contract-debuggingcontract-developmentremixsolidity
I'm using Remix IDE to compile and run my code, when I tried running the function it had an error, it suggested to debug. I have not used the debugger Remix before so I want to ask:
How do you use the debugger on Remix?
Can you add breakpoints in your code?
Here's my error I'm getting:
Finally... I have code that works...
Caller code:
pragma solidity ^0.4.24;
contract Caller {
address public called_address;
function set_address(address _addy) public {
called_address = address(_addy);
}
function getCalleeValue() public view returns (uint){
Called c = Called(called_address);
return c.get();
}
function setCalleeValue(uint newValue) public returns (uint){
Called c = Called(called_address);
c.set(newValue);
}
interface Called{
function set(uint) external;
function get() external view returns (uint);
}
Called Contract code:
pragma solidity ^0.4.24;
contract Called{
uint public myuint;
function myuint() public view returns(uint _myuint) {
_myuint = myuint;
}
function set(uint _var) public {
myuint = _var;
}
function get() public view returns (uint){
return myuint;
}
}
It seems like there was an issue with how the first code stored the addresses. Now that I have changed the code to store the address explicitly as an address type, there is no issue in Remix IDE using Web3 provider and Genache as the local blockchain.
As @Chan-Ho Suh suggested in the comment you are looking through the debug of the transaction of the contract being deployed. As in your initial question, there is no constructor, there is nothing to step through.
The problem is that you are not calling the function LoopCounter after deploying the contract in your step 5, you need to enter a value and click the function name for it to run.
In the Deploy and Run Transactions screen, once you deploy your contract, you will see a gray box representing the contract that you just deployed (1). If you click the arrow in this box, it will show you the functions available in this contract. Add the number you'd like to test and click the blue button with the function name to call the function (2). Now you'll see another log in the console which you can use to debug this function (3). Using this debug, the debugger steps through the function as desired.
(the problem is that you need return returnValue instead of just returnValue)
Best Answer
You can add breakpoints in your code to use when debugging your smart contract. You can do this by clicking on the line number of where you want to set your breakpoint.
In this example, I set my breakpoint at
line 24when the constructor is called.There are several ways to debug your contract. You can click on the Debugger tab and insert a block number or transaction hash and press the play button to go through the steps. But what I like to do is to run a method I want to test and then press the
Debugbutton in the console. That will load up the correct transaction hash.In this example, I put a breakpoint when the constructor is called, initialized my contract in the Run tab, and then pressed the
Debugbutton in the console.You can see that the debugger stopped inside my constructor. You can use the buttons under the slider to step in, step back, step over, step out, etc. The buttons under that allow you to navigate through your breakpoints.
The transaction slider allows you to quickly maneuver around code as it goes through that specific transaction.
One thing that I like to do when a transaction fails for whatever reason is move the slider to the very end. This will most likely be where your code stopped and could be the cause of the failure.
You'll also notice as you go through the transaction that you'll be able to see the values of state variables and local variables, which will be helpful when you're debugging your code.