Upbeat Coffee Badger - The rounding direction in _calcVotePrice(…) does not match the comments.

[sherlock-admin3]

Upbeat Coffee Badger

High

The rounding direction in _calcVotePrice(…) does not match the comments.

Summary

https://github.com/sherlock-audit/2024-12-ethos-update/blob/c3a2b007d0ddfcb476f300f8b766808f0e3e2dfd/ethos/packages/contracts/contracts/ReputationMarket.sol#L1003

1. Comment Meaning
   • For trust votes (isPositive = true): “round up”
   • For distrust votes (isPositive = false): “round down”
2. Actual Code Execution
   • For trust votes (isPositive = true), Math.Rounding.Floor is called (rounding down).
   • For distrust votes (isPositive = false), Math.Rounding.Ceil is called (rounding up).

This is the exact opposite of the comments, leading to the following potential issues:
1. Mismatch Between Comments and Implementation, Misleading Future Developers
Future developers or maintainers may trust the comments when reading the code or upgrading the contract, leading to misjudgments about the actual behavior and introducing further bugs.
2. Potential 1 wei Discrepancy in the Sum of Trust and Distrust Vote Prices
The original intent was for one to round up and the other to round down to ensure that trustPrice + distrustPrice ≈ basePrice. However, with the current reversed order, their sum could be slightly lower or higher than basePrice, causing cumulative “1 wei” discrepancies.
3. Conflict with Other Rounding Logic in _calcCost(…)
_calcCost(…) also contains rounding logic that mixes up buy/sell operations. If both locations confuse “positive/negative” or “buy/sell” with the rounding direction, the final price calculations will become even more inconsistent.

Root Cause

No response

Internal Pre-conditions

No response

External Pre-conditions

No response

Attack Path

No response

Impact

No response

PoC

No response

Mitigation

No response