Received the result, but failed to decode

[Gelassen]

Hello,

I have been working on the one function call which returns an array with struct items. The issue is it fails, but fails in the Interface.decodeFunctionResult code block -- it receives data and can not decode.

Encoded data is:

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

which represents an array with single struct

struct Match {
    address _userFirst;
    uint256 _valueOfFirstUser; // tokenId of SwapValue.sol owned by _userFirst
    address _userSecond;
    uint256 _valueOfSecondUser; // tokenId of SwapValue.sol owned by _userSecond
    bool _approvedByFirstUser;
    bool _approvedBySecondUser;
}

class SwapChainV2 extends Contract {

    constructor(privateKey, nodeUrl, contractAddress) {
        super();
        let swapChainAbiJson = [
            "function registerUser(address user) public override",
            "function getUsers() public view override returns (address[] memory)",
            "function getMatches(address userFirst, address userSecond) external view override returns (Match[] memory)"
        ];
        this.signerInstance = this.getWalletWithProvider(privateKey, nodeUrl);
        this.swapChainContract = new ethers.Contract(
            contractAddress, 
            swapChainAbiJson, 
            this.signerInstance
        );
        
    }

    async getMatches(userFirstAddress, userSecondAddress) {
        return await this.swapChainContract.getMatches(userFirstAddress, userSecondAddress);
    }

    async getUsers() {
        return await this.swapChainContract.getUsers();
    }
}

Environment: "ethers": "^5.7.2"

This morning I got the similar error when used web3j, here is details and now I have got the similar error with ether.js. Do I use any forbidden format in my struct? Do you support arrays with struct?

Thank you in advance with your help.

[ricmoo]

Yes. Arrays and tuples are fully supported. Can you include the error?

[Gelassen]

Sure, here is full stacktrace:

/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/logger/lib/index.js:238
        var error = new Error(message);
                    ^

Error: call revert exception [ See: https://links.ethers.org/v5-errors-CALL_EXCEPTION ] (method="getMatches(address,address)", data="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", errorArgs=null, errorName=null, errorSignature=null, reason=null, code=CALL_EXCEPTION, version=abi/5.7.0)
    at Logger.makeError (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/logger/lib/index.js:238:21)
    at Logger.throwError (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/logger/lib/index.js:247:20)
    at Interface.decodeFunctionResult (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/abi/lib/interface.js:388:23)
    at Contract.<anonymous> (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/contracts/lib/index.js:395:56)
    at step (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/contracts/lib/index.js:48:23)
    at Object.next (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/contracts/lib/index.js:29:53)
    at fulfilled (/home/gelassen/Workspace/Personal/Android/swap/server/node_modules/@ethersproject/contracts/lib/index.js:20:58)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  reason: null,
  code: 'CALL_EXCEPTION',
  method: 'getMatches(address,address)',
  data: '0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000100000000000000000000000062f8dc8a5c80db6e8fcc042f0cc54a298f8f2ffd000000000000000000000000000000000000000000000000000000000000000000000000000000000000000052e7400ba1b956b11394a5045f8bc3682792e1ac000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001',
  errorArgs: null,
  errorName: null,
  errorSignature: null,
  address: '0x9ceAECB2931a9681Bf23c79F68615ec96BcB0EFd',
  args: [
    '0x62F8DC8a5c80db6e8FCc042f0cC54a298F8F2FFd',
    '0x52E7400Ba1B956B11394a5045F8BC3682792E1AC'
  ],
  transaction: {
    data: '0xe4f02ae600000000000000000000000062f8dc8a5c80db6e8fcc042f0cc54a298f8f2ffd00000000000000000000000052e7400ba1b956b11394a5045f8bc3682792e1ac',
    to: '0x9ceAECB2931a9681Bf23c79F68615ec96BcB0EFd',
    from: '0x3DB851dFd07a1665F95E58cE327d33f2D8E8a030'
  }
}

Node.js v18.0.0

[ricmoo]

Oh. You cannot use Match[] as your return type. There is no way from the ABI to know what a “Match” is. You need to specify the tuple format: function getMatches(address, address) view returns ((address,uint,address,uint,bool,bool)[]).

In v6.1 there will be an ABI type for structure to make this easier.

Let me know if that works.

[Gelassen]

Yes, it works. Thank you!