (mptV2Enabled)
                return false;
        }
 
        if (trustlinesChanged_ == 1 || (mptV2Enabled && mptokensChanged_ == 1))
        {
            STAmount const& amount = tx.getFieldAmount(sfAmount);
 
            return amount.asset().visit(
                [&](Issue const& issue) {
                    AccountID const issuer = tx.getAccountID(sfAccount);
                    AccountID const& holder = amount.getIssuer();
                    STAmount const holderBalance = accountHolds(
                        view, holder, issue.currency, issuer, FreezeHandling::IgnoreFreeze, j);
 
                    if (holderBalance.signum() < 0)
                    {
                        JLOG(j.fatal()) << "Invariant failed: trustline or MPT balance is negative";
                        return false;
                    }
 
                    if (!iou_.before)
                    {
                        JLOG(j.fatal())
                            << "Invariant failed: trustline clawback changed the wrong line";
                        return !mptV2Enabled;
                    }
 
                    auto const beforeBalance = clawbackTrustLineBalanceInHolderTerms(
                        iou_.before, holder, issuer, issue.currency);
                    auto const afterBalance = clawbackTrustLineBalanceInHolderTerms(
                        iou_.after, holder, issuer, issue.currency);
                    if (!beforeBalance || !afterBalance)
                    {
                        JLOG(j.fatal())
                            << "Invariant failed: trustline clawback changed the wrong line";
                        return !mptV2Enabled;
                    }
 
                    STAmount clawAmount = amount;
                    clawAmount.get<Issue>().account = issuer;
                    if (clawAmount <= beast::kZero)
                    {
                        JLOG(j.fatal()) << "Invariant failed: trustline clawback amount is invalid";
                        return !mptV2Enabled;
                    }
 
                    if (*afterBalance > *beforeBalance ||
                        (*beforeBalance - *afterBalance) != std::min(*beforeBalance, clawAmount))
                    {
                        JLOG(j.fatal())
                            << "Invariant failed: trustline clawback balance change is invalid";
                        return !mptV2Enabled;
                    }
 
                    return true;
                },
                [&](MPTIssue const& issue) {
                    auto const holder = tx[~sfHolder];
                    if (!holder)
                    {
                        JLOG(j.fatal()) << "Invariant failed: MPT clawback missing holder";
                        return !mptV2Enabled;
                    }
 
                    if (!mpt_.before || !mpt_.after)
                    {
                        JLOG(j.fatal()) << "Invariant failed: MPT clawback token is missing";
                        return !mptV2Enabled;
                    }
 
                    if (mpt_.before->getAccountID(sfAccount) != *holder ||
                        mpt_.after->getAccountID(sfAccount) != *holder ||
                        (*mpt_.before)[sfMPTokenIssuanceID] != issue.getMptID() ||
                        (*mpt_.after)[sfMPTokenIssuanceID] != issue.getMptID())
                    {
                        JLOG(j.fatal()) << "Invariant failed: MPT clawback changed the wrong token";
                        return !mptV2Enabled;
                    }
 
                    auto const before = mpt_.before->getFieldU64(sfMPTAmount);
                    auto const after = mpt_.after->getFieldU64(sfMPTAmount);
                    if (amount.negative() || amount.mantissa() == 0)
                    {
                        JLOG(j.fatal()) << "Invariant failed: MPT clawback amount is invalid";
                        return !mptV2Enabled;
                    }
                    auto const clawAmount = amount.mantissa();
 
                    // MPT balances are unsigned, so validate the raw holder
                    // debit instead of routing through accountHolds().
                    if (after > before || (before - after) != std::min(before, clawAmount))
                    {
                        JLOG(j.fatal())
                            << "Invariant failed: MPT clawback balance change is invalid";
                        return !mptV2Enabled;
                    }
 
                    return true;
                });
        }
    }
    else
    {
        if (trustlinesChanged_ != 0)
        {
            JLOG(j.fatal()) << "Invariant failed: some trustlines were changed "
                               "despite failure of the transaction.";
            return false;
        }
 
        if (mptokensChanged_ != 0)
        {
            JLOG(j.fatal()) << "Invariant failed: some mptokens were changed "
                               "despite failure of the transaction.";
            return false;
        }
    }
 
    return true;
}
 
//------------------------------------------------------------------------------
 
void
ValidPseudoAccounts::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    if (isDelete)
    {
        // Deletion is ignored
        return;
    }
 
    if (after && after->getType() == ltACCOUNT_ROOT)
    {
        bool const isPseudo = [&]() {
            // isPseudoAccount checks that any of the pseudo-account fields are
            // set.
            if (isPseudoAccount(after))
                return true;
            // Not all pseudo-accounts have a zero sequence, but all accounts
            // with a zero sequence had better be pseudo-accounts.
            if (after->at(sfSequence) == 0)
                return true;
 
            return false;
        }();
        if (isPseudo)
        {
            // Pseudo accounts must have the following properties:
            // 1. Exactly one of the pseudo-account fields is set.
            // 2. The sequence number is not changed.
            // 3. The lsfDisableMaster, lsfDefaultRipple, and lsfDepositAuth
            //    flags are set.
            // 4. The RegularKey is not set.
            // 5. The SponsoredOwnerCount, SponsoringOwnerCount, SponsoringAccountCount, Sponsor
            //    fields are not set.
            {
                std::vector<SField const*> const& fields = getPseudoAccountFields();
 
                auto const numFields = std::ranges::count_if(
                    fields,
                    [&after](SField const* sf) -> bool { return after->isFieldPresent(*sf); });
                if (numFields != 1)
                {
                    std::stringstream error;
                    error << "pseudo-account has " << numFields << " pseudo-account fields set";
                    errors_.emplace_back(error.str());
                }
            }
            if (before && before->at(sfSequence) != after->at(sfSequence))
            {
                errors_.emplace_back("pseudo-account sequence changed");
            }
            if (!after->isFlag(lsfDisableMaster | lsfDefaultRipple | lsfDepositAuth))
            {
                errors_.emplace_back("pseudo-account flags are not set");
            }
            if (after->isFieldPresent(sfRegularKey))
            {
                errors_.emplace_back("pseudo-account has a regular key");
            }
            if (after->isFieldPresent(sfSponsoredOwnerCount) ||
                after->isFieldPresent(sfSponsoringOwnerCount) || after->isFieldPresent(sfSponsor) ||
                after->isFieldPresent(sfSponsoringAccountCount))
            {
                errors_.emplace_back("pseudo-account has a sponsorship field");
            }
        }
    }
}
 
bool
ValidPseudoAccounts::finalize(
    STTx const& tx,
    TER const,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j)
{
    bool const enforce = view.rules().enabled(featureSingleAssetVault);
    XRPL_ASSERT(
        errors_.empty() || enforce,
        "xrpl::ValidPseudoAccounts::finalize : no bad "
        "changes or enforce invariant");
    if (!errors_.empty())
    {
        for (auto const& error : errors_)
        {
            JLOG(j.fatal()) << "Invariant failed: " << error;
        }
        if (enforce)
            return false;
    }
    return true;
}
 
//------------------------------------------------------------------------------
 
void
NoModifiedUnmodifiableFields::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    if (isDelete || !before)
    {
        // Creation and deletion are ignored
        return;
    }
 
    changedEntries_.emplace(before, after);
}
 
bool
NoModifiedUnmodifiableFields::finalize(
    STTx const& tx,
    TER const,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j)
{
    static auto const kFieldChanged = [](auto const& before, auto const& after, auto const& field) {
        bool const beforeField = before->isFieldPresent(field);
        bool const afterField = after->isFieldPresent(field);
        return beforeField != afterField || (afterField && before->at(field) != after->at(field));
    };
    for (auto const& slePair : changedEntries_)
    {
        auto const& before = slePair.first;
        auto const& after = slePair.second;
        auto const type = after->getType();
        // featureLendingProtocol gates enforcement, not detection: changes are
        // always logged, but the transaction is only failed once the amendment
        // is enabled. Type-specific field lists may add their own gates (see
        // ltVAULT).
        bool const enforce = view.rules().enabled(featureLendingProtocol);
        bool bad = kFieldChanged(before, after, sfLedgerEntryType) ||
            kFieldChanged(before, after, sfLedgerIndex);
        switch (type)
        {
            case ltLOAN_BROKER:
                bad = bad || kFieldChanged(before, after, sfSequence) ||
                    kFieldChanged(before, after, sfOwnerNode) ||
                    kFieldChanged(before, after, sfVaultNode) ||
                    kFieldChanged(before, after, sfVaultID) ||
                    kFieldChanged(before, after, sfAccount) ||
                    kFieldChanged(before, after, sfOwner) ||
                    kFieldChanged(before, after, sfManagementFeeRate) ||
                    kFieldChanged(before, after, sfCoverRateMinimum) ||
                    kFieldChanged(before, after, sfCoverRateLiquidation);
                break;
            case ltLOAN:
                bad = bad || kFieldChanged(before, after, sfSequence) ||
                    kFieldChanged(before, after, sfOwnerNode) ||
                    kFieldChanged(before, after, sfLoanBrokerNode) ||
                    kFieldChanged(before, after, sfLoanBrokerID) ||
                    kFieldChanged(before, after, sfBorrower) ||
                    kFieldChanged(before, after, sfLoanOriginationFee) ||
                    kFieldChanged(before, after, sfLoanServiceFee) ||
                    kFieldChanged(before, after, sfLatePaymentFee) ||
                    kFieldChanged(before, after, sfClosePaymentFee) ||
                    kFieldChanged(before, after, sfOverpaymentFee) ||
                    kFieldChanged(before, after, sfInterestRate) ||
                    kFieldChanged(before, after, sfLateInterestRate) ||
                    kFieldChanged(before, after, sfCloseInterestRate) ||
                    kFieldChanged(before, after, sfOverpaymentInterestRate) ||
                    kFieldChanged(before, after, sfStartDate) ||
                    kFieldChanged(before, after, sfPaymentInterval) ||
                    kFieldChanged(before, after, sfGracePeriod) ||
                    kFieldChanged(before, after, sfLoanScale);
                break;
            case ltVAULT:
                /*
                 * sfAccount, sfAsset and sfShareMPTID are already
                 * captured by VaultInvariant. The additional fields
                 * below are introduced by featureLendingProtocolV1_1
                 * and only exist on V1_1 vaults.
                 */
                if (view.rules().enabled(featureLendingProtocolV1_1))
                {
                    bad = bad || kFieldChanged(before, after, sfVaultKind) ||
                        kFieldChanged(before, after, sfSubscriptionDate) ||
                        kFieldChanged(before, after, sfRedemptionDate) ||
                        kFieldChanged(before, after, sfSequence) ||
                        kFieldChanged(before, after, sfOwnerNode) ||
                        kFieldChanged(before, after, sfOwner) ||
                        kFieldChanged(before, after, sfWithdrawalPolicy) ||
                        kFieldChanged(before, after, sfScale) ||
                        kFieldChanged(before, after, sfLEVersion);
                }
                break;
            default:
                break;
        }
        XRPL_ASSERT(
            !bad || enforce,
            "xrpl::NoModifiedUnmodifiableFields::finalize : no bad "
            "changes or enforce invariant");
        if (bad)
        {
            JLOG(j.fatal()) << "Invariant failed: changed an unchangeable field for "
                            << tx.getTransactionID();
            if (enforce)
                return false;
        }
    }
    return true;
}
 
void
ValidAmounts::visitEntry(
    bool isDelete,
    std::shared_ptr<SLE const> const&,
    std::shared_ptr<SLE const> const& after)
{
    if (!isDelete && after)
        afterEntries_.push_back(after);
}
 
bool
ValidAmounts::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j) const
{
    bool const badLedgerEntry = std::ranges::any_of(
        afterEntries_, [&](auto const& sle) { return hasInvalidAmount(*sle, j); });
 
    if (badLedgerEntry)
    {
        JLOG(j.fatal())
            << "Invariant failed: ledger entry contains non-canonical MPT or XRP amount";
        return !view.rules().enabled(fixCleanup3_2_0);
    }
 
    return true;
}
 
void
ObjectHasPseudoAccount::visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after)
{
    if (!isDelete)
        return;
 
    // Before should never be null when isDelete = true
    if (!before)
    {
        // LCOV_EXCL_START
        UNREACHABLE(
            "xrpl::ObjectHasPseudoAccount::visitEntry : deleted ledger entry missing before state");
        return;
        // LCOV_EXCL_STOP
    }
 
    switch (before->getType())
    {
        case ltAMM:
        case ltVAULT:
        case ltLOAN_BROKER:
            deletedObjSles_.push_back(before);
            break;
        default:
            return;
    }
}
 
[[nodiscard]] bool
ObjectHasPseudoAccount::finalize(
    STTx const&,
    TER const,
    XRPAmount const,
    ReadView const& view,
    beast::Journal const& j) const
{
    if (!view.rules().enabled(fixCleanup3_3_0))
        return true;
 
    if (deletedObjSles_.empty())
        return true;
 
    bool failed = false;
    for (auto const& sle : deletedObjSles_)
    {
        if (!sle->isFieldPresent(sfAccount))
        {
            JLOG(j.fatal()) << "Invariant failed: deleted " << ledgerEntryTypeName(*sle)
                            << " is missing pseudo-account field";
            failed = true;
            continue;
        }
 
        // The pseudo-account must NOT exist on the ledger after the object is deleted.
        if (view.exists(keylet::account(sle->getAccountID(sfAccount))))
        {
            JLOG(j.fatal()) << "Invariant failed: deleted " << ledgerEntryTypeName(*sle)
                            << " without deleting its pseudo-account";
            failed = true;
        }
    }
 
    return !failed;
}
 
}  // namespace xrpl