ahayashi-Q.md

[NC-AH-01] Use byte32(0) instead of byte23(0)

Summary

merkleRoot is defined as bytes32 type but it is compared to bytes23(0).

This is a different issue from the one noted in GAS-2 though it could be resolved by reflecting the GAS-2 remarks, but may not do so for readability.

Lines

File: src/Pair.sol

25:  bytes32 public immutable merkleRoot;

465:  if (merkleRoot == bytes23(0)) return;

[NC-AH-02] Use a clearer constant name

Summary

The use of ONE as a constant name for the amount of fractional tokens per NFT is confusing, so it should be named clearer like FRACTIONAL_TOKEN_AMOUNT_PER_NFT.

Lines

File: src/Pair.sol

20:  uint256 public constant ONE = 1e18;

[NC-AH-03] Add indexed fields to event

Summary

A parameter is stored as topic by adding indexed to it and off-chain tools can quickly analyze it.

Lines

File: src/Pair.sol

30:    event Add(uint256 baseTokenAmount, uint256 fractionalTokenAmount, uint256 lpTokenAmount);
31:    event Remove(uint256 baseTokenAmount, uint256 fractionalTokenAmount, uint256 lpTokenAmount);
32:    event Buy(uint256 inputAmount, uint256 outputAmount);
33:    event Sell(uint256 inputAmount, uint256 outputAmount);
34:    event Wrap(uint256[] tokenIds);
35:    event Unwrap(uint256[] tokenIds);
36:    event Close(uint256 closeTimestamp);
37:    event Withdraw(uint256 tokenId);

File: src/Caviar.sol

30:    event Add(uint256 baseTokenAmount, uint256 fractionalTokenAmount, uint256 lpTokenAmount);
31:    event Remove(uint256 baseTokenAmount, uint256 fractionalTokenAmount, uint256 lpTokenAmount);
32:    event Buy(uint256 inputAmount, uint256 outputAmount);
33:    event Sell(uint256 inputAmount, uint256 outputAmount);
34:    event Wrap(uint256[] tokenIds);
35:    event Unwrap(uint256[] tokenIds);
36:    event Close(uint256 closeTimestamp);
37:    event Withdraw(uint256 tokenId);

[NC-AH-04] wrap, unwrap, nftBuy and nftSell can be called with a empty tokenIds

Summary

They can also be called from the demo app.

[NC-AH-05] zero amount of base token can be transferred

Summary

buy method can be called with buy(0, 0) and zero amount transfer is executed at L172.

Same goes with sell method.

Lines

File: src/Pair.sol

172:  ERC20(baseToken).safeTransferFrom(msg.sender, address(this), inputAmount);

[L-AH-01] BaseToken cannot be withdrawn if LP token is lost.

Summary

The baseToken sent to Pair contract by the add method can only be retrieved by calling the remove method; if the LP token is sent to a zero address, for example, the baseToken cannot be retrieved.

This is a valid issue because the doc does't say about LP token is stuck.