Add additional USDT approve transaction to account for must-reset-to-0 behavior

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- added: Add additional `approve` transaction for tokens that require allowances to be 0 before updating, like USDT on Ethereum
+- changed: Support multiple pre transactions
+
 ## 2.38.0 (2025-11-03)
 
 - changed: (Letsexchange) Disable ZEC swaps completely

src/swap/defi/defiUtils.ts

@@ -1,7 +1,13 @@
 import { asMaybe, asObject, asString } from 'cleaners'
-import { EdgeCurrencyConfig, EdgeToken } from 'edge-core-js/types'
+import {
+  EdgeCurrencyConfig,
+  EdgeSpendInfo,
+  EdgeToken,
+  EdgeTransaction
+} from 'edge-core-js/types'
 import { ethers } from 'ethers'
 
+import { EdgeSwapRequestPlugin } from '../types'
 import abi from './abi/THORCHAIN_SWAP_ABI'
 import erc20Abi from './abi/UNISWAP_V2_ERC20_ABI'
 
@@ -75,28 +81,90 @@ const getEvmCheckSumAddress = (assetAddress: string): string => {
   return ethers.utils.getAddress(assetAddress.toLowerCase())
 }
 
-export const getEvmApprovalData = async (params: {
+export const getEvmApprovalData = ({
+  contractAddress,
+  nativeAmount
+}: {
   contractAddress: string
-  assetAddress: string
   nativeAmount: string
-}): Promise<string | undefined> => {
-  const { contractAddress, assetAddress, nativeAmount } = params
-  const contract = new ethers.Contract(
-    assetAddress,
-    erc20Abi,
-    ethers.providers.getDefaultProvider()
-  )
-
-  const bnNativeAmount = ethers.BigNumber.from(nativeAmount)
-  const approveTx = await contract.populateTransaction.approve(
+}): string => {
+  const iface = new ethers.utils.Interface(erc20Abi)
+  const data = iface.encodeFunctionData('approve', [
     contractAddress,
-    bnNativeAmount,
-    {
-      gasLimit: '500000',
-      gasPrice: '20'
+    nativeAmount
+  ])
+  return data
+}
+
+const NON_STANDARD_APPROVAL_TOKENS: { [pluginId: string]: string[] } = {
+  ethereum: ['dac17f958d2ee523a2206206994597c13d831ec7' /* USDT */]
+}
+
+export const createEvmApprovalEdgeTransactions = async ({
+  request,
+  approvalAmount,
+  tokenContractAddress,
+  recipientAddress,
+  networkFeeOption,
+  customNetworkFee
+}: {
+  request: EdgeSwapRequestPlugin
+  approvalAmount: string
+  tokenContractAddress: string
+  recipientAddress: string
+  networkFeeOption?: EdgeSpendInfo['networkFeeOption']
+  customNetworkFee?: EdgeSpendInfo['customNetworkFee']
+}): Promise<EdgeTransaction[]> => {
+  const out: EdgeTransaction[] = []
+
+  const createApprovalTx = async (amount: string): Promise<EdgeTransaction> => {
+    const approvalData = getEvmApprovalData({
+      contractAddress: tokenContractAddress,
+      nativeAmount: amount
+    })
+    const spendInfo: EdgeSpendInfo = {
+      tokenId: null,
+      memos: [{ type: 'hex', value: approvalData.replace(/^0x/, '') }],
+      spendTargets: [
+        {
+          nativeAmount: '0',
+          publicAddress: tokenContractAddress
+        }
+      ],
+      networkFeeOption,
+      customNetworkFee,
+      assetAction: {
+        assetActionType: 'tokenApproval'
+      },
+      savedAction: {
+        actionType: 'tokenApproval',
+        tokenApproved: {
+          pluginId: request.fromWallet.currencyInfo.pluginId,
+          tokenId: request.fromTokenId,
+          nativeAmount: amount
+        },
+        tokenContractAddress: tokenContractAddress,
+        contractAddress: recipientAddress
+      }
     }
-  )
-  return approveTx.data != null ? approveTx.data.replace(/^0x/, '') : undefined
+    return await request.fromWallet.makeSpend(spendInfo)
+  }
+
+  // If the token requires resetting allowance to 0, create a pre-tx to do so
+  if (
+    request.fromTokenId != null &&
+    NON_STANDARD_APPROVAL_TOKENS[
+      request.fromWallet.currencyInfo.pluginId
+    ].includes(request.fromTokenId)
+  ) {
+    const preTx = await createApprovalTx('0')
+    out.push(preTx)
+  }
+
+  const preTx = await createApprovalTx(approvalAmount)
+  out.push(preTx)
+
+  return out
 }
 
 export const getDepositWithExpiryData = async (params: {

src/swap/defi/lifi.ts

@@ -43,7 +43,7 @@ import {
   MakeTxParams,
   StringMap
 } from '../types'
-import { getEvmApprovalData, WEI_MULTIPLIER } from './defiUtils'
+import { createEvmApprovalEdgeTransactions, WEI_MULTIPLIER } from './defiUtils'
 
 const pluginId = 'lifi'
 const swapInfo: EdgeSwapInfo = {
@@ -374,7 +374,7 @@ export function makeLifiPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
     const metadataNotes = `DEX Providers: ${providersStr}`
     const { approvalAddress, toAmount, toAmountMin, fromAmount } = estimate
 
-    let preTx: EdgeTransaction | undefined
+    const preTxs: EdgeTransaction[] = []
     let spendInfo: EdgeSpendInfo
     switch (fromWallet.currencyInfo.pluginId) {
       case 'solana': {
@@ -475,44 +475,17 @@ export function makeLifiPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
         const gasPriceGwei = div18(gasPriceDecimal, WEI_MULTIPLIER)
 
         if (sendingToken) {
-          const approvalData = await getEvmApprovalData({
-            contractAddress: approvalAddress,
-            assetAddress: fromContractAddress,
-            nativeAmount
-          })
-
-          const preTxSpendInfo: EdgeSpendInfo = {
-            // Token approvals only spend the parent currency
-            tokenId: null,
-            spendTargets: [
-              {
-                nativeAmount: '0',
-                publicAddress: fromContractAddress
-              }
-            ],
-            memos:
-              approvalData != null
-                ? [{ type: 'hex', value: approvalData }]
-                : undefined,
+          const approvalTxs = await createEvmApprovalEdgeTransactions({
+            request,
+            approvalAmount: fromAmount,
+            tokenContractAddress: fromContractAddress,
+            recipientAddress: approvalAddress,
             networkFeeOption: 'custom',
             customNetworkFee: {
               gasPrice: gasPriceGwei
-            },
-            assetAction: {
-              assetActionType: 'tokenApproval'
-            },
-            savedAction: {
-              actionType: 'tokenApproval',
-              tokenApproved: {
-                pluginId: fromWallet.currencyInfo.pluginId,
-                tokenId: fromTokenId,
-                nativeAmount
-              },
-              tokenContractAddress: fromContractAddress,
-              contractAddress: approvalAddress
             }
-          }
-          preTx = await request.fromWallet.makeSpend(preTxSpendInfo)
+          })
+          preTxs.push(...approvalTxs)
         }
 
         spendInfo = {
@@ -560,7 +533,7 @@ export function makeLifiPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
       fromNativeAmount: nativeAmount,
       metadataNotes,
       minReceiveAmount: toAmountMin,
-      preTx,
+      preTxs,
       request,
       spendInfo,
       swapInfo

src/swap/defi/rango.ts

@@ -46,7 +46,7 @@ import {
   MakeTxParams,
   StringMap
 } from '../types'
-import { WEI_MULTIPLIER } from './defiUtils'
+import { createEvmApprovalEdgeTransactions, WEI_MULTIPLIER } from './defiUtils'
 
 const swapInfo: EdgeSwapInfo = {
   pluginId: 'rango',
@@ -570,7 +570,7 @@ export function makeRangoPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
 
     const providers = route.path.map(p => p.swapper.title)
 
-    let preTx: EdgeTransaction | undefined
+    const preTxs: EdgeTransaction[] = []
     let spendInfo: EdgeSpendInfo
 
     switch (tx.type) {
@@ -685,7 +685,7 @@ export function makeRangoPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
           fromNativeAmount: nativeAmount,
           metadataNotes,
           minReceiveAmount: route.outputAmountMin,
-          preTx,
+          preTxs,
           request,
           makeTxParams,
           swapInfo
@@ -699,32 +699,13 @@ export function makeRangoPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
         }
         const { approveData, approveTo } = evmTransaction
         if (approveData != null && approveTo != null) {
-          const approvalData = approveData.replace('0x', '')
-
-          spendInfo = {
-            tokenId: null,
-            memos: [{ type: 'hex', value: approvalData }],
-            spendTargets: [
-              {
-                nativeAmount: '0',
-                publicAddress: fromContractAddress
-              }
-            ],
-            assetAction: {
-              assetActionType: 'tokenApproval'
-            },
-            savedAction: {
-              actionType: 'tokenApproval',
-              tokenApproved: {
-                pluginId: fromWallet.currencyInfo.pluginId,
-                tokenId: fromTokenId,
-                nativeAmount
-              },
-              tokenContractAddress: fromContractAddress,
-              contractAddress: approveTo
-            }
-          }
-          preTx = await request.fromWallet.makeSpend(spendInfo)
+          const approvalTxs = await createEvmApprovalEdgeTransactions({
+            request,
+            approvalAmount: nativeAmount,
+            tokenContractAddress: fromContractAddress,
+            recipientAddress: approveTo
+          })
+          preTxs.push(...approvalTxs)
         }
         const customNetworkFee = {
           gasLimit:
@@ -791,7 +772,7 @@ export function makeRangoPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
       fromNativeAmount: nativeAmount,
       metadataNotes,
       minReceiveAmount: route.outputAmountMin,
-      preTx,
+      preTxs,
       request,
       spendInfo,
       swapInfo

src/swap/defi/thorchain/swapkit.ts

@@ -35,7 +35,7 @@ import {
   promiseWithTimeout
 } from '../../../util/utils'
 import { EdgeSwapRequestPlugin } from '../../types'
-import { getEvmApprovalData } from '../defiUtils'
+import { createEvmApprovalEdgeTransactions } from '../defiUtils'
 import { MAINNET_CODE_TRANSCRIPTION } from './thorchain'
 import {
   AFFILIATE_FEE_BASIS_DEFAULT,
@@ -331,8 +331,7 @@ export function makeSwapKitPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
     let memo = ''
 
     const publicAddress = targetAddress
-    let approvalData
-    let preTx: EdgeTransaction | undefined
+    const preTxs: EdgeTransaction[] = []
 
     const evmTransaction = asMaybe(asEvmCleaner)(thorSwap.tx)
     const cosmosTransaction = asMaybe(asCosmosCleaner)(thorSwap.tx)
@@ -347,40 +346,14 @@ export function makeSwapKitPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
 
         const dexContractAddress = asString(thorSwap.meta.approvalAddress)
 
-        // Check if token approval is required and return necessary data field
-        approvalData = await getEvmApprovalData({
-          contractAddress: dexContractAddress,
-          assetAddress: sourceTokenContractAddress,
-          nativeAmount
+        const approvalTxs = await createEvmApprovalEdgeTransactions({
+          request,
+          approvalAmount: nativeAmount,
+          tokenContractAddress: sourceTokenContractAddress,
+          recipientAddress: dexContractAddress,
+          networkFeeOption: 'high'
         })
-        if (approvalData != null) {
-          const spendInfo: EdgeSpendInfo = {
-            // Token approvals only spend the parent currency
-            tokenId: null,
-            memos: [{ type: 'hex', value: approvalData }],
-            spendTargets: [
-              {
-                nativeAmount: '0',
-                publicAddress: sourceTokenContractAddress
-              }
-            ],
-            networkFeeOption: 'high',
-            assetAction: {
-              assetActionType: 'tokenApproval'
-            },
-            savedAction: {
-              actionType: 'tokenApproval',
-              tokenApproved: {
-                pluginId: fromWallet.currencyInfo.pluginId,
-                tokenId: fromTokenId,
-                nativeAmount
-              },
-              tokenContractAddress: sourceTokenContractAddress,
-              contractAddress: dexContractAddress
-            }
-          }
-          preTx = await request.fromWallet.makeSpend(spendInfo)
-        }
+        preTxs.push(...approvalTxs)
       }
       memo = evmTransaction.data.replace(/^0x/, '')
     } else if (cosmosTransaction != null) {
@@ -465,7 +438,7 @@ export function makeSwapKitPlugin(opts: EdgeCorePluginOptions): EdgeSwapPlugin {
       swapInfo,
       fromNativeAmount: nativeAmount,
       expirationDate: new Date(expirationMs),
-      preTx,
+      preTxs,
       metadataNotes: notes
     }
   }