为什么通过“delegateCall”调用的智能合约函数发出的事件会消失？

Question

我有两个交互的智能合约，正在 Hardhat 中开发/测试并部署到RSK：

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1. DelegateCallee带有函数的智能合约getData()，发出一个Received事件：
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contract DelegateCallee {\n  event Received(address sender, uint value);\n  function getData() external payable {\n    emit Received(msg.sender, msg.value);\n  }\n}\n

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2. DelegateCaller智能合约使用 Solidity来delegateCall调用：getData()DelegateCallee
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contract DelegateCaller {\n  address callee;\n\n  constructor(address _callee) {\n    callee = _callee;\n  }\n\n  function delegateCallGetData() external payable {\n    (bool success, ) = callee.delegatecall(\n      abi.encodeWithSelector(DelegateCallee.getData.selector)\n    );\n    require(success, "delegate call failed");\n  }\n}\n

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我正在运行 Hardhat 测试来拦截DelegateCallee. 当我getData()直接调用 时DelegateCallee，事件将按预期发出：

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contract DelegateCallee {\n  event Received(address sender, uint value);\n  function getData() external payable {\n    emit Received(msg.sender, msg.value);\n  }\n}\n

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contract DelegateCaller {\n  address callee;\n\n  constructor(address _callee) {\n    callee = _callee;\n  }\n\n  function delegateCallGetData() external payable {\n    (bool success, ) = callee.delegatecall(\n      abi.encodeWithSelector(DelegateCallee.getData.selector)\n    );\n    require(success, "delegate call failed");\n  }\n}\n

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但是，当我使用DelegateCaller合约时，\n调用它的\n delegateCallGetData()，\n进而调用DelegateCallee合约的\ngetData()函数，该Received事件不会被发出。

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  it(\'getData function on callee should emit the Received event\', async () => {\n    const value = ethers.utils.parseEther(\'1\');\n    const tx = await delagateCallee.getData({ value });\n    await expect(tx)\n      .to.emit(delagateCallee, \'Received\')\n      .withArgs(deployer.address, value);\n  });\n

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  1) Low level calls\n       delegateCallGetData function on caller should emit the Received event on the callee:\n     AssertionError: Expected event "Received" to be emitted, but it wasn\'t\n

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我的事件在哪里丢失了？

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Answer 1

最有可能的是，该Received事件就在那里，尽管 Hardhat 并不认为它是一个DelegateCallee事件。发生这种情况是因为您通过调用该函数delegateCall。Waffle/ Hardhat 期望事件发射器是DelegateCallee智能合约，但由于该函数是在另一个智能合约的上下文中调用的，因此DelegateCaller可能已注册为发射器。为了确保这一点，您应该尝试以下操作：

1. 获取交易收据：

const tx = await delegateCaller.delegateCallGetData({ value });
const receipt = await tx.wait();

2. 查找调用者（而不是被调用者）发出的事件

const event = receipt.events.find(
    (e) => e.address === delegateCaller.address,
);

3. 使用interface.decodeEventLog()（来自 ethers.js）解码此事件的参数

const decodedEvent = delagateCallee.interface.decodeEventLog(
    'Received',
    event.data,
    event.topics,
);

4. 使用断言来验证接收到的值整个测试应该如下所示：

it('should emit on the callee', async () => {
    const value = ethers.utils.parseEther('1');
    const tx = await delegateCaller.delegateCallGetData({ value });
    const receipt = await tx.wait();
    const event = receipt.events.find(
      (e) => e.address === delegateCaller.address,
    );
    const decodedEvent = delagateCallee.interface.decodeEventLog(
      'Received',
      event.data,
      event.topics,
    );
    expect(decodedEvent.sender).to.equal(deployer.address);
    expect(decodedEvent.value).to.equal(value);
});