refactor: pool.gno

pool/_RPC_dry.gno

@@ -58,9 +58,11 @@ func DrySwap(
 		feeGrowthGlobalX128 = pool.feeGrowthGlobal1X128
 	}
 
-	pool.slot0.unlocked = false
+	slot0 := pool.slot0
+	slot0.unlocked = false
+
 	cache := newSwapCache(feeProtocol, pool.liquidity)
-	state := pool.newSwapState(amountSpecified, feeGrowthGlobalX128, cache.liquidityStart) // TODO: feeGrowthGlobalX128.Clone() or NOT
+	state := newSwapState(amountSpecified.Clone(), feeGrowthGlobalX128.Clone(), cache.liquidityStart.Clone(), slot0)
 
 	exactInput := amountSpecified.Gt(i256.Zero())
 

pool/errors.gno

@@ -32,6 +32,7 @@ var (
 	errInvalidTickAndTickSpacing = errors.New("[GNOSWAP-POOL-022] invalid tick and tick spacing requested")
 	errInvalidAddress            = errors.New("[GNOSWAP-POOL-023] invalid address")
 	errInvalidTickRange          = errors.New("[GNOSWAP-POOL-024] tickLower is greater than tickUpper")
+  errUnderflow                 = errors.New("[GNOSWAP-POOL-025] underflow") // TODO: make as common error code
 )
 
 // addDetailToError adds detail to an error message