File import callback not supported?

Question

Tried to run:

1.) Dappuniversity project (dappuniversity/dbank) 2.) pet-shop-tutorial

Truffle v5.3.3 (core: 5.3.3) Node v14.15.5

How can ser compile code @ the 0.8.4 to import OpenZeppelin’s ERC20.sol template, when Truffle requires it’s compiler/solc to match 5.3.3?

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract Token is ERC20 {

  //add minter variable

  //add minter changed event

  constructor() public payable ERC20("Name", "Symbol") {

    //assign initial minter

  }

  //Add pass minter role function

  function mint(address account, uint256 amount) public {

    //check if msg.sender has a minter role

    _mint(account, amount);

  }

}

Source “@openzeppelin/contracts/token/ERC20/ERC20.sol” not found: File import callback not supported

Haggle

any luck? same boat here – Comical

Try deleting the Build Artifacts (.json files) and run the command again. – Exuviae

Can you specify the IDE you're using? – Woodenhead

Answer 1

The Error:
Source "@openzeppelin/contracts/token/ERC20/ERC20.sol" not found: File import callback not supported

Step 1:

Install the Solidity Extention

Step 2:

• Right click on the error.
• Select "Change the default workspace..."

Step 3:

Select localNodeModule
Might have to restart the IDE

Hogle

Not working for me as well – Anthonyanthophore

For me changing it to localFile did the trick – Cyclothymia

That was it, thanks – Nourish

In some files this solution worked but for one file I had to choose localFile to make it work. – Caius

Answer 2

For me (running Win 10) this error resolved when I cleared out a setting in the VSCode solidity extension.

Extensions menu
--> Right click Solidity by Juan Blanco
--> Extension Settings
--> Scroll to "Solidity:Package Default Dependencies Contracts Directory"
--> Delete the default value

The default value was pointing things to the wrong path.

https://github.com/juanfranblanco/vscode-solidity/issues/178

Starve

Answer 3

If the node_modules directory that contains the script you want to import is not at the root of your VSCode workspace, you can point the solidity extension to it manually in .vscode/settings.json like so:

{
  "solidity.packageDefaultDependenciesDirectory": "path/to/sub/dir/node_modules"
}

Hazelton

Answer 4

The error is caused by the solc-js compiler. The GitHub page is https://github.com/ethereum/solc-js

You need to compile with an import callback, I do not know how Truffle handles this, but in case you were compiling yourself programmatically, you would have to use an import callback as in the following code (example taken from the GitHub page, the findImports function changed to how it is working for me):

const solc = require('solc');

const input = {
  language: 'Solidity',
  sources: {
    'test.sol': {
      content: 'import "lib.sol"; contract C { function f() public { 
L.f(); } }'
    }
  },
  settings: {
    outputSelection: {
      '*': {
        '*': ['*']
      }
    }
  }
};

function findImports(relativePath) {
  //my imported sources are stored under the node_modules folder!
  const absolutePath = path.resolve(__dirname, 'node_modules', relativePath);
  const source = fs.readFileSync(absolutePath, 'utf8');
  return { contents: source };
}

// New syntax (supported from 0.5.12, mandatory from 0.6.0)
var output = JSON.parse(
  solc.compile(JSON.stringify(input), { import: findImports })
);

Peel

Answer 5

If you're using VSCode, this error is caused when your IDE fails to resolve the import paths.

Some contract packages contain contracts in the contracts folder, whereas others may contain subfolders containing contracts folders in them, and this causes path errors.

If you're using Solidity extension by Juan, make sure you have your remappings correct:

This is an example of the settings.json file that would pop up if you choose to modify the remappings. Note that the remapping template is: NAME_OF_PACKAGE/=node_modules/PATH_TO_PACKAGE:

{
   ...,
   "solidity.remappingsUnix": [
        "@uniswap/=node_modules/@uniswap/",
        "@openzeppelin/=node_modules/@openzeppelin/"
   ]
}

Lorrin

Answer 6

Create a folder .vscode in your root folder and then create a file settings.json inside .vscode with the following content. Ensure the path is correct:

{
    "solidity.remappings":["@openzeppelin/=/Users/john/workspace/myproject/smart_contract/node_modules/@openzeppelin"] 
}

Saddlebow

This worked for me, but simply as a side note: I could use the relative path instead of the absolute path as shown. – Eisegesis

You can add these lines to add support for all remappings: { "solidity.packageDefaultDependenciesContractsDirectory": "src", "solidity.packageDefaultDependenciesDirectory": "lib" } – Woodenhead

Answer 7

Install any missing dependencies and add them to your package.json.
Note that some packages, like @chainlink/contracts require using yarn, because they use yarn workspaces.

npm ERR! Error: Please use yarn to install dependencies

for example:

yarn add @chainlink/contracts

However, I did not make it work for packages that include @version tag, because the import path does not match any folder in node_modules.

npm i @openzeppelin/[email protected]

The error went away when I removed the version from the path, but I don't know how legit this is. It does still compile though ¯\(ツ)/¯

Bonni

Answer 8

I solve this issue by setting extension config solidity.monoRepoSupport to false (default is true).

Biweekly

Answer 9

I am running hardhat in a yarn package, under packages/. To eliminate this error, go to the preferences for the Solidity plugin.

Preference: Package Default Dependencies Directory

Value: packages/hardhat/node_modules

Corsica

Answer 10

For me, the following worked

Under solidity plugin settings on vs code(I'm on mac), I made sure that node_modules is removed from Solidity: Package Default Dependencies Directory box.

As soon as I remove this, the error goes away.

If I add node_modules back in that box, the error comes again.

PS: I am assuming that in your repo directory, you have already installed openzeppelin correctly

npm install @openzeppelin/contracts

Coeternal

Answer 11

A simple hack to this would be import from the absolute path of the module. Something like import "/yourApp/node_modules/@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol" in your .sol file! This is hassle free and works 100% :)

Though the above will remove the error from VSCODE but when you will compile the contract it will throw errors. So it would be better to be with the VSCODE error and get the contract compiled and deployed without errors!! :D

Marcelina

Answer 12

ERC20 file requires other files

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

it is not clear if you have correctly installed OpenZeppelin or not.

Hamsun

Answer 13

If you are using VSCODE solidity extension: make sure you are running VSCODE from the directory below /contracts/ and /node_modules/ where the package.json lives.

Paths will be updated and the errors will go away.

Longsufferance

I'm dealing with the same issue... can you go further into detail? I see the packages in the package.json and node modules and i'm getting the same error? – Ventricose

Answer 14

Before trying anything, in case any of you copied the entire contract from a tutorial, first try changing the contract 'Name'. For me, I noticed I still had the original contract name here, and once I changed it to MY project (contract) name, then error went away. Worth a shot before tinkering with the extension settings:

E.g. Instead of:

contract OriginalTutorialContractName is ERC721, Ownable {

make sure to update for your project:

contract YourContractNameHere is ERC721, Ownable {

Lengthy

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Specific

Answer 15

I am on Linux working with a truffle project. I passed the relative path even though node_modules is automatically set as the Package Default Dependencies Contracts Directory setting of the solidity extension:

 import "../node_modules/@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
 import "../node_modules/@openzeppelin/contracts/utils/Counters.sol";

Rea

Answer 16

If u have installed the extension and tried importing from node modules, then try to restart VS, this will refresh the cache and fix it.

Flavine

Answer 17

I had a similar solution to @APerson1000 in this thread, except I needed to remove the node_modules reference in the Solidity extension settings in VSCode, in particular the Solidity: Package Default Dependencies Directory field.

Redeem

Answer 18

After countless hours, I noticed I had a package.json or a hardhat.config.js upward in the hierarchy's repo, due to a "npx hardhat" or "yarn" in the wrong repo. Deleting the configs files, the node_modules upward, following by a reboot solved my case !

If the error still persist, just copy paste your repo directly in your home repo and give it a try here. If the error disappear you have to find the malicious config file somewhere in your path...

An

Answer 19

In my case, I forgot installing openzeppelin contract.

Install openzeppelin contract by running-

npm install @openzeppelin/contracts

Confirm workspace compiler is set to localNodeModule

Note - Reloading vs code window might help too.

Implacental

Answer 20

I resolved it by changing vscode solidity extension version to v0.0.135.

Comte