Add zero tokens variant

gregtatcam · Nov 11, 2024 · 1ef2ce2 · 1ef2ce2
1 parent 71ec9cb
commit 1ef2ce2
Showing 1 changed file with 29 additions and 8 deletions.
diff --git a/src/xrpld/app/tx/detail/InvariantCheck.cpp b/src/xrpld/app/tx/detail/InvariantCheck.cpp
@@ -1204,11 +1204,19 @@ ValidAMM::finalize(
             NumberRoundModeGuard g(Number::upward);
             auto const res = root2(amount * amount2);
             if (res >= *lptAMMBalance_)
-                return true;
+            {
+                if (*lptAMMBalance_ > beast::zero)
+                    return true;
+                // last withdraw may have resulted in an empty AMM
+                if (txType == ttAMM_WITHDRAW &&
+                    *lptAMMBalance_ == beast::zero && amount == beast::zero &&
+                    amount2 == beast::zero)
+                    return true;
+            }
 
             std::string const txt =
                 txType == ttAMM_DEPOSIT ? "AMMDeposit" : "AMMWithdraw";
-            JLOG(j.trace())
+            JLOG(j.error())
                 << txt << " invariant failed: " << amount << " " << amount2
                 << " " << res << " " << lptAMMBalance_->getText();
             return false;
@@ -1222,11 +1230,12 @@ ValidAMM::finalize(
                 tx[sfAmount2].get<Issue>(),
                 fhIGNORE_FREEZE,
                 j);
-            if (ammLPTokens(amount, amount2, lptAMMBalance_->issue()) ==
-                *lptAMMBalance_)
+            if (*lptAMMBalance_ > beast::zero &&
+                ammLPTokens(amount, amount2, lptAMMBalance_->issue()) ==
+                    *lptAMMBalance_)
                 return true;
 
-            JLOG(j.trace()) << "AMMCreate invariant failed: " << amount << " "
+            JLOG(j.error()) << "AMMCreate invariant failed: " << amount << " "
                             << amount2 << " " << *lptAMMBalance_;
             return false;
         }
@@ -1241,10 +1250,22 @@ ValidAMM::finalize(
                 if (auto const root = _view.read(keylet::account(k));
                     root && root->isFieldPresent(sfAMMID))
                 {
+                    if (auto const amm =
+                            _view.read(keylet::amm((*root)[sfAMMID]));
+                        amm && (*amm)[sfLPTokenBalance] <= beast::zero)
+                    {
+                        // LCOV_EXCL_START
+                        JLOG(j.error())
+                            << "AMM swap invariant failed: invalid token "
+                               "balance "
+                            << to_string(k) << " " << (*amm)[sfLPTokenBalance];
+                        return false;
+                        // LCOV_EXCL_STOP
+                    }
                     // AMM must have two balances - one for each pool side
                     if (!balanceAfter_.contains(k) || v.size() != 2)
                     {
-                        JLOG(j.trace())
+                        JLOG(j.error())
                             << "AMM swap invariant failed: inconsistent assets "
                             << to_string(k) << " " << v.size();
                         return false;
@@ -1255,7 +1276,7 @@ ValidAMM::finalize(
                     if (!balanceAfter_[k].contains(asset) ||
                         !balanceAfter_[k].contains(asset2))
                     {
-                        JLOG(j.trace())
+                        JLOG(j.error())
                             << "AMM swap invariant failed: inconsistent assets "
                             << to_string(k) << " " << asset << " " << asset2;
                         return false;
@@ -1269,7 +1290,7 @@ ValidAMM::finalize(
                             balanceAfter_[k][asset] * balanceAfter_[k][asset2];
                         if (productAfter < productBefore)
                         {
-                            JLOG(j.trace())
+                            JLOG(j.error())
                                 << "AMM swap invariant failed: old balances "
                                 << balanceBefore_[k][asset].getText() << " "
                                 << balanceBefore_[k][asset2].getText()