FlatPosition3 Manual Review Findings

FP3-01M: Improper Rounding of Nearest Tick

Type	Severity	Location
Mathematical Operations		FlatPosition3.sol:L28

Description:

The FlatPosition3::calculatePosition function will improperly round negative ticks toward 0, resulting in liquidity deployment that is slightly out-of-range.

Impact:

Simplified, the current system is meant to deploy liquidity around the current tick (i.e. for tick spacing 1 and active tick 2.5, the system deploys liquidity to the [1,3] range).

Due to how negative number rounding works, the system would deploy liquidity incorrectly for the negative counterpart of 2.5 (i.e. for -2.5, the system will presently deploy liquidity to [-3, -1] instead of [-4, -2]).

Example:

Copy
28int24 nearestTickMultiple = (currentTick / tickSpacing) * tickSpacing;
29int24 lowerTick = nearestTickMultiple - tickSpacing;
30int24 upperTick = nearestTickMultiple + tickSpacing;

Recommendation:

We advise the nearest tick multiple to be calculated whilst rounding toward negative infinity, ensuring that the liquidity deployment performed is optimal.

Alleviation:

The code was updated to round toward the nearest tick properly, alleviating this exhibit.