LimitOrderHook: review notes

[luiz-lvj]

Grouping a set of observations about LimitOrderHook in one place, for tracking and to reduce duplicate reports. Items are summarized briefly and are not all confirmed. No severity is assigned here.

- Withdrawal accounting can underflow — withdraw computes currency*Total - checkpoint while currency*Total is decremented on each withdrawal, so an earlier withdrawal can push a total below a later user's checkpoint and block that withdrawal. Already tracked in #129. #138
- Final cancel clears order totals — On the last cancel, order totals are zeroed without redeeming fee claims minted to the hook by earlier partial cancels, leaving those claims unaccounted. Already tracked in #127. #138
- Checkpoint set before fee realization — A placement records its checkpoint from current totals before modifyLiquidity credits previously accrued fees, so newly added liquidity can share fees accrued before it joined. #138
- Boundary fills can be skipped — The tick is derived from sqrtPriceX96 rather than slot0.tick; at an exact boundary on a downward move the order at that tick can be left unfilled, so withdraw reverts NotFilled until price re-enters. #153
- PoolKey.hooks not validated — placeOrder/cancelOrder accept a caller-supplied PoolKey without checking key.hooks == address(this), so orders can be placed against pools configured with a different hook. #149
- In-range check based on deltas — Out-of-range placement is inferred from balance-delta zero-checks rather than comparing the current tick to the order range, so a boundary placement with a one-sided principal can create in-range liquidity. #149
- Fill crediting the deposited token (tickSpacing = 1) — Already tracked in #132. #153
- Native currency order settlement — Native-currency settlement can spend the hook's own ETH rather than the intended payer. #154

• Per-swap tick scan — afterSwap iterates every crossed tick in tickSpacing steps calling _fillOrder, so gas scales with the size of the tick move and a wide swap can revert. See LimitOrderHook: L-08 scan only the ticks that hold an order #150
• Per-swap fill cost scales with orders crossed — Each crossed order is filled with a modifyLiquidity removal, around 123k gas, with no cap and no minimum order size, so a swap crossing a dense range can revert.

Source: src/general/LimitOrderHook.sol.