Can't import openzeppelin node_modules: File import callback not supported

Question

Whenever I try to compile my solidity contract, the error ParserError: Source \"@OpenZeppelin/contracts/math/SafeMath.sol\" not found: File import callback not supported gets thrown.

pragma solidity ^0.7.0;

import "@OpenZeppelin/contracts/token/ERC20/ERC20.sol";
import "@OpenZeppelin/contracts/math/SafeMath.sol";

Any ideas what could be causing this?

Answer 1

Make sure you opened VS Code in the root directory of the project.

In my case, this is how my VS Code directory looked like when I get that same error.

projects
 |___MyContract
   |__contracts
     |__Contract.sol

Reopening VS Code in the MyContract directory fixes it.

MyContract
 |__contracts
   |__Contract.sol

Answer 2

I have the same problem right now. I'm using truffle+node and I fixed it modifying the import path to a relative path, for example,

pragma solidity ^0.7.0;

import "../node_modules/OpenZeppelin/contracts/token/ERC20/ERC20.sol";
import "../node_modules/OpenZeppelin/contracts/math/SafeMath.sol";

I'm not 100% sure why this happen but I hope I helped you.

Answer 3

After installing OpenZeppelin close your IDE and re-open it.

Answer 4

For some environments, SafeMath has a different path

import "@openzeppelin/contracts/utils/math/SafeMath.sol";

Answer 5

Make sure you installed openzeppelin

npm install --save @openzeppelin/[email protected]