Fix pool swap zero amount result (#1067)

* Fix pool swap zero amount result Signed-off-by: Anthony Fieroni <bvbfan@abv.bg> * Prevent divide by zero Signed-off-by: Anthony Fieroni <bvbfan@abv.bg>
DeFiCh · Jan 26, 2022 · 4c2044a · 4c2044a
1 parent cb25b76
commit 4c2044a
Showing 1 changed file with 10 additions and 12 deletions.
diff --git a/src/masternodes/mn_checks.cpp b/src/masternodes/mn_checks.cpp
@@ -3761,7 +3761,6 @@ std::vector<std::vector<DCT_ID>> CPoolSwap::CalculatePoolPaths(CCustomCSView& vi
 // testOnly is only meant for one-off tests per well defined view.
 Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, bool testOnly) {
 
-    CTokenAmount swapAmountResult{{},0};
     Res poolResult = Res::Ok();
 
     // No composite swap allowed before Fort Canning
@@ -3792,6 +3791,9 @@ Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, boo
         mnview.Flush();
     }
 
+    // Set amount to be swapped in pool
+    CTokenAmount swapAmountResult{obj.idTokenFrom, obj.amountFrom};
+
     for (size_t i{0}; i < poolIDs.size(); ++i) {
 
         // Also used to generate pool specific error messages for RPC users
@@ -3810,17 +3812,11 @@ Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, boo
             }
         }
 
-        // Set amount to be swapped in pool
-        CTokenAmount swapAmount{obj.idTokenFrom, obj.amountFrom};
-
-        // If set use amount from previous loop
-        if (swapAmountResult.nValue != 0) {
-            swapAmount = swapAmountResult;
-        }
-
         // Check if last pool swap
         bool lastSwap = i + 1 == poolIDs.size();
 
+        const auto swapAmount = swapAmountResult;
+
         if (height >= static_cast<uint32_t>(Params().GetConsensus().FortCanningHillHeight) && lastSwap) {
             if (obj.idTokenTo == swapAmount.nTokenId) {
                 return Res::Err("Final swap should have idTokenTo as destination, not source");
@@ -3900,9 +3896,11 @@ Res CPoolSwap::ExecuteSwap(CCustomCSView& view, std::vector<DCT_ID> poolIDs, boo
 
     // Reject if price paid post-swap above max price provided
     if (height >= Params().GetConsensus().FortCanningHeight && obj.maxPrice != POOLPRICE_MAX) {
-        const CAmount userMaxPrice = obj.maxPrice.integer * COIN + obj.maxPrice.fraction;
-        if (arith_uint256(obj.amountFrom) * COIN / swapAmountResult.nValue > userMaxPrice) {
-            return Res::Err("Price is higher than indicated.");
+        if (swapAmountResult.nValue != 0) {
+            const auto userMaxPrice = arith_uint256(obj.maxPrice.integer) * COIN + obj.maxPrice.fraction;
+            if (arith_uint256(obj.amountFrom) * COIN / swapAmountResult.nValue > userMaxPrice) {
+                return Res::Err("Price is higher than indicated.");
+            }
         }
     }