Tripathi data for issue #144

data/Tripathi-G.md

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+# Gas Optimizations
+
+
+### [G‑01] Declared variables for `mintedAmount` and `reservedRate` state variables can be avoided and mutex reset could be done after sucessful `_swap()` and `_mint()` methods- SAVE 85 gas per didPay() call
+
+Both these state variables are accessed once, gas can be saved by using them directly.
+#### In Current Logic  
+`mintedAmount` will be used once in case of (`preferClaimedTokens == true` and `_amountReceived == 0`) or 
+(`preferClaimedTokens == false`)
+
+`reservedRate` will be used once if (`preferClaimedTokens == true`) while in the case of (`preferClaimedTokens == false`) it is not used once too.
+Further without confirmation of successful `_swap()` and `_mint()` resetting the state variable from storage to 1 is itself a big factor regarding high gas, here gas can be saved by resetting them to 1 after the `_swap()` and -`_mint()` as they are not making affect to these internal methods  
+didPay() consumption of gas
+min- 51675, avg - 161126, median- 148266 and max 242106
+#### Suggested Logic
+So using these variables directly and reseting the `mutex` after `_swap()` and `_mint()` will make more sense.
+In this case `first` we will be saving gas by not declaring variable for both state variables and `second` if `preferClaimedTokens= false` there won't be any read of `reservedRate` state variables
+```solidity
+ function didPay(JBDidPayData calldata _data) external payable override {
+    // Access control as minting is authorized to this delegate
+    if (msg.sender != address(jbxTerminal)) revert JuiceBuyback_Unauthorized();
+
+    // Retrieve the number of token created if minting and reset the mutex (not exposed in JBDidPayData)
+    // uint256 _tokenCount = mintedAmount;
+    // mintedAmount = 1;
+
+    // Retrieve the fc reserved rate and reset the mutex
+    // uint256 _reservedRate = reservedRate;
+    // reservedRate = 1;
+
+    // The minimum amount of token received if swapping
+    (, , uint256 _quote, uint256 _slippage) = abi.decode(
+      _data.metadata,
+      (bytes32, bytes32, uint256, uint256)
+    );
+    uint256 _minimumReceivedFromSwap = _quote - ((_quote * _slippage) / SLIPPAGE_DENOMINATOR);
+
+    // Pick the appropriate pathway (swap vs mint), use mint if non-claimed prefered
+    if (_data.preferClaimedTokens) {
+      // Try swapping
+      uint256 _amountReceived = _swap(_data, _minimumReceivedFromSwap, reservedRate);
+
+      // If swap failed, mint instead, with the original weight + add to balance the token in
+      if (_amountReceived == 0) _mint(_data, mintedAmount);
+    } else {
+      _mint(_data, mintedAmount);
+    }
+
+    mintedAmount = 1;
+    reservedRate=1;
+  }
+```
+didPay() consumption of gas after making these changes
+min- 51580, avg - 161039, median- 148177 and max 242011
+
+by this we can save avg 85 gas per didPay() call
+
+
+*There is two instance of this issue:*
+
+```solidity
+File: juice-buyback/contracts/JBXBuybackDelegate.sol
+188:         uint256 _tokenCount = mintedAmount;
+192:         uint256 _reservedRate = reservedRate;
+```
+https://github.com/code-423n4/2023-05-juicebox/blob/9a36e5c8d0588f0f262a0cd1c08e34b2184d8f4d/juice-buyback/contracts/JBXBuybackDelegate.sol#L188
+https://github.com/code-423n4/2023-05-juicebox/blob/9a36e5c8d0588f0f262a0cd1c08e34b2184d8f4d/juice-buyback/contracts/JBXBuybackDelegate.sol#L192
+