Fix adjustAmountsByLPTokens()

gregtatcam · May 4, 2024 · 0e3b555 · 0e3b555
1 parent c31ff5b
commit 0e3b555
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Showing 5 changed files with 330 additions and 186 deletions.
diff --git a/src/ripple/app/misc/impl/AMMHelpers.cpp b/src/ripple/app/misc/impl/AMMHelpers.cpp
@@ -178,18 +178,31 @@ adjustAmountsByLPTokens(
                 lpTokensActual);
         }
 
+        bool const ammRoundingEnabled = [&]() {
+            if (auto const& rules = getCurrentTransactionRules();
+                rules && rules->enabled(fixAMMRounding))
+                return true;
+            return false;
+        }();
+
         // Single trade
         auto const amountActual = [&]() {
             if (isDeposit)
                 return ammAssetIn(
                     amountBalance, lptAMMBalance, lpTokensActual, tfee);
-            else
+            else if (!ammRoundingEnabled)
                 return withdrawByTokens(
                     amountBalance, lptAMMBalance, lpTokens, tfee);
+            else
+                return withdrawByTokens(
+                    amountBalance, lptAMMBalance, lpTokensActual, tfee);
         }();
-        return amountActual < amount
-            ? std::make_tuple(amountActual, std::nullopt, lpTokensActual)
-            : std::make_tuple(amount, std::nullopt, lpTokensActual);
+        if (!ammRoundingEnabled)
+            return amountActual < amount
+                ? std::make_tuple(amountActual, std::nullopt, lpTokensActual)
+                : std::make_tuple(amount, std::nullopt, lpTokensActual);
+        else
+            return std::make_tuple(amountActual, std::nullopt, lpTokensActual);
     }
 
     assert(lpTokensActual == lpTokens);

diff --git a/src/test/app/AMMExtended_test.cpp b/src/test/app/AMMExtended_test.cpp
@@ -233,7 +233,7 @@ struct AMMExtended_test : public jtx::AMMTest
                 {{XRP(10'100), USD(10'000)}},
                 0,
                 std::nullopt,
-                tweakedFeatures);
+                {tweakedFeatures});
 
             // Immediate or Cancel - cross as much as possible
             // and add nothing on the books.
@@ -257,7 +257,7 @@ struct AMMExtended_test : public jtx::AMMTest
                 {{XRP(10'100), USD(10'000)}},
                 0,
                 std::nullopt,
-                tweakedFeatures);
+                {tweakedFeatures});
 
             // tfPassive -- place the offer without crossing it.
             testAMM(
@@ -274,7 +274,7 @@ struct AMMExtended_test : public jtx::AMMTest
                 {{XRP(10'100), USD(10'000)}},
                 0,
                 std::nullopt,
-                tweakedFeatures);
+                {tweakedFeatures});
 
             // tfPassive -- cross only offers of better quality.
             testAMM(
@@ -296,7 +296,7 @@ struct AMMExtended_test : public jtx::AMMTest
                 {{XRP(11'000), USD(9'000)}},
                 0,
                 std::nullopt,
-                tweakedFeatures);
+                {tweakedFeatures});
         }
     }
 
@@ -430,7 +430,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(10'000), USD(10'000)}},
             0,
             std::nullopt,
-            features);
+            {features});
     }
 
     void
@@ -453,7 +453,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(10'000), USD(10'100)}},
             0,
             std::nullopt,
-            features);
+            {features});
     }
 
     void
@@ -477,7 +477,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(10'100), USD(10'000)}},
             0,
             std::nullopt,
-            features);
+            {features});
     }
 
     void
@@ -643,7 +643,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(9'900), USD(10'100)}},
             0,
             std::nullopt,
-            features);
+            {features});
     }
 
     void
@@ -952,7 +952,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(10'000), USD(10'100)}},
             0,
             std::nullopt,
-            features);
+            {features});
 
         // Reverse the order, so the offer in the books is to sell XRP
         // in return for USD.
@@ -973,7 +973,7 @@ struct AMMExtended_test : public jtx::AMMTest
             {{XRP(10'100), USD(10'000)}},
             0,
             std::nullopt,
-            features);
+            {features});
 
         {
             // Bridged crossing.