Fix gas estimation for roflmarket.InstanceTopUp

Author: ptrus

cmd/common/transaction.go

@@ -265,8 +265,15 @@ func PrepareParatimeTransaction(ctx context.Context, npa *NPASelection, account
 			return 0, nil, "", fmt.Errorf("failed to estimate gas: %w", err)
 		}
 
-		// Inflate the estimate by 20% for good measure.
-		gas = (120 * gas) / 100
+		// Inflate the estimate for good measure. Some methods need a higher
+		// buffer due to gas estimation returning early without simulating
+		// storage operations.
+		multiplier := uint64(120) // Default 20%.
+		switch tx.Call.Method {
+		case "roflmarket.InstanceTopUp":
+			multiplier = 150 // 50%.
+		}
+		gas = (multiplier * gas) / 100
 	}
 
 	// Compute fee.