adds LEVersion field to Vault

include/xrpl/ledger/helpers/LendingHelpers.h

@@ -304,7 +304,7 @@ loanOriginationDeltas(Number const& principalRequested, Number const& interestDu
 
 // LoanManage impair/unimpair/default: the vault's exposure to this loan
 Number
-loanVaultExposure(SLE::ref loanSle);
+loanVaultExposure(SLE::const_ref loanSle);
 
 // LoanPay: what's added to Vault.AssetsTotal and subtracted from LoanBroker.DebtTotal for a payment
 AccountingDeltas
@@ -317,10 +317,10 @@ loanPaymentDeltas(LoanPaymentParts const& parts);
 namespace CashBasis {
 
 AccountingDeltas
-loanOriginationDeltas(Number const& principalRequested, Number const& interestDue);
+loanOriginationDeltas(Number const& principalRequested);
 
 Number
-loanVaultExposure(SLE::ref loanSle);
+loanVaultExposure(SLE::const_ref loanSle);
 
 AccountingDeltas
 loanPaymentDeltas(LoanPaymentParts const& parts);
@@ -328,18 +328,21 @@ loanPaymentDeltas(LoanPaymentParts const& parts);
 }  // namespace CashBasis
 
 // Public dispatchers: pick CashBasis:: if featureLendingProtocolV1_1 is
-// enabled, else Accrual::. These are the only entry points transactors call.
+// enabled AND the Vault's LEVersion (VaultHelpers::getVaultVersion) is
+// VaultVersion::CashBasis, else Accrual::. These are the only entry points
+// transactors call.
 AccountingDeltas
 loanOriginationDeltas(
     Rules const& rules,
+    SLE::const_ref vaultSle,
     Number const& principalRequested,
     Number const& interestDue);
 
 Number
-loanVaultExposure(Rules const& rules, SLE::ref loanSle);
+loanVaultExposure(Rules const& rules, SLE::const_ref vaultSle, SLE::const_ref loanSle);
 
 AccountingDeltas
-loanPaymentDeltas(Rules const& rules, LoanPaymentParts const& parts);
+loanPaymentDeltas(Rules const& rules, SLE::const_ref vaultSle, LoanPaymentParts const& parts);
 
 namespace detail {
 // These classes and functions should only be accessed by LendingHelper

include/xrpl/ledger/helpers/VaultHelpers.h

@@ -2,6 +2,7 @@
 
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/protocol/AccountID.h>
+#include <xrpl/protocol/Protocol.h>
 #include <xrpl/protocol/STAmount.h>
 #include <xrpl/protocol/STLedgerEntry.h>
 
@@ -107,4 +108,17 @@ sharesToAssetsWithdraw(
 [[nodiscard]] bool
 isSoleShareholder(ReadView const& view, AccountID const& account, SLE::const_ref issuance);
 
+/**
+ * Resolves a Vault's LEVersion, the single point every accounting touch
+ * point should call to determine which recognition model (accrual vs.
+ * cash-basis) a Vault uses. Vaults created before featureLendingProtocolV1_1
+ * activated never have sfLEVersion set, which resolves here to 0 (legacy).
+ *
+ * @param vault The vault SLE.
+ *
+ * @return The Vault's LEVersion, or 0 if the field is absent.
+ */
+[[nodiscard]] VaultVersion
+getVaultVersion(SLE::const_ref vault);
+
 }  // namespace xrpl

include/xrpl/protocol/Protocol.h

@@ -316,6 +316,18 @@ constexpr std::uint8_t kVaultDefaultIouScale = 6;
  */
 constexpr std::uint8_t kVaultMaximumIouScale = 18;
 
+/**
+ * Vault ledger-entry schema versions. Assigned to newly created
+ * Vaults once featureLendingProtocolV1_1 is enabled. Vaults created before
+ * activation are left without LEVersion (implicit legacy version 0,
+ * accrual-basis accounting).
+ */
+enum class VaultVersion : uint8_t {
+    Legacy = 0,
+    Invalid,
+    CashBasis,
+};
+
 /**
  * Maximum recursion depth for vault shares being put as an asset inside
  * another vault; counted from 0

include/xrpl/protocol/detail/ledger_entries.macro

@@ -505,6 +505,7 @@ LEDGER_ENTRY(ltVAULT, 0x0084, Vault, vault, ({
     {sfShareMPTID,           SoeRequired},
     {sfWithdrawalPolicy,     SoeRequired},
     {sfScale,                SoeDefault},
+    {sfLEVersion,            SoeDefault},
     // no SharesTotal ever (use MPTIssuance.sfOutstandingAmount)
     // no PermissionedDomainID ever (use MPTIssuance.sfDomainID)
 }))

include/xrpl/protocol/detail/sfields.macro

@@ -18,6 +18,7 @@ TYPED_SFIELD(sfMethod,                   UINT8,      2)
 TYPED_SFIELD(sfTransactionResult,        UINT8,      3)
 TYPED_SFIELD(sfScale,                    UINT8,      4)
 TYPED_SFIELD(sfAssetScale,               UINT8,      5)
+TYPED_SFIELD(sfLEVersion,                UINT8,      6)
 
 // 8-bit integers (uncommon)
 TYPED_SFIELD(sfTickSize,                 UINT8,     16)