Improve various comments (#908)

Improve comments

src/PoolManager.sol

@@ -341,6 +341,7 @@ contract PoolManager is IPoolManager, ProtocolFees, NoDelegateCall, ERC6909Claim
         _pools[id].setLPFee(newDynamicLPFee);
     }
 
+    // if settling native, integrators should still call `sync` first to avoid DoS attack vectors
     function _settle(address recipient) internal returns (uint256 paid) {
         Currency currency = CurrencyReserves.getSyncedCurrency();
 

src/interfaces/IHooks.sol

@@ -78,7 +78,7 @@ interface IHooks {
     /// @param sender The initial msg.sender for the remove liquidity call
     /// @param key The key for the pool
     /// @param params The parameters for removing liquidity
-    /// @param delta The caller's balance delta after adding liquidity; the sum of principal delta, fees accrued, and hook delta
+    /// @param delta The caller's balance delta after removing liquidity; the sum of principal delta, fees accrued, and hook delta
     /// @param feesAccrued The fees accrued since the last time fees were collected from this position
     /// @param hookData Arbitrary data handed into the PoolManager by the liquidity provider to be be passed on to the hook
     /// @return bytes4 The function selector for the hook

src/interfaces/IPoolManager.sol

@@ -186,7 +186,8 @@ interface IPoolManager is IProtocolFees, IERC6909Claims, IExtsload, IExttload {
     function sync(Currency currency) external;
 
     /// @notice Called by the user to net out some value owed to the user
-    /// @dev Can also be used as a mechanism for _free_ flash loans
+    /// @dev Will revert if the requested amount is not available, consider using `mint` instead
+    /// @dev Can also be used as a mechanism for free flash loans
     /// @param currency The currency to withdraw from the pool manager
     /// @param to The address to withdraw to
     /// @param amount The amount of currency to withdraw

src/libraries/Hooks.sol

@@ -159,7 +159,7 @@ library Hooks {
     function callHookWithReturnDelta(IHooks self, bytes memory data, bool parseReturn) internal returns (int256) {
         bytes memory result = callHook(self, data);
 
-        // If this hook wasnt meant to return something, default to 0 delta
+        // If this hook wasn't meant to return something, default to 0 delta
         if (!parseReturn) return 0;
 
         // A length of 64 bytes is required to return a bytes4, and a 32 byte delta
@@ -258,7 +258,8 @@ library Hooks {
             // A length of 96 bytes is required to return a bytes4, a 32 byte delta, and an LP fee
             if (result.length != 96) InvalidHookResponse.selector.revertWith();
 
-            // dynamic fee pools that do not want to override the cache fee, return 0 otherwise they return a valid fee with the override flag
+            // dynamic fee pools that want to override the cache fee, return a valid fee with the override flag. If override flag
+            // is set but an invalid fee is returned, the transaction will revert. Otherwise the current LP fee will be used
             if (key.fee.isDynamicFee()) lpFeeOverride = result.parseFee();
 
             // skip this logic for the case where the hook return is 0

src/libraries/LPFeeLibrary.sol

@@ -11,7 +11,7 @@ library LPFeeLibrary {
     /// @notice Thrown when the static or dynamic fee on a pool exceeds 100%.
     error LPFeeTooLarge(uint24 fee);
 
-    /// @notice An lp fee of exactly 0b1000000... signals a dynamic fee pool. This isnt a valid static fee as it is > MAX_LP_FEE
+    /// @notice An lp fee of exactly 0b1000000... signals a dynamic fee pool. This isn't a valid static fee as it is > MAX_LP_FEE
     uint24 public constant DYNAMIC_FEE_FLAG = 0x800000;
 
     /// @notice the second bit of the fee returned by beforeSwap is used to signal if the stored LP fee should be overridden in this swap

src/libraries/Pool.sol

@@ -535,7 +535,8 @@ library Pool {
             }
         }
 
-        // when the lower (upper) tick is crossed left to right (right to left), liquidity must be added (removed)
+        // when the lower (upper) tick is crossed left to right, liquidity must be added (removed)
+        // when the lower (upper) tick is crossed right to left, liquidity must be removed (added)
         int128 liquidityNet = upper ? liquidityNetBefore - liquidityDelta : liquidityNetBefore + liquidityDelta;
         assembly ("memory-safe") {
             // liquidityGrossAfter and liquidityNet are packed in the first slot of `info`
@@ -561,6 +562,7 @@ library Pool {
     function tickSpacingToMaxLiquidityPerTick(int24 tickSpacing) internal pure returns (uint128 result) {
         // Equivalent to:
         // int24 minTick = (TickMath.MIN_TICK / tickSpacing);
+        // if (TickMath.MIN_TICK  % tickSpacing != 0) minTick--;
         // int24 maxTick = (TickMath.MAX_TICK / tickSpacing);
         // uint24 numTicks = maxTick - minTick + 1;
         // return type(uint128).max / numTicks;

src/libraries/UnsafeMath.sol

@@ -5,7 +5,7 @@ pragma solidity ^0.8.0;
 /// @notice Contains methods that perform common math functions but do not do any overflow or underflow checks
 library UnsafeMath {
     /// @notice Returns ceil(x / y)
-    /// @dev division by 0 has unspecified behavior, and must be checked externally
+    /// @dev division by 0 will return 0, and should be checked externally
     /// @param x The dividend
     /// @param y The divisor
     /// @return z The quotient, ceil(x / y)
@@ -16,7 +16,7 @@ library UnsafeMath {
     }
 
     /// @notice Calculates floor(a×b÷denominator)
-    /// @dev division by 0 has unspecified behavior, and must be checked externally
+    /// @dev division by 0 will return 0, and should be checked externally
     /// @param a The multiplicand
     /// @param b The multiplier
     /// @param denominator The divisor

test/CustomAccounting.t.sol

@@ -254,7 +254,7 @@ contract CustomAccountingTest is Test, Deployers, GasSnapshot {
                     "manager balance change exact input"
                 );
 
-                // exact output, where there isnt enough output reserves available to pay swap and hook
+                // exact output, where there isn't enough output reserves available to pay swap and hook
             } else if (!isExactIn && (hookDeltaSpecified + amountSpecified > maxPossibleOut_fuzz_test)) {
                 // the hook will have taken hookDeltaSpecified of the maxPossibleOut
                 assertEq(deltaSpecified, maxPossibleOut_fuzz_test - hookDeltaSpecified, "deltaSpecified exact output");