getting an Invalid input source specified error with the following import when building a smart contract using the remix IDE
import "https://github.com/aave/flashloan-box/blob/Remix/contracts/aave/FlashLoanReceiverBase.sol";
Put together a super basic example smart contract in remix. It compiles just fine if I dont include the import statement.
pragma solidity ^0.6.6;
import "https://github.com/aave/flashloan-box/blob/Remix/contracts/aave/FlashLoanReceiverBase.sol";
contract Inbox {
string public message;
constructor(string memory initialMessage) public {
message = initialMessage;
}
function setMessage(string memory newMessage) public {
message = newMessage;
}
function getMessage() public view returns (string memory) {
return message;
}
}
This issue is happening because of the nested import using relative path.
The FlashLoanReceiverBase.sol is trying to import relative path ./IFlashLoanReceiver.sol (not absolute path https://github.com/aave/flashloan-box/blob/Remix/contracts/aave/IFlashLoanReceiver.sol).
Since you don't have a contract named IFlashLoanReceiver.sol in the same folder as your own contract, this import fails.
Best solution would be to submit a PR to the aave/flashloan-box repository making all import paths absolute.
Related
How to check values of a variables and functions in solidity like javascript via console.log? Because i need visibility of results for deep understanding.
I am newbie...
i tried hardhat but need more understand.
I'm a newbie too, but I know this (I think)!
There is no console in solidity, you need to write a function for this, or just put it public in the variable itself!
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract Value {
uint public num; //add "public" to see the value
function add(uint _num) external{
num += _num;
}
//this function is for returning value
function viewNum() public view returns(uint){
return(num);
}
}
Also use the Remix editor, it's in the browser. There are plenty of videos on the internet!
If you are using hardhat, then you can use console.sol.
You need to import it into your contract.
import "hardhat/console.sol";
Now, you are able to log your variable while you are working.
console.log(__your_variable__);
If you are still looking to log your variables once you deploy your contract, then you need to use event functionality.
Import hardhat console:
import "hardhat/console.sol";
Use console log in your contract
console.log(variable); //Variable value
console.log(1234); //direct value
just like the title says I cannot get using Strings to compile, I keep getting the identifier not found.
This is the start of my .sol contract
import "#openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721EnumerableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "#openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol";
contract NFT is Initializable, StringsUpgradeable, ERC721EnumerableUpgradeable, OwnableUpgradeable {
using Strings for uint256;
Please help!
Thank you!
The imported StringsUpgradeable.sol file contains a library named StringsUpgradeable - not Strings.
Also, since it's a library, it cannot be inherited from, so you need to remove it from the list of the NFT parents.
pragma solidity ^0.8;
import "#openzeppelin/contracts-upgradeable/token/ERC721/extensions/ERC721EnumerableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "#openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "#openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol";
// removed `StringsUpgradable` from the parents list
contract NFT is Initializable, ERC721EnumerableUpgradeable, OwnableUpgradeable {
// replaced `Strings` to `StringsUpgradable`
using StringsUpgradeable for uint256;
}
This has been a problem I've been dealing with for a while now. My temporary solution has been to create a SafeMath.sol file in my Contracts directory and directly import it from there. However, I've been looking for a 'clearer solution' to this... Old way seemed to be directly importing it from a GitHub link, as seen in some repos and other stack overflow posts like such
However, the proper way do this seems to be installing the corresponding oz package (#openzeppelin/contracts-ethereum-package) and importing the file directly into the needed contract i.e.
import "#openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
However, using VSCode, I still get the error Source "#openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol" not found: File import callback not supported
That said, how can I properly import SafeMath?
EDIT: I am using pragma solidity ^0.6.0;
I looked through the node_modules for the package #openzeppelin/contracts. Here is the current correct import path as of posting:
import "#openzeppelin/contracts/utils/math/SafeMath.sol";
This is no longer needed with Solidity version 8
path is different in v 3.0 documentation
I used this:
import "#openzeppelin/contracts/math/SafeMath.sol";
Instead of this:
import "#openzeppelin/contracts/utils/math/SafeMath.sol";
Can be used in the following way:
pragma solidity ^0.5.0;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.3.0/contracts/math/SafeMath.sol";
contract contractForSafeMath {
using SafeMath for uint;
uint256 addResult;
uint256 subResult;
uint256 mulResult;
uint256 divResult;
uint256 modResult;
uint public MAX_VALUE = 2**256 -1;
//overflow
uint256 overflowResult;
function getResults(uint256 a, uint256 b) public{
addResult = SafeMath.add(a,b);
subResult = SafeMath.sub(a,b);
mulResult = SafeMath.mul(a,b);
divResult = SafeMath.div(a,b);
modResult = SafeMath.mod(a,b);
overflowResult = SafeMath.add(SafeMath.add ( (a**b), SafeMath.mul (SafeMath.mul (b, a), b)), (b** b));
}
function addResultVal(uint a, uint b) public view returns(uint256){
return addResult;
}
function subResultVal() public view returns(uint256){
return subResult;
}
function mulResultVal() public view returns(uint256){
return mulResult;
}
function divResultVal() public view returns(uint256){
return divResult;
}
function modResultVal() public view returns(uint256){
return modResult;
}
function overflowResultVal() public view returns(uint256){
return overflowResult;
}
}
Go to the github page for any import you'll like to have for openzeppelin-contracts, "SafeMath" in this case, and copy the page url.
Ex:
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/math/SafeMath.sol";
Import the library right after pragma solidity. Then include it right after the opening of your contract.
pragma solidity ^x.x.x;
import "openzeppelin-solidity/contracts/utils/math/SafeMath.sol";
contract TheNameOfYourContract {
using SafeMath for uint;
.
.
...
}
creating a project from npx hardhat (2.8.3) selecting advanced project and then having a folder structure like this:
project
|--contracts
|--mycontract.sol
|--node_modules
|--{other files & folders}
The error is gone if I import libraries like this inside mycontract.sol:
pragma solidity ^0.8.4;
import "../node_modules/#openzeppelin/contracts/token/ERC20/ERC20.sol";
import "../node_modules/#openzeppelin/contracts/utils/math/SafeMath.sol";
import "../node_modules/#openzeppelin/contracts/access/Ownable.sol";
... other code
But this will not compile at least with hardhat. So it appears Solhint (.solhint.json) requires to know exactly the import paths but it ignores by default (.solhintignore) the node_modules folder. By removing node_modules from .solhintignore and restarting VS Code it works for me.
No longer needed but import that works for pragma solidity ^0.6.0;
would be:
import "#chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol";
I want to use Oraclize in Remix, to test it. I'm too stupid to use their examples.
How can I make this work?
From their Github I took the YouTube-Views code and copied it into Remix
pragma solidity >= 0.5.0 < 0.6.0;
import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";
contract YoutubeViews is usingOraclize {
string public viewsCount;
event LogYoutubeViewCount(string views);
event LogNewOraclizeQuery(string description);
constructor()
public
{
update(); // Update views on contract creation...
}
function __callback(
bytes32 _myid,
string memory _result
)
public
{
require(msg.sender == oraclize_cbAddress());
viewsCount = _result;
emit LogYoutubeViewCount(viewsCount);
// Do something with viewsCount, like tipping the author if viewsCount > X?
}
function update()
public
payable
{
emit LogNewOraclizeQuery("Oraclize query was sent, standing by for the answer...");
oraclize_query("URL", 'html(https://www.youtube.com/watch?v=9bZkp7q19f0).xpath(//*[contains(#class, "watch-view-count")]/text())');
}
}
When I use the viewCount it returns:
0: string:
This happens with all the other examples aswell.
With WolframAlpha eg. I also get the following error:
transact to WolframAlpha.update errored: VM error: revert.
revert The transaction has been reverted to the initial state.
Note: The constructor should be payable if you send value. Debug the transaction to get more information.
Ok you don't see the answer like a normal result in Remix:
You have to go under settings and open the Oraclize plug in.
If you then deploy the contract and or click update, you get the result shown in the plug in.
I'm developing dummy test contract in solidity with truffle, for below code,
pragma solidity ^0.4.17;
import "truffle/Assert.sol";
import "truffle/DeployedAddresses.sol";
import "../contracts/SkillDevelopment.sol";
contract TestSkillDevelopment {
SkillDevelopment skillDevelopmentContract = SkillDevelopment(DeployedAddresses.SkillDevelopment());
function testSetStudentEnrollInfo() public {
skillDevelopmentContract.setStudentEnrollInfo("{\"Info\":[{\"id\":\"06bb05b8b3152b0323f4a9c07ae84f0c513b24946a8f8ec685af7cd763f7ffad\",\"studentId\":6532916,\"parenterId\":6187778,\"schemeId\":3853115,\"batchId\":3458926,\"instructorId\":1175723,\"trainingId\":2599715,\"studentSkillState\":1,\"state\":1}]}");
string expected = string("{\"Info\":[{\"id\":\"06bb05b8b3152b0323f4a9c07ae84f0c513b24946a8f8ec685af7cd763f7ffad\",\"studentId\":6532916,\"parenterId\":6187778,\"schemeId\":3853115,\"batchId\":3458926,\"instructorId\":1175723,\"trainingId\":2599715,\"studentSkillState\":1,\"state\":1}]}");
Assert.equal(skillDevelopmentContract.getStudentEnrollInfo(), expected, "The message should be set");
}
}
but getting error
" TypeError: Explicit type conversion not allowed from "literal_string to "string storage pointer"."
while running "truffle test" command.
Please suggest, how is incorrect here.
Try this instead:
string memory expected = "{\"Info\":[{\"id\":\"06bb05b8b3152b0323f4a9c07ae84f0c513b24946a8f8ec685af7cd763f7ffad\",\"studentId\":6532916,\"parenterId\":6187778,\"schemeId\":3853115,\"batchId\":3458926,\"instructorId\":1175723,\"trainingId\":2599715,\"studentSkillState\":1,\"state\":1}]}";
The default location for a string is storage, which would mean you would have to point it at some state variable in storage. Switching to memory solves that issue. Finally, the explicit cast to string is unneeded (because the value is already a string) and causes the compilation error you saw.