Merge remote-tracking branch 'origin/develop' into tapanito/transaction-invariant

include/xrpl/protocol/STAmount.h

@@ -42,8 +42,8 @@ private:
 public:
     using value_type = STAmount;
 
-    static int const cMinOffset = -96;
-    static int const cMaxOffset = 80;
+    constexpr static int cMinOffset = -96;
+    constexpr static int cMaxOffset = 80;
 
     // Maximum native value supported by the code
     constexpr static std::uint64_t cMinValue = 1'000'000'000'000'000ull;
@@ -734,6 +734,21 @@ canAdd(STAmount const& amt1, STAmount const& amt2);
 bool
 canSubtract(STAmount const& amt1, STAmount const& amt2);
 
+/** Get the scale of a Number for a given asset.
+ *
+ * "scale" is similar to "exponent", but from the perspective of STAmount, which has different rules
+ * and mantissa ranges for determining the exponent than Number.
+ *
+ * @param number The Number to get the scale of.
+ * @param asset The asset to use for determining the scale.
+ * @return The scale of this Number for the given asset.
+ */
+inline int
+scale(Number const& number, Asset const& asset)
+{
+    return STAmount{asset, number}.exponent();
+}
+
 }  // namespace xrpl
 
 //------------------------------------------------------------------------------

include/xrpl/tx/invariants/VaultInvariant.h

@@ -8,6 +8,7 @@
 #include <xrpl/protocol/STTx.h>
 #include <xrpl/protocol/TER.h>
 
+#include <optional>
 #include <unordered_map>
 #include <vector>
 
@@ -60,11 +61,23 @@ class ValidVault
         Shares static make(SLE const&);
     };
 
+public:
+    struct DeltaInfo final
+    {
+        Number delta = numZero;
+        std::optional<int> scale;
+
+        // Compute the delta between two Numbers, taking the coarsest scale
+        [[nodiscard]] static DeltaInfo
+        makeDelta(Number const& before, Number const& after, Asset const& asset);
+    };
+
+private:
     std::vector<Vault> afterVault_;
     std::vector<Shares> afterMPTs_;
     std::vector<Vault> beforeVault_;
     std::vector<Shares> beforeMPTs_;
-    std::unordered_map<uint256, Number> deltas_;
+    std::unordered_map<uint256, DeltaInfo> deltas_;
 
 public:
     void
@@ -72,6 +85,10 @@ public:
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
+
+    // Compute the coarsest scale required to represent all numbers
+    [[nodiscard]] static std::int32_t
+    computeCoarsestScale(std::vector<DeltaInfo> const& numbers);
 };
 
 }  // namespace xrpl

include/xrpl/tx/transactors/lending/LendingHelpers.h

@@ -171,7 +171,7 @@ getAssetsTotalScale(SLE::const_ref vaultSle)
 {
     if (!vaultSle)
         return Number::minExponent - 1;  // LCOV_EXCL_LINE
-    return STAmount{vaultSle->at(sfAsset), vaultSle->at(sfAssetsTotal)}.exponent();
+    return scale(vaultSle->at(sfAssetsTotal), vaultSle->at(sfAsset));
 }
 
 TER