#43402 [SC-Insight] Function `getPTUnderlyingUnit` could be marked external

Submitted on Apr 5th 2025 at 15:48:56 UTC by @PotEater for Audit Comp | Spectra Finance

• Report ID: #43402

• Report Type: Smart Contract

• Report severity: Insight

• Target: https://github.com/immunefi-team/Spectra-Audit-Competition/blob/main/src/router/util/RouterUtil.sol

• Impacts:

Description

Brief/Intro

The function getPTUnderlyingUnit is marked as public, however it is not used internally anywhere, so it could be marked external to save gas.

Vulnerability details

Public functions can be called internally and externally at the same time. In such case, marking a function public would make sense. However, the mentioned functions are not used internally within the contract.

This means the functions can be marked external to save gas.

Impact Details

Functions marked public cost more gas than external functions. This is gas/code optimization.

Changing this function to external will save gas.

References

https://github.com/immunefi-team/Spectra-Audit-Competition/blob/1cebdc67a9276fd87105d13f302fd77d000d0c0b/src/router/util/RouterUtil.sol#L831

Proof of Concept

Proof of Concept

    function getPTUnderlyingUnit(address _pt) public view returns (uint256) { // @audit-issue function could be marked external
        return getUnit(IPrincipalToken(_pt).underlying());
    }