Set LINK native feed in VRFV2PlusWrapper to immutable (#12592)

* Set LINK native feed in VRFV2PlusWrapper to immutable

* LINK native feed set to immutable, removed setter function
* both LINK token and LINK native feed can be set to zero addresses
* fixed Foundry tests

* Added solhint disable for LINK_NATIVE_FEED immutable var

* Added changesets

* Delete storage slot padding from VRFV2PlusWrapper

Co-authored-by: Lee Yik Jiun <yikjiun.lee@smartcontract.com>

* Renamed LINK_NATIVE_FEED to i_link_native_feed, generated Go wrappers

* Fixed linter issue

* Link native feed address variable set to internal

---------

Co-authored-by: Lee Yik Jiun <yikjiun.lee@smartcontract.com>

.changeset/odd-mugs-divide.md

@@ -0,0 +1,5 @@
+---
+"chainlink": patch
+---
+
+Set LINK native feed in VRFV2PlusWrapper to immutable

contracts/.changeset/strange-actors-do.md

@@ -0,0 +1,5 @@
+---
+"@chainlink/contracts": patch
+---
+
+Set LINK native feed in VRFV2PlusWrapper to immutable

contracts/src/v0.8/vrf/dev/VRFV2PlusWrapper.sol

@@ -30,6 +30,7 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
   // solhint-disable-next-line chainlink-solidity/prefix-immutable-variables-with-i
   uint256 public immutable SUBSCRIPTION_ID;
   LinkTokenInterface internal immutable i_link;
+  AggregatorV3Interface internal immutable i_link_native_feed;
 
   error LinkAlreadySet();
   error LinkDiscountTooHigh(uint32 flatFeeLinkDiscountPPM, uint32 flatFeeNativePPM);
@@ -80,13 +81,6 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
   // fallback to fallbackWeiPerUnitLink.
   uint32 private s_stalenessSeconds;
 
-  AggregatorV3Interface public s_linkNativeFeed;
-
-  /// @dev padding to make sure that the next variable is at a new storage slot
-  uint64 private s_padding;
-  /* Storage Slot 5: END */
-
-  /* Storage Slot 6: BEGIN */
   // s_wrapperGasOverhead reflects the gas overhead of the wrapper's fulfillRandomWords
   // function. The cost for this gas is passed to the user.
   uint32 private s_wrapperGasOverhead;
@@ -125,8 +119,8 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
   // Wrapper has no premium. This premium is for VRFCoordinator.
   uint8 private s_coordinatorLinkPremiumPercentage;
 
-  // 10 bytes left
-  /* Storage Slot 6: END */
+  // 6 bytes left
+  /* Storage Slot 5: END */
 
   struct Callback {
     address callbackAddress;
@@ -137,24 +131,19 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     // GasPrice is unlikely to be more than 14 ETH on most chains
     uint64 requestGasPrice;
   }
-  /* Storage Slot 7: BEGIN */
+  /* Storage Slot 6: BEGIN */
   mapping(uint256 => Callback) /* requestID */ /* callback */ public s_callbacks;
-  /* Storage Slot 7: END */
+  /* Storage Slot 6: END */
 
   constructor(
     address _link,
     address _linkNativeFeed,
     address _coordinator,
     uint256 _subId
   ) VRFConsumerBaseV2Plus(_coordinator) {
-    if (_link == address(0)) {
-      revert ZeroAddress();
-    }
     i_link = LinkTokenInterface(_link);
+    i_link_native_feed = AggregatorV3Interface(_linkNativeFeed);
 
-    if (_linkNativeFeed != address(0)) {
-      s_linkNativeFeed = AggregatorV3Interface(_linkNativeFeed);
-    }
     if (_subId == 0) {
       revert SubscriptionIdMissing();
     }
@@ -170,16 +159,6 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     SUBSCRIPTION_ID = _subId;
   }
 
-  /**
-   * @notice set link native feed to be used by this wrapper
-   * @param linkNativeFeed address of the link native feed
-   */
-  function setLinkNativeFeed(address linkNativeFeed) external onlyOwner {
-    s_linkNativeFeed = AggregatorV3Interface(linkNativeFeed);
-
-    emit LinkNativeFeedSet(linkNativeFeed);
-  }
-
   /**
    * @notice setFulfillmentTxSize sets the size of the fulfillment transaction in bytes.
    * @param size is the size of the fulfillment transaction in bytes.
@@ -599,10 +578,14 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     return address(i_link);
   }
 
+  function linkNativeFeed() external view override returns (address) {
+    return address(i_link_native_feed);
+  }
+
   function _getFeedData() private view returns (int256 weiPerUnitLink, bool isFeedStale) {
     uint32 stalenessSeconds = s_stalenessSeconds;
     uint256 timestamp;
-    (, weiPerUnitLink, , timestamp, ) = s_linkNativeFeed.latestRoundData();
+    (, weiPerUnitLink, , timestamp, ) = i_link_native_feed.latestRoundData();
     // solhint-disable-next-line not-rely-on-time
     isFeedStale = stalenessSeconds > 0 && stalenessSeconds < block.timestamp - timestamp;
     if (isFeedStale) {

contracts/src/v0.8/vrf/dev/interfaces/IVRFV2PlusWrapper.sol

@@ -2,7 +2,6 @@
 pragma solidity ^0.8.0;
 
 interface IVRFV2PlusWrapper {
-  event LinkNativeFeedSet(address linkNativeFeed);
   event FulfillmentTxSizeSet(uint32 size);
   event ConfigSet(
     uint32 wrapperGasOverhead,
@@ -90,4 +89,5 @@ interface IVRFV2PlusWrapper {
   ) external payable returns (uint256 requestId);
 
   function link() external view returns (address);
+  function linkNativeFeed() external view returns (address);
 }

contracts/test/v0.8/foundry/vrf/VRFV2PlusWrapper.t.sol

@@ -51,6 +51,8 @@ contract VRFV2PlusWrapperTest is BaseTest {
       address(s_testCoordinator),
       uint256(s_wrapperSubscriptionId)
     );
+    assertEq(address(s_linkToken), address(s_wrapper.link()));
+    assertEq(address(s_linkNativeFeed), address(s_wrapper.linkNativeFeed()));
 
     // Add wrapper as a consumer to the wrapper's subscription.
     s_testCoordinator.addConsumer(uint256(s_wrapperSubscriptionId), address(s_wrapper));
@@ -156,14 +158,14 @@ contract VRFV2PlusWrapperTest is BaseTest {
 
   function testVRFV2PlusWrapperZeroAddress() public {
     vm.expectRevert(VRFConsumerBaseV2Plus.ZeroAddress.selector);
-    new VRFV2PlusWrapper(address(s_linkToken), address(0), address(0), uint256(0));
+    new VRFV2PlusWrapper(address(s_linkToken), address(s_linkNativeFeed), address(0), uint256(0));
   }
 
   function testCreationOfANewVRFV2PlusWrapper() public {
     // second wrapper contract will simply add itself to the same subscription
     VRFV2PlusWrapper nextWrapper = new VRFV2PlusWrapper(
       address(s_linkToken),
-      address(0),
+      address(s_linkNativeFeed),
       address(s_testCoordinator),
       s_wrapperSubscriptionId
     );
@@ -172,27 +174,12 @@ contract VRFV2PlusWrapperTest is BaseTest {
 
   function testVRFV2PlusWrapperWithZeroSubscriptionId() public {
     vm.expectRevert(VRFV2PlusWrapper.SubscriptionIdMissing.selector);
-    new VRFV2PlusWrapper(address(s_linkToken), address(0), address(s_testCoordinator), uint256(0));
+    new VRFV2PlusWrapper(address(s_linkToken), address(s_linkNativeFeed), address(s_testCoordinator), uint256(0));
   }
 
   function testVRFV2PlusWrapperWithInvalidSubscriptionId() public {
     vm.expectRevert(SubscriptionAPI.InvalidSubscription.selector);
-    new VRFV2PlusWrapper(address(s_linkToken), address(0), address(s_testCoordinator), uint256(123456));
-  }
-
-  function testSetLinkAndLinkNativeFeed() public {
-    VRFV2PlusWrapper wrapper = new VRFV2PlusWrapper(
-      address(s_linkToken),
-      address(0),
-      address(s_testCoordinator),
-      uint256(s_wrapperSubscriptionId)
-    );
-
-    // Set LINK/Native feed on wrapper.
-    vm.expectEmit(false, false, false, true, address(wrapper));
-    emit LinkNativeFeedSet(address(s_linkNativeFeed));
-    wrapper.setLinkNativeFeed(address(s_linkNativeFeed));
-    assertEq(address(wrapper.s_linkNativeFeed()), address(s_linkNativeFeed));
+    new VRFV2PlusWrapper(address(s_linkToken), address(s_linkNativeFeed), address(s_testCoordinator), uint256(123456));
   }
 
   function testSetFulfillmentTxSize() public {