feat: USDT approve(0) reset flow for Ethereum mainnet swap

apps/extension/src/languages/en.json

@@ -465,6 +465,8 @@
   "page.ibc-swap.components.slippage-modal.label.slippage-custom": "Custom Slippage",
   "page.ibc-swap.components.swap-not-available-modal.title": "Swap Not Available",
   "page.ibc-swap.components.swap-not-available-modal.paragraph": "Swap is currently not available for this token.",
+  "page.ibc-swap.usdt-allowance-reset.description": "This swap requires 2 approvals.{br}Let's start by resetting your USDT spending limit to 0.",
+  "page.ibc-swap.usdt-allowance-reset.button": "Reset Allowance",
   "page.ibc-swap.button.terms-of-use.title": "Terms of Use",
   "page.ibc-swap.loading.first": "Finding the best route…",
   "page.ibc-swap.loading.second": "Checking a few more routes…",

apps/extension/src/languages/ko.json

@@ -460,6 +460,8 @@
   "page.ibc-swap.components.slippage-modal.label.slippage-custom": "커스텀 설정",
   "page.ibc-swap.components.swap-not-available-modal.title": "교환 불가능",
   "page.ibc-swap.components.swap-not-available-modal.paragraph": "현재 이 토큰에 대한 교환이 불가능합니다.",
+  "page.ibc-swap.usdt-allowance-reset.description": "이 스왑은 2번의 승인이 필요합니다.{br}먼저 USDT 지출 한도를 0으로 초기화합니다.",
+  "page.ibc-swap.usdt-allowance-reset.button": "지출 한도 초기화",
   "page.ibc-swap.button.terms-of-use.title": "이용약관",
   "page.ibc-swap.loading.first": "가장 좋은 경로를 찾고 있어요…",
   "page.ibc-swap.loading.second": "조금만 더 확인할게요…",

apps/extension/src/languages/zh-cn.json

@@ -426,6 +426,8 @@
   "page.ibc-swap.components.slippage-modal.label.slippage-custom": "自定义滑价",
   "page.ibc-swap.components.swap-not-available-modal.title": "兑换不可用",
   "page.ibc-swap.components.swap-not-available-modal.paragraph": "当前无法兑换此代币。",
+  "page.ibc-swap.usdt-allowance-reset.description": "此兑换需要2次批准。{br}首先将您的USDT支出限额重置为0。",
+  "page.ibc-swap.usdt-allowance-reset.button": "重置支出限额",
   "page.ibc-swap.loading.first": "正在寻找最佳路线…",
   "page.ibc-swap.loading.second": "再帮您确认一下…",
 

apps/extension/src/pages/ibc-swap/hooks/use-query-route-refresh.ts

@@ -5,8 +5,11 @@ import { useEffect, useRef } from "react";
 export function useQueryRouteRefresh(
   queryRoute: ObservableQueryRouteInnerV2 | undefined,
   isSwapExecuting: boolean,
-  isButtonHolding: boolean
+  isButtonHolding: boolean,
+  isApprovalResetRequired?: boolean
 ) {
+  const isPaused =
+    isSwapExecuting || isButtonHolding || !!isApprovalResetRequired;
   const prevIsSwapLoadingRef = useRef(isSwapExecuting);
   const prevIsButtonHoldingRef = useRef(isButtonHolding);
 
@@ -16,8 +19,7 @@ export function useQueryRouteRefresh(
     if (
       queryRoute &&
       !queryRoute.isFetching &&
-      !isSwapExecuting &&
-      !isButtonHolding &&
+      !isPaused &&
       queryRoute.response?.timestamp
     ) {
       const diff = Date.now() - queryRoute.response.timestamp;
@@ -45,12 +47,7 @@ export function useQueryRouteRefresh(
         (prevIsButtonHolding && !currentIsButtonHolding))
     ) {
       const timeoutId = setTimeout(() => {
-        if (
-          queryRoute &&
-          !queryRoute.isFetching &&
-          !isSwapExecuting &&
-          !isButtonHolding
-        ) {
+        if (queryRoute && !queryRoute.isFetching && !isPaused) {
           queryRoute.fetch();
         }
       }, 3000);
@@ -61,18 +58,19 @@ export function useQueryRouteRefresh(
 
     prevIsSwapLoadingRef.current = currentIsSwapLoading;
     prevIsButtonHoldingRef.current = currentIsButtonHolding;
-  }, [queryRoute, queryRoute?.isFetching, isSwapExecuting, isButtonHolding]);
+  }, [
+    queryRoute,
+    queryRoute?.isFetching,
+    isSwapExecuting,
+    isButtonHolding,
+    isPaused,
+  ]);
 
   // QueryRouteRefreshInterval 마다 route query 자동 refresh
   useEffect(() => {
-    if (
-      queryRoute &&
-      !queryRoute.isFetching &&
-      !isSwapExecuting &&
-      !isButtonHolding
-    ) {
+    if (queryRoute && !queryRoute.isFetching && !isPaused) {
       const timeoutId = setTimeout(() => {
-        if (!queryRoute.isFetching && !isSwapExecuting && !isButtonHolding) {
+        if (!queryRoute.isFetching && !isPaused) {
           queryRoute.fetch();
         }
       }, SwapAmountConfig.QueryRouteRefreshInterval);
@@ -85,5 +83,5 @@ export function useQueryRouteRefresh(
     // queryRoute.isFetching는 현재 fetch중인지 아닌지를 알려주는 값이므로 deps에 꼭 넣어야한다.
     // queryRoute는 input이 같으면 reference가 같으므로 eslint에서 추천하는대로 queryRoute만 deps에 넣으면
     // queryRoute.isFetching이 무시되기 때문에 수동으로 넣어줌
-  }, [queryRoute, queryRoute?.isFetching, isSwapExecuting, isButtonHolding]);
+  }, [queryRoute, queryRoute?.isFetching, isPaused]);
 }

apps/extension/src/pages/ibc-swap/hooks/use-usdt-approval-reset.ts

@@ -0,0 +1,227 @@
+import React from "react";
+import { AppCurrency } from "@keplr-wallet/types";
+import {
+  EthereumAccountStore,
+  EthereumQueries,
+  UnsignedEVMTransactionWithErc20Approvals,
+  isApproveResetRequired,
+} from "@keplr-wallet/stores-eth";
+import { SwapAmountConfig } from "@keplr-wallet/hooks-internal";
+import { IFeeConfig, IGasSimulator, ISenderConfig } from "@keplr-wallet/hooks";
+import { Dec } from "@keplr-wallet/unit";
+import { isEVMFeeConfig } from "../../../hooks/fee";
+import { IBCSwapConfig } from "../../../stores/ui-config/ibc-swap";
+
+export function useUsdtApprovalReset({
+  amountConfig,
+  senderConfig,
+  inChainId,
+  inCurrency,
+  queriesStore,
+  ethereumAccountStore,
+  feeConfig,
+  gasSimulator,
+  ibcSwapConfig,
+  onSignComplete,
+  onResetSuccess,
+  onResetFailed,
+}: {
+  amountConfig: SwapAmountConfig;
+  senderConfig: ISenderConfig;
+  inChainId: string;
+  inCurrency: AppCurrency;
+  queriesStore: {
+    get(chainId: string): EthereumQueries;
+  };
+  ethereumAccountStore: EthereumAccountStore;
+  feeConfig: IFeeConfig;
+  gasSimulator: IGasSimulator;
+  ibcSwapConfig: IBCSwapConfig;
+  onSignComplete: () => void;
+  onResetSuccess: () => void;
+  onResetFailed: () => void;
+}) {
+  const isApprovalResetPending = ibcSwapConfig.isApprovalResetPending;
+  const setIsApprovalResetPending = (pending: boolean) =>
+    ibcSwapConfig.setIsApprovalResetPending(pending);
+
+  // Detect USDT from swap inputs (not getTxsIfReady) to avoid flicker
+  const usdtContractAddress = inCurrency.coinMinimalDenom.startsWith("erc20:")
+    ? inCurrency.coinMinimalDenom.replace("erc20:", "")
+    : undefined;
+  const isInputUsdtRequiringReset =
+    usdtContractAddress != null &&
+    isApproveResetRequired(inChainId, usdtContractAddress);
+
+  // Cache the spender from tx data — survives getTxsIfReady() returning null during route transitions
+  const approvalSpenderRef = React.useRef<string | null>(null);
+  const txs = amountConfig.getTxsIfReady();
+  if (txs && txs.length > 0) {
+    const tx = txs[0];
+    if ("requiredErc20Approvals" in tx) {
+      const approval = (tx as UnsignedEVMTransactionWithErc20Approvals)
+        .requiredErc20Approvals?.[0];
+      // Clear stale spender when the new quote no longer needs an approval
+      // (e.g., user lowered amount below existing allowance).
+      approvalSpenderRef.current = approval?.spender ?? null;
+    }
+  }
+
+  const sender = senderConfig.sender;
+  const allowanceQuery =
+    isInputUsdtRequiringReset &&
+    sender &&
+    usdtContractAddress &&
+    approvalSpenderRef.current
+      ? queriesStore
+          .get(inChainId)
+          .ethereum.queryERC20Allowance.getAllowance(
+            usdtContractAddress,
+            sender,
+            approvalSpenderRef.current
+          )
+      : null;
+
+  const hasValidAmount = (() => {
+    try {
+      const amount = amountConfig.amount[0]?.toCoin().amount;
+      return amount != null && amount !== "0";
+    } catch {
+      return false;
+    }
+  })();
+
+  const requiresApprovalReset =
+    hasValidAmount &&
+    isInputUsdtRequiringReset &&
+    (isApprovalResetPending ||
+      (allowanceQuery != null && allowanceQuery.allowance > BigInt(0)));
+
+  // P2 fallback: if pending flag is stuck after tx fulfill callback missed,
+  // clear it once on-chain allowance confirms the reset succeeded.
+  React.useEffect(() => {
+    if (
+      isApprovalResetPending &&
+      allowanceQuery != null &&
+      !allowanceQuery.isFetching &&
+      allowanceQuery.allowance === BigInt(0)
+    ) {
+      setIsApprovalResetPending(false);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [
+    isApprovalResetPending,
+    allowanceQuery?.allowance,
+    allowanceQuery?.isFetching,
+  ]);
+
+  const handleResetAllowance = async () => {
+    const txs = amountConfig.getTxsIfReady();
+    if (!txs || txs.length === 0) return;
+
+    const tx = txs[0];
+    if (!("requiredErc20Approvals" in tx)) return;
+
+    const approval = (tx as UnsignedEVMTransactionWithErc20Approvals)
+      .requiredErc20Approvals?.[0];
+    if (!approval) return;
+
+    const chainId = `eip155:${tx.chainId!}`;
+    const ethereumAccount = ethereumAccountStore.getAccount(chainId);
+
+    const isInCurrencyErc20 =
+      ("type" in inCurrency && inCurrency.type === "erc20") ||
+      inCurrency.coinMinimalDenom.startsWith("erc20:");
+    if (!isInCurrencyErc20) return;
+
+    const resetTx = ethereumAccount.makeErc20ApprovalTx(
+      {
+        ...inCurrency,
+        type: "erc20",
+        contractAddress: inCurrency.coinMinimalDenom.replace("erc20:", ""),
+      },
+      approval.spender,
+      "0"
+    );
+
+    setIsApprovalResetPending(true);
+
+    try {
+      // Simulate gas for the approve(0) tx
+      const gasResult = await ethereumAccount.simulateGas(sender, resetTx);
+      const gasLimit = Math.ceil(
+        gasResult.gasUsed * gasSimulator.gasAdjustment
+      );
+
+      // Build fee object
+      let feeObject: Record<string, unknown>;
+      if (isEVMFeeConfig(feeConfig)) {
+        const eip1559Fees = feeConfig.getEIP1559TxFees(feeConfig.type);
+        if (eip1559Fees.maxFeePerGas && eip1559Fees.maxPriorityFeePerGas) {
+          feeObject = {
+            type: 2,
+            maxFeePerGas: `0x${BigInt(
+              eip1559Fees.maxFeePerGas.truncate().toString()
+            ).toString(16)}`,
+            maxPriorityFeePerGas: `0x${BigInt(
+              eip1559Fees.maxPriorityFeePerGas.truncate().toString()
+            ).toString(16)}`,
+            gasLimit: `0x${gasLimit.toString(16)}`,
+          };
+        } else {
+          feeObject = {
+            gasPrice: `0x${BigInt(
+              (eip1559Fees.gasPrice ?? new Dec(0)).truncate().toString()
+            ).toString(16)}`,
+            gasLimit: `0x${gasLimit.toString(16)}`,
+          };
+        }
+      } else {
+        feeObject = {
+          gasLimit: `0x${gasLimit.toString(16)}`,
+        };
+      }
+
+      await ethereumAccount.sendEthereumTx(
+        sender,
+        { ...resetTx, ...feeObject },
+        {
+          onBroadcastFailed: () => {
+            setIsApprovalResetPending(false);
+            onSignComplete();
+          },
+          onBroadcasted: () => {
+            onSignComplete();
+          },
+          onFulfill: (txReceipt) => {
+            if (txReceipt.status === "0x1") {
+              if (allowanceQuery) {
+                allowanceQuery.fetch();
+              }
+              onResetSuccess();
+            } else {
+              onResetFailed();
+            }
+            setIsApprovalResetPending(false);
+          },
+        }
+      );
+    } catch {
+      setIsApprovalResetPending(false);
+      onResetFailed();
+    }
+  };
+
+  const refetchAllowance = () => {
+    if (allowanceQuery) {
+      allowanceQuery.fetch();
+    }
+  };
+
+  return {
+    requiresApprovalReset,
+    isApprovalResetPending,
+    handleResetAllowance,
+    refetchAllowance,
+  };
+}