Function: _swapUniswapV2(byte[1] dexId, uint256 fromAmount, byte[] payload)

This decodes the payload and conducts the swaps.

Inputs

• dexId

  • Constraints: Should be either 0x01 or 0x02,

  • Impact: The ID for the DEX being used (0x01 for UniswapV2, 0x02 for SushiSwap).

• fromAmount

  • Constraints: No constraints,

  • Impact: The amount of the fromToken being swapped.

• payload

  • Constraints: Should be encoded in the correct format --- abi.encode(address[] path, uint256 minAmountOut).

  • Impact: The encoded payload for the swap.

Branches and code coverage (including function calls)

Intended branches

• The function correctly determines the initCodeHash and factory based on the dexId.

  Test coverage

• The swap ratios and amounts are calculated correctly.

  Test coverage

Negative behavior

• The function reverts if the final amountOut is less than toAmountMin.

  Negative test

Function call analysis

• _getPair(fromToken, toToken, initCodeHash, factory)

  • What is controllable? fromToken and toToken.

  • If return value controllable, how is it used and how can it go wrong? The return value is used as an address for the pair; if manipulated, it can lead to swapping on the wrong pair.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.

• IUniswapPair(pairs[i]).getReserves()

  • What is controllable? pairs[i].

  • If return value controllable, how is it used and how can it go wrong? The return value (reserveA and reserveB) impacts the calculation of swap amounts; this cannot be controlled.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.

• SafeTransferLib.safeTransfer(ERC20(path[0]), pairs[0], fromAmount)

  • What is controllable? path[0], pairs[0], and fromAmount.

  • If return value controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.

• _executeSwap(path, pairs, amounts)

  • What is controllable? path, pairs, and amounts.

  • If return value controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.