refactor: Centralise BigNumber import (#1820)

Stop depending directly on ethers for this, such that it should be
easier to eventually shift away from ethers v5.

.eslintrc.js

@@ -38,6 +38,13 @@ module.exports = {
     "no-duplicate-imports": "error",
     "@typescript-eslint/no-floating-promises": ["error"],
     "@typescript-eslint/no-misused-promises": ["error", { checksVoidReturn: false }],
+    "no-restricted-imports": [
+      "error",
+      {
+        patterns: [{ group: ["@ethersproject/bignumber"], message: "Use 'src/utils/BNUtils' instead" }],
+        paths: [{ name: "ethers", importNames: ["BigNumber"], message: "Use 'src/utils/BNUtils' instead" }],
+      },
+    ],
   },
   settings: {
     node: {

package.json

@@ -20,6 +20,7 @@
     "@ethersproject/abi": "^5.7.0",
     "@ethersproject/abstract-provider": "^5.7.0",
     "@ethersproject/abstract-signer": "^5.7.0",
+    "@ethersproject/bignumber": "^5.7.0",
     "@google-cloud/kms": "^3.6.0",
     "@google-cloud/storage": "^6.10.1",
     "@maticnetwork/maticjs": "^3.6.0",

scripts/hubpool.ts

@@ -1,14 +1,12 @@
 import minimist from "minimist";
 import { WETH9__factory as WETH9 } from "@across-protocol/contracts";
 import { constants as sdkConsts } from "@across-protocol/sdk";
-import { BigNumber, ethers, Signer } from "ethers";
+import { ethers, Signer } from "ethers";
 import { config } from "dotenv";
-import { getNetworkName, getSigner } from "../src/utils";
+import { BigNumber, bnOne, bnUint256Max, formatEther, formatUnits, getNetworkName, getSigner } from "../src/utils";
 import * as utils from "./utils";
 
 const { PROTOCOL_DEFAULT_CHAIN_ID_INDICES } = sdkConsts;
-const { MaxUint256, One: bnOne } = ethers.constants;
-const { formatEther, formatUnits } = ethers.utils;
 
 const { NODE_SUCCESS, NODE_INPUT_ERR, NODE_APP_ERR } = utils;
 
@@ -99,7 +97,7 @@ async function dispute(args: Record<string, number | string>, signer: Signer): P
 
   if (allowance.lt(bondAmount)) {
     console.log(`Approving ${network} HubPool @ ${hubPool.address} to transfer ${symbol}.`);
-    const approval = await bondToken.connect(signer).approve(hubPool.address, MaxUint256);
+    const approval = await bondToken.connect(signer).approve(hubPool.address, bnUint256Max);
     console.log(`Approval: ${approval.hash}...`);
     await approval.wait();
   }

src/adapter/bridges/UsdcCCTPBridge.ts

@@ -1,7 +1,7 @@
-import { BigNumber, Contract, Signer } from "ethers";
+import { Contract, Signer } from "ethers";
 import { CONTRACT_ADDRESSES, chainIdsToCctpDomains } from "../../common";
 import { BridgeTransactionDetails, BaseBridgeAdapter, BridgeEvents } from "./BaseBridgeAdapter";
-import { EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP, compareAddressesSimple, assert } from "../../utils";
+import { BigNumber, EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP, compareAddressesSimple, assert } from "../../utils";
 import { processEvent } from "../utils";
 import { cctpAddressToBytes32, retrieveOutstandingCCTPBridgeUSDCTransfers } from "../../utils/CCTPUtils";
 

src/adapter/bridges/UsdcTokenSplitterBridge.ts

@@ -1,8 +1,8 @@
-import { BigNumber, Signer } from "ethers";
+import { Signer } from "ethers";
 import { CONTRACT_ADDRESSES, CANONICAL_BRIDGE } from "../../common";
 import { UsdcCCTPBridge } from "./UsdcCCTPBridge";
 import { BridgeTransactionDetails, BaseBridgeAdapter, BridgeEvents } from "./BaseBridgeAdapter";
-import { EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP, compareAddressesSimple, assert } from "../../utils";
+import { BigNumber, EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP, compareAddressesSimple, assert } from "../../utils";
 
 export class UsdcTokenSplitterBridge extends BaseBridgeAdapter {
   protected cctpBridge: BaseBridgeAdapter;

src/adapter/bridges/ZKSyncBridge.ts

@@ -176,7 +176,7 @@ export class ZKSyncBridge extends BaseBridgeAdapter {
     return l2Gas;
   }
 
-  protected getMailboxContract() {
+  protected getMailboxContract(): Contract {
     return this.zkSyncMailbox;
   }
 }

src/adapter/utils.ts

@@ -1,6 +1,7 @@
-import { BigNumber, Event } from "ethers";
+import { Event } from "ethers";
 import { TOKEN_APPROVALS_TO_FIRST_ZERO } from "../common";
 import {
+  BigNumber,
   spreadEventWithBlockNumber,
   toBN,
   MAX_SAFE_ALLOWANCE,

src/clients/InventoryClient.ts

@@ -1,4 +1,3 @@
-import { utils as ethersUtils } from "ethers";
 import { constants, utils as sdkUtils } from "@across-protocol/sdk";
 import WETH_ABI from "../common/abi/Weth.json";
 import {
@@ -10,6 +9,7 @@ import {
   createFormatFunction,
   blockExplorerLink,
   Contract,
+  formatUnits,
   runTransaction,
   isDefined,
   DefaultLogLevels,
@@ -577,9 +577,9 @@ export class InventoryClient {
           cumulativeVirtualBalance,
           cumulativeVirtualBalanceWithShortfall,
           cumulativeVirtualBalanceWithShortfallPostRefunds,
-          targetPct: ethersUtils.formatUnits(tokenConfig.targetPct, 18),
-          targetOverage: ethersUtils.formatUnits(targetOverageBuffer, 18),
-          effectiveTargetPct: ethersUtils.formatUnits(effectiveTargetPct, 18),
+          targetPct: formatUnits(tokenConfig.targetPct, 18),
+          targetOverage: formatUnits(targetOverageBuffer, 18),
+          effectiveTargetPct: formatUnits(effectiveTargetPct, 18),
           expectedPostRelayAllocation,
           chainsToEvaluate,
         }

src/clients/MultiCallerClient.ts

@@ -1,7 +1,7 @@
 import { utils as sdkUtils } from "@across-protocol/sdk";
-import { BigNumber } from "ethers";
 import { DEFAULT_MULTICALL_CHUNK_SIZE, Multicall2Call } from "../common";
 import {
+  BigNumber,
   winston,
   bnZero,
   getNetworkName,

src/clients/bridges/op-stack/OpStackAdapter.ts

@@ -5,10 +5,10 @@ import {
   Contract,
   BigNumber,
   BigNumberish,
+  bnZero,
   TransactionResponse,
   Event,
   checkAddressChecksum,
-  ethers,
   spreadEventWithBlockNumber,
   assign,
   winston,
@@ -146,7 +146,7 @@ export class OpStackAdapter extends BaseAdapter {
       method,
       args,
       gasLimitMultiplier,
-      ethers.constants.Zero,
+      bnZero,
       simMode
     );
   }

src/clients/bridges/op-stack/UsdcCCTPBridge.ts

@@ -1,7 +1,7 @@
-import { BigNumber, Contract, Signer } from "ethers";
+import { Contract, Signer } from "ethers";
 import { CONTRACT_ADDRESSES, chainIdsToCctpDomains } from "../../../common";
 import { BridgeTransactionDetails, OpStackBridge, OpStackEvents } from "./OpStackBridgeInterface";
-import { EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP } from "../../../utils";
+import { BigNumber, EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP } from "../../../utils";
 import { cctpAddressToBytes32, retrieveOutstandingCCTPBridgeUSDCTransfers } from "../../../utils/CCTPUtils";
 
 export class UsdcCCTPBridge extends OpStackBridge {

src/clients/bridges/op-stack/UsdcTokenSplitterBridge.ts

@@ -1,7 +1,14 @@
-import { BigNumber, Signer } from "ethers";
+import { Signer } from "ethers";
 import { DefaultERC20Bridge } from "./DefaultErc20Bridge";
 import { UsdcCCTPBridge } from "./UsdcCCTPBridge";
-import { EventSearchConfig, Provider, TOKEN_SYMBOLS_MAP, assert, compareAddressesSimple } from "../../../utils";
+import {
+  BigNumber,
+  EventSearchConfig,
+  Provider,
+  TOKEN_SYMBOLS_MAP,
+  assert,
+  compareAddressesSimple,
+} from "../../../utils";
 import { BridgeTransactionDetails, OpStackBridge, OpStackEvents } from "./OpStackBridgeInterface";
 import { CONTRACT_ADDRESSES } from "../../../common";
 

src/clients/bridges/utils.ts

@@ -1,6 +1,7 @@
-import { BigNumber, Contract, Event } from "ethers";
+import { Contract, Event } from "ethers";
 import { TOKEN_APPROVALS_TO_FIRST_ZERO } from "../../common";
 import {
+  BigNumber,
   MAX_SAFE_ALLOWANCE,
   blockExplorerLink,
   bnZero,

src/finalizer/index.ts

@@ -1,6 +1,6 @@
 import { utils as sdkUtils } from "@across-protocol/sdk";
 import assert from "assert";
-import { BigNumber, Contract, constants } from "ethers";
+import { Contract } from "ethers";
 import { getAddress } from "ethers/lib/utils";
 import { groupBy, uniq } from "lodash";
 import { AugmentedTransaction, HubPoolClient, MultiCallerClient, TransactionClient } from "../clients";
@@ -17,6 +17,8 @@ import {
 import { DataworkerConfig } from "../dataworker/DataworkerConfig";
 import { SpokePoolClientsByChain } from "../interfaces";
 import {
+  BigNumber,
+  bnZero,
   Signer,
   blockExplorerLink,
   config,
@@ -253,7 +255,7 @@ export async function finalize(
 
   const txnClient = new TransactionClient(logger);
 
-  let gasEstimation = constants.Zero;
+  let gasEstimation = bnZero;
   const batchGasLimit = BigNumber.from(10_000_000);
   // @dev To avoid running into block gas limit in case the # of finalizations gets too high, keep a running
   // counter of the approximate gas estimation and cut off the list of finalizations if it gets too high.

src/interfaces/InventoryManagement.ts

@@ -1,5 +1,5 @@
-import { BigNumber, utils as ethersUtils } from "ethers";
-import { TOKEN_SYMBOLS_MAP } from "../utils";
+import { utils as ethersUtils } from "ethers";
+import { BigNumber, TOKEN_SYMBOLS_MAP } from "../utils";
 
 export type TokenBalanceConfig = {
   targetOverageBuffer: BigNumber; // Max multiplier for targetPct, to give flexibility in repayment chain selection.

src/interfaces/Report.ts

@@ -1,4 +1,4 @@
-import { BigNumber } from "ethers";
+import { BigNumber } from "../utils";
 
 export enum BundleAction {
   PROPOSED = "proposed",

src/interfaces/Token.ts

@@ -1,4 +1,4 @@
-import { BigNumber } from "ethers";
+import { BigNumber } from "../utils";
 import { SortableEvent } from ".";
 
 export interface TokenTransfer extends SortableEvent {

src/interfaces/index.ts

@@ -1,5 +1,5 @@
-import { BigNumber } from "ethers";
 import { interfaces } from "@across-protocol/sdk";
+import { BigNumber } from "../utils";
 
 export * from "./InventoryManagement";
 export * from "./SpokePool";

src/monitor/Monitor.ts

@@ -17,16 +17,17 @@ import {
   convertFromWei,
   createFormatFunction,
   ERC20,
-  ethers,
   fillStatusArray,
   blockExplorerLink,
   blockExplorerLinks,
+  formatUnits,
   getNativeTokenAddressForChain,
   getGasPrice,
   getNativeTokenSymbol,
   getNetworkName,
   getUnfilledDeposits,
   mapAsync,
+  parseUnits,
   providers,
   toBN,
   toBNWei,
@@ -42,11 +43,9 @@ import { MonitorClients, updateMonitorClients } from "./MonitorClientHelper";
 import { MonitorConfig } from "./MonitorConfig";
 import { CombinedRefunds } from "../dataworker/DataworkerUtils";
 
-export const REBALANCE_FINALIZE_GRACE_PERIOD = process.env.REBALANCE_FINALIZE_GRACE_PERIOD
-  ? Number(process.env.REBALANCE_FINALIZE_GRACE_PERIOD)
-  : 60 * 60;
 // 60 minutes, which is the length of the challenge window, so if a rebalance takes longer than this to finalize,
 // then its finalizing after the subsequent challenge period has started, which is sub-optimal.
+export const REBALANCE_FINALIZE_GRACE_PERIOD = Number(process.env.REBALANCE_FINALIZE_GRACE_PERIOD ?? 60 * 60);
 
 // bundle frequency.
 export const ALL_CHAINS_NAME = "All chains";
@@ -381,8 +380,8 @@ export class Monitor {
           token,
           account,
           currentBalance: balances[i].toString(),
-          warnThreshold: ethers.utils.parseUnits(warnThreshold.toString(), decimalValues[i]),
-          errorThreshold: ethers.utils.parseUnits(errorThreshold.toString(), decimalValues[i]),
+          warnThreshold: parseUnits(warnThreshold.toString(), decimalValues[i]),
+          errorThreshold: parseUnits(errorThreshold.toString(), decimalValues[i]),
         };
       }),
     });
@@ -397,10 +396,10 @@ export class Monitor {
             const decimals = decimalValues[i];
             let trippedThreshold: { level: "warn" | "error"; threshold: number } | null = null;
 
-            if (warnThreshold !== null && balance.lt(ethers.utils.parseUnits(warnThreshold.toString(), decimals))) {
+            if (warnThreshold !== null && balance.lt(parseUnits(warnThreshold.toString(), decimals))) {
               trippedThreshold = { level: "warn", threshold: warnThreshold };
             }
-            if (errorThreshold !== null && balance.lt(ethers.utils.parseUnits(errorThreshold.toString(), decimals))) {
+            if (errorThreshold !== null && balance.lt(parseUnits(errorThreshold.toString(), decimals))) {
               trippedThreshold = { level: "error", threshold: errorThreshold };
             }
             if (trippedThreshold !== null) {
@@ -418,7 +417,7 @@ export class Monitor {
                 text: `  ${getNetworkName(chainId)} ${symbol} balance for ${blockExplorerLink(
                   account,
                   chainId
-                )} is ${ethers.utils.formatUnits(balance, decimals)}. Threshold: ${trippedThreshold.threshold}`,
+                )} is ${formatUnits(balance, decimals)}. Threshold: ${trippedThreshold.threshold}`,
               };
             }
           }
@@ -456,7 +455,7 @@ export class Monitor {
           token,
           account,
           currentBalance: currentBalances[i].toString(),
-          target: ethers.utils.parseUnits(target.toString(), decimalValues[i]),
+          target: parseUnits(target.toString(), decimalValues[i]),
         };
       }),
     });
@@ -467,11 +466,11 @@ export class Monitor {
       refillEnabledBalances.map(async ({ chainId, isHubPool, token, account, target, trigger }, i) => {
         const currentBalance = currentBalances[i];
         const decimals = decimalValues[i];
-        const balanceTrigger = ethers.utils.parseUnits(trigger.toString(), decimals);
+        const balanceTrigger = parseUnits(trigger.toString(), decimals);
         const isBelowTrigger = currentBalance.lte(balanceTrigger);
         if (isBelowTrigger) {
           // Fill balance back to target, not trigger.
-          const balanceTarget = ethers.utils.parseUnits(target.toString(), decimals);
+          const balanceTarget = parseUnits(target.toString(), decimals);
           const deficit = balanceTarget.sub(currentBalance);
           let canRefill = await this.balanceAllocator.requestBalanceAllocation(
             chainId,
@@ -541,7 +540,7 @@ export class Monitor {
                 method: "loadEthForL2Calls",
                 args: [],
                 message: "Reloaded ETH in HubPool 🫡!",
-                mrkdwn: `Loaded ${ethers.utils.formatUnits(deficit, decimals)} ETH from ${signerAddress}.`,
+                mrkdwn: `Loaded ${formatUnits(deficit, decimals)} ETH from ${signerAddress}.`,
                 value: deficit,
               });
             } else {
@@ -554,7 +553,7 @@ export class Monitor {
               const receipt = await tx.wait();
               this.logger.info({
                 at: "Monitor#refillBalances",
-                message: `Reloaded ${ethers.utils.formatUnits(
+                message: `Reloaded ${formatUnits(
                   deficit,
                   decimals
                 )} ${nativeSymbolForChain} for ${account} from ${signerAddress} 🫡!`,

src/utils/BNUtils.ts

@@ -1,4 +1,8 @@
-import { BigNumber } from "ethers";
+// eslint-disable-next-line no-restricted-imports
+import { BigNumber } from "@ethersproject/bignumber";
+
+// eslint-disable-next-line no-restricted-imports
+export * from "@ethersproject/bignumber";
 
 export function bnComparatorDescending(a: BigNumber, b: BigNumber): -1 | 0 | 1 {
   if (b.gt(a)) {

src/utils/CCTPUtils.ts

@@ -1,9 +1,10 @@
 import { utils } from "@across-protocol/sdk";
 import { TransactionReceipt } from "@ethersproject/abstract-provider";
 import axios from "axios";
-import { BigNumber, ethers } from "ethers";
+import { ethers } from "ethers";
 import { CONTRACT_ADDRESSES, chainIdsToCctpDomains } from "../common";
 import { EventSearchConfig, paginatedEventQuery } from "./EventUtils";
+import { BigNumber } from "./BNUtils";
 import { bnZero, compareAddressesSimple } from "./SDKUtils";
 import { isDefined } from "./TypeGuards";
 import { getProvider } from "./ProviderUtils";

src/utils/SDKUtils.ts

@@ -27,7 +27,10 @@ export const {
   fillStatusArray,
   fixedPointAdjustment,
   forEachAsync,
+  formatEther,
+  formatUnits,
   mapAsync,
+  parseUnits,
   filterAsync,
   toBN,
   bnToHex,

src/utils/TokenUtils.ts

@@ -1,7 +1,9 @@
+import { TOKEN_SYMBOLS_MAP } from "@across-protocol/constants";
 import { constants, utils } from "@across-protocol/sdk";
 import { CONTRACT_ADDRESSES } from "../common";
-import { BigNumberish, utils as ethersUtils } from "ethers";
-import { TOKEN_SYMBOLS_MAP } from "@across-protocol/constants";
+import { BigNumberish } from "./BNUtils";
+import { formatUnits } from "./SDKUtils";
+
 const { ZERO_ADDRESS } = constants;
 
 export const { fetchTokenInfo, getL2TokenAddresses } = utils;
@@ -18,5 +20,5 @@ export function getNativeTokenAddressForChain(chainId: number): string {
  */
 export function formatUnitsForToken(symbol: string, amount: BigNumberish): string {
   const decimals = (TOKEN_SYMBOLS_MAP[symbol]?.decimals as number) ?? 18;
-  return ethersUtils.formatUnits(amount, decimals);
+  return formatUnits(amount, decimals);
 }

src/utils/TransactionUtils.ts

@@ -221,6 +221,6 @@ export function getTarget(targetAddress: string):
   }
 }
 
-function scaleByNumber(amount: ethers.BigNumber, scaling: number) {
+function scaleByNumber(amount: BigNumber, scaling: number) {
   return amount.mul(toBNWei(scaling)).div(fixedPoint);
 }