Public variable getter shows as transaction in Remix

Question

As of Solidity 0.6.0+ compiler, my remix shows getter functions, built by public variables, as transactions and, therefore, do not return the value. I searched the solidity 0.6.0 breaking changes but I didn't find any explanation to this. What am I missing?

Example on solidity pragma <=0.5.16:

Example on solidity pragma >=0.6.0:

Answer 1

The problem is related to the ABI JSON produced by the compiler and how the tools use it to determine if a function is view or pure.

As you can see in the docs:

The fields constant and payable are deprecated and will be removed in the future. Instead, the stateMutability field can be used to determine the same properties.

Now, see how different are the JSON generated using the following simple contract:

contract C1 {

    uint x;

    function setX(uint _x) public {
        x = _x;
    }

    function getX() public view returns (uint) {
        return x;
    }
}

Please, note that only the ABI for the getX() function is shown.

---

JSON format for v0.6.0

{
    "inputs": [],
    "name": "getX",
    "outputs": [
        {
            "internalType": "uint256",
            "name": "",
            "type": "uint256"
        }
    ],
    "stateMutability": "view",
    "type": "function"
},

---

JSON format for v0.5.13

{
    "constant": true,
    "inputs": [],
    "name": "getX",
    "outputs": [
        {
            "internalType": "uint256",
            "name": "",
            "type": "uint256"
        }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
},

EDIT:

As we can see here, Remix used only the constant field to determine if a function is view or pure.

var lookupOnly = args.funABI.constant

Now, this is solve, as we can see here.

const lookupOnly = args.funABI.stateMutability === 'view' || args.funABI.stateMutability === 'pure' || args.funABI.constant