執行恢復：PancakeRouter：INVALID_PATH - 交換令牌時

所以我有一個合約，在呼叫時將特定令牌交換到 BNB，它只使用簡單的 uniswap 路由器介面。

它在使用以下程式碼將代幣交換到 BNB 時起作用，(tokenToSwap) 是我正在交換的代幣的地址

address[] memory path = new address[](2);
path[0] = address(tokenToSwap);
path[1] = uniswap.WETH();

但是當我更改程式碼時，將以下程式碼換成 BUSD：

address[] memory path = new address[](3);
path[0] = address(tokenToSwap);
path[1] = uniswap.WETH();
path[2] = address(tokenOut);

此程式碼失敗，我收到以下錯誤消息：execution reverted: PancakeRouter: INVALID_PATH

我使用的路徑是 BUSD 測試網路徑address tokenOut = 0x78867BbEeF44f2326bF8DDd1941a4439382EF2A7;

我錯過了什麼，為什麼我會收到錯誤消息

– 編輯包含所有程式碼（介面已被省略）

contract ACT_SWAP is Context, Ownable {

IUniswapV2Router02 uniswap;

address tokenToSwap;
address SwaptokenOut;

function SetTokenIn(address TokenIn) public onlyOwner() {
   tokenToSwap = TokenIn;
}

function SetTokenOut(address TokenOut) public onlyOwner() {
   SwaptokenOut = TokenOut;
}

constructor() {
   uniswap = IUniswapV2Router02(address(0x9Ac64Cc6e4415144C455BD8E4837Fea55603e5c3));
}

receive() external payable {}

function swapTokensForETH(uint amountIn) external {
   // need to have called approve on this contract first
   IERC20(tokenToSwap).transferFrom(msg.sender, address(this), amountIn);
   address[] memory path = new address[](3);
   path[0] = address(tokenToSwap);
   path[1] = uniswap.WETH(); // returns address of Wrapped Ether
   path[2] = address(SwaptokenOut); // returns address of Wrapped Ether
   IERC20(tokenToSwap).approve(address(uniswap), amountIn);
   uniswap.swapExactTokensForETHSupportingFeeOnTransferTokens(
       amountIn, 
       0, 
       path, 
       address(this), 
       block.timestamp
   );
}

}

你的錯誤是在這一行：

uniswap.swapExactTokensForETHSupportingFeeOnTransferTokens(
       amountIn, 
       0, 
       path, 
       address(this), 
       block.timestamp
   );

當您將代幣兌換成ETH/WETH/BNB/WBNBswapExactTokensForETHSupportingFeeOnTransferTokens(...)時，必須使用該功能。事實上，這個函式的邏輯檢查你是否從該區塊鏈的本機硬幣（或其掛鉤）交換傳遞。您可以在此連結後的第 391 行看到這些條件。要解決此問題，您必須使用呼叫的函式，該函式允許您將通過 thorw 的代幣與原生硬幣或其掛鉤交換。有關更多資訊，請查看我修改的這段程式碼：swapExactTokensForTokensSupportingFeeOnTransferTokens()

function swapTokensForETH(uint amountIn) external {
       // need to have called approve on this contract first
       IERC20(tokenToSwap).transferFrom(msg.sender, address(this), amountIn);
       address[] memory path = new address[](3);
       path[0] = tokenToSwap;
       path[1] = uniswap.WETH(); // returns address of Wrapped BNB
       path[2] = SwaptokenOut;
       IERC20(tokenToSwap).approve(address(uniswap), amountIn);
       uniswap.swapExactTokensForTokensSupportingFeeOnTransferTokens(
           amountIn, 
           0, 
           path, 
           address(this), 
           block.timestamp
       );
   }

引用自：https://ethereum.stackexchange.com/questions/123148