@openzeppelin/contracts/utils/Counters.sol, imported from [filename].sol, not found エラーへの対処法

はじめに

.solファイルを実行したら、このようなエラーが出ました。

Error HH404: File @openzeppelin/contracts/utils/Counters.sol, imported from contracts/MyEpicGame.sol, not found.

For more info go to https://hardhat.org/HH404 or run Hardhat with --show-stack-traces
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed.
Exit code: 1
Command: /Users/username/.nvm/versions/node/v20.11.0/bin/node
Arguments: /opt/homebrew/Cellar/yarn/1.22.19/libexec/lib/cli.js run:script
Directory: /Users/username/github/ETH-NFT-Game/packages/contract
Output:

info Visit https://yarnpkg.com/en/docs/cli/workspace for documentation about this command.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

結論

原因

OpenZeppelin V5.0では Counters が削除されたため。

他の機能やコントラクトも削除されています。

• Address.isContract
• Counters
• SafeMath
• SignedSafeMath
• GovernorCompatibilityBravo
• GovernorVotesComp
• TokenTimelock (in favor of VestingWallet)
• ERC777
• All cross-chain contracts (including AccessControlCrossChain)
• All presets in favor of OpenZeppelin Contracts Wizard

対処法

この記事を参考に書き換え、エラーが解消されました。

import

v4

import {Counters} from "@openzeppelin/contracts/utils/Counters.sol";

v5

// 削除

using Counters for Counters.Counter

v4

using Counters for Counters.Counter;
Counters.Counter private _tokenIdCounter;

v5

uint256 private _tokenIdCounter;

.current()

v4

uint256 tokenId = _tokenIdCounter.current();

v5

uint256 tokenId = _tokenIdCounter;

.increment()

v4

_tokenIdCounter.increment();

v5

_tokenIdCounter += 1;

全体

v4

import {Counters} from "@openzeppelin/contracts/utils/Counters.sol";

contract MyToken is ERC721, Pausable, Ownable {
        using Counters for Counters.Counter;
        Counters.Counter private _tokenIdCounter;

        function safeMint(address receiver) public onlyOwner {
            uint256 tokenId = _tokenIdCounter.current();
            _safeMint(_receiver, tokenId);
            _tokenIdCounter.increment();
        }
}

v5

contract MyToken is ERC721, Pausable, Ownable {
        uint256 private _tokenIdCounter;

        function safeMint(address receiver) public onlyOwner {
            uint256 tokenId = _tokenIdCounter;
            _safeMint(_receiver, tokenId);
            _tokenIdCounter += 1;
        }
}

参考記事