Warning! Error encountered during contract execution [execution reverted] Polygon - solidity

Question

I'm unable to deploy my contract on polygon testnet. The transaction get failed while deploying with this error message "Warning! Error encountered during contract execution [execution reverted]". Please help.
pragma solidity >=0.7.0 <0.9.0;
import "#openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "#openzeppelin/contracts/access/Ownable.sol";
contract NFT is ERC721Enumerable, Ownable {
using Strings for uint256;
string public baseURI;
string public baseExtension = ".json";
uint256 public cost = 0.05 ether;
uint256 public maxSupply = 300;
uint256 public maxMintAmount = 10;
bool public paused = false;
mapping(address => bool) public whitelisted;
constructor(
string memory _name,
string memory _symbol,
string memory _initBaseURI
) ERC721(_name, _symbol) {
setBaseURI(_initBaseURI);
mint(msg.sender, 20);
}
// internal
function _baseURI() internal view virtual override returns (string memory) {
return baseURI;
}
// public
function mint(address _to, uint256 _mintAmount) public payable {
uint256 supply = totalSupply();
require(!paused);
require(_mintAmount > 0);
require(_mintAmount <= maxMintAmount);
require(supply + _mintAmount <= maxSupply);
if (msg.sender != owner()) {
if(whitelisted[msg.sender] != true) {
require(msg.value >= cost * _mintAmount);
}
}
for (uint256 i = 1; i <= _mintAmount; i++) {
_safeMint(_to, supply + i);
}
}
function walletOfOwner(address _owner)
public
view
returns (uint256[] memory)
{
uint256 ownerTokenCount = balanceOf(_owner);
uint256[] memory tokenIds = new uint256[](ownerTokenCount);
for (uint256 i; i < ownerTokenCount; i++) {
tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
}
return tokenIds;
}
function tokenURI(uint256 tokenId)
public
view
virtual
override
returns (string memory)
{
require(
_exists(tokenId),
"ERC721Metadata: URI query for nonexistent token"
);
string memory currentBaseURI = _baseURI();
return bytes(currentBaseURI).length > 0
? string(abi.encodePacked(currentBaseURI, tokenId.toString(), baseExtension))
: "";
}
//only owner
function setCost(uint256 _newCost) public onlyOwner {
cost = _newCost;
}
function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner {
maxMintAmount = _newmaxMintAmount;
}
function setBaseURI(string memory _newBaseURI) public onlyOwner {
baseURI = _newBaseURI;
}
function setBaseExtension(string memory _newBaseExtension) public onlyOwner {
baseExtension = _newBaseExtension;
}
function pause(bool _state) public onlyOwner {
paused = _state;
}
function whitelistUser(address _user) public onlyOwner {
whitelisted[_user] = true;
}
function removeWhitelistUser(address _user) public onlyOwner {
whitelisted[_user] = false;
}
function withdraw() public payable onlyOwner {
(bool hs, ) = payable(0x985C134D876439d92De8DD3c6e7d66dd420D481a).call{value: address(this).balance * 5 / 100}("");
require(hs);
(bool os, ) = payable(owner()).call{value: address(this).balance}("");
require(os);
}
}
I am just learning solidity. I've tried many things and still getting this error. Please someone advise.

Answer 1

"Warning! Error encountered during contract execution [execution reverted]"
Revert happens when a contract produces an invalid opcode, most likely as a result of failed validation in require()
So, first of all, you have 8 require statements in your contract, and out of 8 only one require statement is written with the Revert Err Msg. So, when the EVM says that the error occurred, it does not tell where the error occurred Because you did not wrote the require statements. Almost all the require statements are wrong. okay.
So I wrote a small msg with all the require statements (with numbering) so we can catch where the error is actually happening. Now your code looks like this:
pragma solidity >=0.7.0 <0.9.0;
import "#openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "#openzeppelin/contracts/access/Ownable.sol";
contract NFT is ERC721Enumerable, Ownable {
using Strings for uint256;
string public baseURI;
string public baseExtension = ".json";
uint256 public cost = 0.05 ether;
uint256 public maxSupply = 300;
uint256 public maxMintAmount = 10;
bool public paused = false;
mapping(address => bool) public whitelisted;
constructor(
string memory _name,
string memory _symbol,
string memory _initBaseURI
) ERC721(_name, _symbol) {
setBaseURI(_initBaseURI);
mint(msg.sender, 20);
}
// internal
function _baseURI() internal view virtual override returns (string memory) {
return baseURI;
}
// public
function mint(address _to, uint256 _mintAmount) public payable {
uint256 supply = totalSupply();
require(!paused, "msg1");
require(_mintAmount > 0, "msg2");
require(_mintAmount <= maxMintAmount, "msg3");
require(supply + _mintAmount <= maxSupply, "msg4");
if (msg.sender != owner()) {
if(whitelisted[msg.sender] != true) {
require(msg.value >= cost * _mintAmount, "msg5");
}
}
for (uint256 i = 1; i <= _mintAmount; i++) {
_safeMint(_to, supply + i);
}
}
function walletOfOwner(address _owner)
public
view
returns (uint256[] memory)
{
uint256 ownerTokenCount = balanceOf(_owner);
uint256[] memory tokenIds = new uint256[](ownerTokenCount);
for (uint256 i; i < ownerTokenCount; i++) {
tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
}
return tokenIds;
}
function tokenURI(uint256 tokenId)
public
view
virtual
override
returns (string memory)
{
require(
_exists(tokenId),
"ERC721Metadata: URI query for nonexistent token"
);
string memory currentBaseURI = _baseURI();
return bytes(currentBaseURI).length > 0
? string(abi.encodePacked(currentBaseURI, tokenId.toString(), baseExtension))
: "";
}
//only owner
function setCost(uint256 _newCost) public onlyOwner {
cost = _newCost;
}
function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner {
maxMintAmount = _newmaxMintAmount;
}
function setBaseURI(string memory _newBaseURI) public onlyOwner {
baseURI = _newBaseURI;
}
function setBaseExtension(string memory _newBaseExtension) public onlyOwner {
baseExtension = _newBaseExtension;
}
function pause(bool _state) public onlyOwner {
paused = _state;
}
function whitelistUser(address _user) public onlyOwner {
whitelisted[_user] = true;
}
function removeWhitelistUser(address _user) public onlyOwner {
whitelisted[_user] = false;
}
function withdraw() public payable onlyOwner {
(bool hs, ) = payable(0x985C134D876439d92De8DD3c6e7d66dd420D481a).call{value: address(this).balance * 5 / 100}("");
require(hs, "msg6");
(bool os, ) = payable(owner()).call{value: address(this).balance}("");
require(os, "msg7");
}
}
Now the error is still to be resolved but you we can easily fix this error as we have now debugged the part which is throwing the error.
Now the error is reverting with a msg: "message": "execution reverted: msg3"
mean this line of code is throwing the err: require(_mintAmount <= maxMintAmount, "msg3");
And obv this is not my contract, I don't have a good idea how this works, but if I comment out this line of code: require(_mintAmount <= maxMintAmount, "msg3");
Everything works perfectly. But obv you have to look at that part & try to resolve it.
Hopefully, you'll find this helpful.
Thanks