1

I have a flow which yields 4 events.

When I obtain the transaction hash via web3.js, I can see that all 4 events are included in the receipt logs, but only the last 2 events are in the decoded logs (which means I have to decode the first 2 events myself):

{
    "receipt": {
        ...
        "logs": [
            {
                "logIndex": 0,
                ...
            },
            {
                "logIndex": 1,
                ...
            },
            {
                "logIndex": 2,
                ...
            },
            {
                "logIndex": 3,
                ...
            }
        ],
        ...
    },
    "logs": [
        {
            "logIndex": 2,
            ...
        },
        {
            "logIndex": 3,
            ...
        }
    ]
}

What is the reason for this?

  • It might be helpful if you more fully explained the flow you mention. My guess it there is something in the flow (outside of web3) that's causing this, but without context, it's hard to tell. Maybe I'm misunderstanding your question though. – Thomas Jay Rush May 12 '18 at 21:50
  • @ThomasJayRush: I can add my on-chain side (Solidity code), but I think it would just be TMI. From web3, I am invoking a contract function which calls another contract function, etc. At the end of this flow, there are 4 events generated. The receipt part shows it clearly, but the decoded-log part contains only partial information. When I run similar flows with only 2 events, all of them are decoded. Perhaps there's a web3 limitation on the amount of decoded events, but it clearly feels like an issue on web3 side. Thank you!!! – goodvibration May 13 '18 at 5:48
  • Have you tried the gitter channel? – Thomas Jay Rush May 13 '18 at 10:40
  • @ThomasJayRush: You mean, ask it on GitHub? – goodvibration May 13 '18 at 11:08
  • @ThomasJayRush: I think I've got the answer, see below. – goodvibration May 13 '18 at 12:21
2

OK, I understand the reason:

All the events generated during the execution of the function called by web3 are included in the receipt logs, but only the events generated in the scope of the contract in which the function is implemented are included in the decoded logs.

For example, given the following on-chain code:

File IContract1.sol:

pragma solidity ^0.4.18;

interface IContract1 {
    function func(uint256 x) external returns (uint256);
}

File Contract1.sol:

pragma solidity ^0.4.18;
import "./IContract1.sol";

contract Contract1 is IContract1{
    event Event1(uint256 x);
    function func(uint256 x) external returns (uint256) {
        Event1(x);
        return x;
    }
}

File Contract2.sol:

pragma solidity ^0.4.18;
import "./IContract1.sol";

contract Contract2 {
    IContract1 private contract1;
    function Contract2(IContract1 _contract1) public {
        contract1 = _contract1;
    }
    event Event2(uint256 x);
    function func(uint256 x) external returns (uint256) {
        Event2(x);
        return contract1.func(x);
    }
}

If I execute the following off-chain code:

let contract1 = await artifacts.require("Contract1.sol").new();
let contract2 = await artifacts.require("Contract2.sol").new(contract1.address);

let hash = await contract2.func(42);

Then hash.receipt.logs will include both Event1 and Event2.

But hash.logs will include only Event2.

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