I want to create a Uniswap Pair in a constructor() block of my token smart-contract.

However, when I try to do this, I get "error":"execution reverted".

Perhaps these nuances will help you understand what the problem is:

  • If the line with the initialization of the pair (_pair = IPan...) is commented out - code works properly.
  • This problem does not arise if the contract is deployed to Goerli, which have the same UniswapV2Router address as Mainnet. Issues occur only when i try to deploy it on Ethereum Mainnet.
  • Also, the contract is successfully deployed on the local blockchain. No errors after compilation.

Here is the address of the UniswapV2Router that I used 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D

Below is the code related directly to the interaction with Uniswap.

interface IPancakeFactory {
    function createPair(address tokenA, address tokenB) external returns (address pair);

interface IPancakePair {
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);

interface IPancakeRouter01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

interface IPancakeRouter02 is IPancakeRouter01 {}

contract MyTokenContract is Context, Ownable, IERC20 {

  IPancakeRouter02 internal _router;
  IPancakePair internal _pair;

  constructor(address _routerAddress) {
          _router = IPancakeRouter02(_routerAddress);
          _pair = IPancakePair(IPancakeFactory(_router.factory()).createPair(address(this), _router.WETH()));
          _balances[owner()] = _totalSupply;
          emit Transfer(address(0), owner(), _totalSupply);

It turns out that I simply cannot deploy a contract if a new pair is created in the constructor()

UPD: After a more detailed breakdown of the code into simple operations, I came to the conclusion that the error occurs precisely when the createPair() function is called.

Please respond if you have experienced something like this. Or have solution for this?

1 Answer 1


The problem was solved when I changed the wallet to one with more ETH (at least twice the amount that needs to be paid for fees for the deployment)

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