Throw if dumping to ETH (#974)

* Throw if dumping to ETH

* ETH -> native asset

* Fix broken refactoring

src/tasks/dump.ts

@@ -625,6 +625,20 @@ async function transferSameTokenToReceiver(
   await receipt.wait();
 }
 
+export function assertNotBuyingNativeAsset(toToken: string | undefined) {
+  // This function checks that toToken is not the native asset (e.g., ETH).
+  // Technically, this script was built to support selling ETH. However, there
+  // are two requirement from the backend for it to work:
+  // 1. Sending native assets to smart contracts should be supported. At the
+  //    time of writing, this returns an error when creating the order.
+  // 2. Selling wrapped native assets for their unwrapped counterpart should be
+  //    supported. It currently returns an error about the fact that the token
+  //    is the same.
+  if ([undefined, BUY_ETH_ADDRESS].includes(toToken)) {
+    throw new Error("Receiving native asset is not supported yet.");
+  }
+}
+
 interface DumpInput {
   validity: number;
   maxFeePercent: number;
@@ -661,6 +675,9 @@ export async function dump({
 }: DumpInput): Promise<void> {
   const { ethers } = hre;
 
+  // TODO: remove once native asset orders are fully supported.
+  assertNotBuyingNativeAsset(toTokenAddress);
+
   const [chainId, vaultRelayer] = await Promise.all([
     ethers.provider.getNetwork().then((n) => n.chainId),
     (await settlement.vaultRelayer()) as string,

src/tasks/withdrawService.ts

@@ -11,7 +11,11 @@ import { HardhatRuntimeEnvironment } from "hardhat/types";
 import { BUY_ETH_ADDRESS } from "../ts";
 import { Api, Environment } from "../ts/api";
 
-import { dump, MAX_ORDER_VALIDITY_SECONDS } from "./dump";
+import {
+  assertNotBuyingNativeAsset,
+  dump,
+  MAX_ORDER_VALIDITY_SECONDS,
+} from "./dump";
 import {
   getDeployedContract,
   isSupportedNetwork,
@@ -544,6 +548,9 @@ const setupWithdrawServiceTask: () => void = () =>
         },
         hre: HardhatRuntimeEnvironment,
       ) => {
+        // TODO: remove once native asset orders are fully supported.
+        assertNotBuyingNativeAsset(toToken);
+
         const state = await getState(stateFilePath);
         console.debug(`Initial state: ${JSON.stringify(state)}`);
         const network = hre.network.name;