DatingDapp

Description

This report bundles two minor, low-impact issues found during the review, reported for completeness.

1. Fee truncation in matchRewards. The protocol fee is computed as matchingFees = (totalRewards * FIXEDFEE) / 100. Solidity integer division rounds down, so whenever totalRewards is not an exact multiple of 100 the sub-100-wei remainder is NOT captured as protocol fee — it stays inside rewards and is forwarded to the users. The multiply-before-divide ordering is correct (so there is no precision-loss-to-zero on realistic amounts), and the leaked value is at most 99 wei per match, i.e. economically negligible; but strictly the fee is under-collected by the rounding dust.

2. Unreachable custom-error branch in tokenURI. The guard if (ownerOf(tokenId) == address(0)) revert ERC721Metadata__URI_QueryFor_NonExistentToken(); is dead code under OpenZeppelin v5: ownerOf internally calls _requireOwned, which REVERTS with ERC721NonexistentToken for a non-existent token and never returns address(0). So the custom error can never fire, and a query for a missing token reverts with OZ's error instead. This is behaviorally safe (it reverts either way) but the branch is misleading dead code.

Risk

Likelihood:

• The fee-dust rounding occurs on any match whose total is not a multiple of 100 wei (essentially always); the dead branch is present unconditionally.

Impact:

• Negligible fee under-collection (<= 99 wei per match) and cosmetic dead code that can mislead readers/auditors. No fund loss beyond dust and no security impact — reported for completeness / code quality.

Proof of Concept

test/LikeRegistryAudit.t.sol::testFeeMathRoundsDown (PASS) shows the truncated fee and dust remaining with users. test/AuditSoulbound.t.sol::test_6_tokenURI_nonexistent_reverts_with_OZ_error_not_custom (PASS) shows tokenURI(999) reverts with ERC721NonexistentToken, not the custom error.

Recommended Mitigation

Track the fee remainder if exact accounting matters; remove the unreachable branch (or rely on OZ's revert) for clarity.