Fix TOB-7 lack of event generation (#12318)

* Emit events for vrf v2plus state changing functions

* Emit FallbackWeiPerUnitLinkUsed event if the fallback is used in _getFeedData

* Add missing tests

* Refactor _getFeedData to return isFeedStale instead of emitting event

* Add enable, disable, and withdrawn events to VRFV2PlusWrapper

* Fix solhint and prettier

* Remove isFeedStale from VRFV2WrapperConsumerBase

* Update Solidity wrappers

contracts/src/v0.8/vrf/dev/VRFConsumerBaseV2Plus.sol

@@ -146,6 +146,8 @@ abstract contract VRFConsumerBaseV2Plus is IVRFMigratableConsumerV2Plus, Confirm
    */
   function setCoordinator(address _vrfCoordinator) public override onlyOwnerOrCoordinator {
     s_vrfCoordinator = IVRFCoordinatorV2Plus(_vrfCoordinator);
+
+    emit CoordinatorSet(_vrfCoordinator);
   }
 
   modifier onlyOwnerOrCoordinator() {

contracts/src/v0.8/vrf/dev/VRFCoordinatorV2_5.sol

@@ -98,6 +98,8 @@ contract VRFCoordinatorV2_5 is VRF, SubscriptionAPI, IVRFCoordinatorV2Plus {
     uint8 linkPremiumPercentage
   );
 
+  event FallbackWeiPerUnitLinkUsed(uint256 requestId, int256 fallbackWeiPerUnitLink);
+
   constructor(address blockhashStore) SubscriptionAPI() {
     BLOCKHASH_STORE = BlockhashStoreInterface(blockhashStore);
   }
@@ -502,10 +504,17 @@ contract VRFCoordinatorV2_5 is VRF, SubscriptionAPI, IVRFCoordinatorV2Plus {
 
     bool nativePayment = uint8(rc.extraArgs[rc.extraArgs.length - 1]) == 1;
 
-    // We want to charge users exactly for how much gas they use in their callback.
-    // The gasAfterPaymentCalculation is meant to cover these additional operations where we
-    // decrement the subscription balance and increment the oracles withdrawable balance.
-    payment = _calculatePaymentAmount(startGas, gasPrice, nativePayment, onlyPremium);
+    // stack too deep error
+    {
+      // We want to charge users exactly for how much gas they use in their callback.
+      // The gasAfterPaymentCalculation is meant to cover these additional operations where we
+      // decrement the subscription balance and increment the oracles withdrawable balance.
+      bool isFeedStale;
+      (payment, isFeedStale) = _calculatePaymentAmount(startGas, gasPrice, nativePayment, onlyPremium);
+      if (isFeedStale) {
+        emit FallbackWeiPerUnitLinkUsed(output.requestId, s_fallbackWeiPerUnitLink);
+      }
+    }
 
     _chargePayment(payment, nativePayment, rc.subId);
 
@@ -539,9 +548,9 @@ contract VRFCoordinatorV2_5 is VRF, SubscriptionAPI, IVRFCoordinatorV2Plus {
     uint256 weiPerUnitGas,
     bool nativePayment,
     bool onlyPremium
-  ) internal view returns (uint96) {
+  ) internal view returns (uint96, bool) {
     if (nativePayment) {
-      return _calculatePaymentAmountNative(startGas, weiPerUnitGas, onlyPremium);
+      return (_calculatePaymentAmountNative(startGas, weiPerUnitGas, onlyPremium), false);
     }
     return _calculatePaymentAmountLink(startGas, weiPerUnitGas, onlyPremium);
   }
@@ -569,9 +578,8 @@ contract VRFCoordinatorV2_5 is VRF, SubscriptionAPI, IVRFCoordinatorV2Plus {
     uint256 startGas,
     uint256 weiPerUnitGas,
     bool onlyPremium
-  ) internal view returns (uint96) {
-    int256 weiPerUnitLink;
-    weiPerUnitLink = _getFeedData();
+  ) internal view returns (uint96, bool) {
+    (int256 weiPerUnitLink, bool isFeedStale) = _getFeedData();
     if (weiPerUnitLink <= 0) {
       revert InvalidLinkWeiPrice(weiPerUnitLink);
     }
@@ -594,18 +602,19 @@ contract VRFCoordinatorV2_5 is VRF, SubscriptionAPI, IVRFCoordinatorV2Plus {
     if (payment > 1e27) {
       revert PaymentTooLarge(); // Payment + fee cannot be more than all of the link in existence.
     }
-    return uint96(payment);
+    return (uint96(payment), isFeedStale);
   }
 
-  function _getFeedData() private view returns (int256 weiPerUnitLink) {
+  function _getFeedData() private view returns (int256 weiPerUnitLink, bool isFeedStale) {
     uint32 stalenessSeconds = s_config.stalenessSeconds;
     uint256 timestamp;
     (, weiPerUnitLink, , timestamp, ) = LINK_NATIVE_FEED.latestRoundData();
     // solhint-disable-next-line not-rely-on-time
-    if (stalenessSeconds > 0 && stalenessSeconds < block.timestamp - timestamp) {
+    isFeedStale = stalenessSeconds > 0 && stalenessSeconds < block.timestamp - timestamp;
+    if (isFeedStale) {
       weiPerUnitLink = s_fallbackWeiPerUnitLink;
     }
-    return weiPerUnitLink;
+    return (weiPerUnitLink, isFeedStale);
   }
 
   /**

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

@@ -152,9 +152,11 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     if (address(s_link) != address(0)) {
       revert LinkAlreadySet();
     }
-    s_link = LinkTokenInterface(link);
 
+    s_link = LinkTokenInterface(link);
     s_linkNativeFeed = AggregatorV3Interface(linkNativeFeed);
+
+    emit LinkAndLinkNativeFeedSet(link, linkNativeFeed);
   }
 
   /**
@@ -163,6 +165,8 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
    */
   function setFulfillmentTxSize(uint32 size) external onlyOwner {
     s_fulfillmentTxSizeBytes = size;
+
+    emit FulfillmentTxSizeSet(size);
   }
 
   /**
@@ -216,6 +220,18 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     s_fallbackWeiPerUnitLink = _fallbackWeiPerUnitLink;
     s_fulfillmentFlatFeeLinkPPM = _fulfillmentFlatFeeLinkPPM;
     s_fulfillmentFlatFeeNativePPM = _fulfillmentFlatFeeNativePPM;
+
+    emit ConfigSet(
+      _wrapperGasOverhead,
+      _coordinatorGasOverhead,
+      _wrapperPremiumPercentage,
+      _keyHash,
+      _maxNumWords,
+      _stalenessSeconds,
+      _fallbackWeiPerUnitLink,
+      _fulfillmentFlatFeeLinkPPM,
+      _fulfillmentFlatFeeNativePPM
+    );
   }
 
   /**
@@ -288,7 +304,7 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
   function calculateRequestPrice(
     uint32 _callbackGasLimit
   ) external view override onlyConfiguredNotDisabled returns (uint256) {
-    int256 weiPerUnitLink = _getFeedData();
+    (int256 weiPerUnitLink, ) = _getFeedData();
     return _calculateRequestPrice(_callbackGasLimit, tx.gasprice, weiPerUnitLink);
   }
 
@@ -311,7 +327,7 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     uint32 _callbackGasLimit,
     uint256 _requestGasPriceWei
   ) external view override onlyConfiguredNotDisabled returns (uint256) {
-    int256 weiPerUnitLink = _getFeedData();
+    (int256 weiPerUnitLink, ) = _getFeedData();
     return _calculateRequestPrice(_callbackGasLimit, _requestGasPriceWei, weiPerUnitLink);
   }
 
@@ -385,7 +401,7 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     );
     checkPaymentMode(extraArgs, true);
     uint32 eip150Overhead = _getEIP150Overhead(callbackGasLimit);
-    int256 weiPerUnitLink = _getFeedData();
+    (int256 weiPerUnitLink, bool isFeedStale) = _getFeedData();
     uint256 price = _calculateRequestPrice(callbackGasLimit, tx.gasprice, weiPerUnitLink);
     // solhint-disable-next-line custom-errors
     require(_amount >= price, "fee too low");
@@ -406,6 +422,10 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
       requestGasPrice: uint64(tx.gasprice)
     });
     lastRequestId = requestId;
+
+    if (isFeedStale) {
+      emit FallbackWeiPerUnitLinkUsed(requestId, s_fallbackWeiPerUnitLink);
+    }
   }
 
   function checkPaymentMode(bytes memory extraArgs, bool isLinkMode) public pure {
@@ -470,9 +490,12 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
    * @param _recipient is the address that should receive the LINK funds.
    */
   function withdraw(address _recipient) external onlyOwner {
-    if (!s_link.transfer(_recipient, s_link.balanceOf(address(this)))) {
+    uint256 amount = s_link.balanceOf(address(this));
+    if (!s_link.transfer(_recipient, amount)) {
       revert FailedToTransferLink();
     }
+
+    emit Withdrawn(_recipient, amount);
   }
 
   /**
@@ -481,16 +504,21 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
    * @param _recipient is the address that should receive the native funds.
    */
   function withdrawNative(address _recipient) external onlyOwner {
-    (bool success, ) = payable(_recipient).call{value: address(this).balance}("");
+    uint256 amount = address(this).balance;
+    (bool success, ) = payable(_recipient).call{value: amount}("");
     // solhint-disable-next-line custom-errors
     require(success, "failed to withdraw native");
+
+    emit NativeWithdrawn(_recipient, amount);
   }
 
   /**
    * @notice enable this contract so that new requests can be accepted.
    */
   function enable() external onlyOwner {
     s_disabled = false;
+
+    emit Enabled();
   }
 
   /**
@@ -499,6 +527,8 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
    */
   function disable() external onlyOwner {
     s_disabled = true;
+
+    emit Disabled();
   }
 
   // solhint-disable-next-line chainlink-solidity/prefix-internal-functions-with-underscore
@@ -517,18 +547,18 @@ contract VRFV2PlusWrapper is ConfirmedOwner, TypeAndVersionInterface, VRFConsume
     }
   }
 
-  function _getFeedData() private view returns (int256) {
-    bool staleFallback = s_stalenessSeconds > 0;
+  function _getFeedData() private view returns (int256 weiPerUnitLink, bool isFeedStale) {
+    uint32 stalenessSeconds = s_stalenessSeconds;
     uint256 timestamp;
-    int256 weiPerUnitLink;
     (, weiPerUnitLink, , timestamp, ) = s_linkNativeFeed.latestRoundData();
     // solhint-disable-next-line not-rely-on-time
-    if (staleFallback && s_stalenessSeconds < block.timestamp - timestamp) {
+    isFeedStale = stalenessSeconds > 0 && stalenessSeconds < block.timestamp - timestamp;
+    if (isFeedStale) {
       weiPerUnitLink = s_fallbackWeiPerUnitLink;
     }
     // solhint-disable-next-line custom-errors
     require(weiPerUnitLink >= 0, "Invalid LINK wei price");
-    return weiPerUnitLink;
+    return (weiPerUnitLink, isFeedStale);
   }
 
   /**

contracts/src/v0.8/vrf/dev/VRFV2PlusWrapperConsumerBase.sol

@@ -29,6 +29,8 @@ import {IVRFV2PlusWrapper} from "./interfaces/IVRFV2PlusWrapper.sol";
  * @dev fulfillment with the randomness result.
  */
 abstract contract VRFV2PlusWrapperConsumerBase {
+  event LinkTokenSet(address link);
+
   error LINKAlreadySet();
   error OnlyVRFWrapperCanFulfill(address have, address want);
 
@@ -57,6 +59,8 @@ abstract contract VRFV2PlusWrapperConsumerBase {
     }
 
     s_linkToken = LinkTokenInterface(_link);
+
+    emit LinkTokenSet(_link);
   }
 
   /**

contracts/src/v0.8/vrf/dev/interfaces/IVRFMigratableConsumerV2Plus.sol

@@ -5,6 +5,8 @@ pragma solidity ^0.8.0;
 /// @notice method required to be implemented by all V2Plus consumers.
 /// @dev This interface is designed to be used in VRFConsumerBaseV2Plus.
 interface IVRFMigratableConsumerV2Plus {
+  event CoordinatorSet(address vrfCoordinator);
+
   /// @notice Sets the VRF Coordinator address
   /// @notice This method is should only be callable by the coordinator or contract owner
   function setCoordinator(address vrfCoordinator) external;

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

@@ -2,6 +2,25 @@
 pragma solidity ^0.8.0;
 
 interface IVRFV2PlusWrapper {
+  event LinkAndLinkNativeFeedSet(address link, address linkNativeFeed);
+  event FulfillmentTxSizeSet(uint32 size);
+  event ConfigSet(
+    uint32 wrapperGasOverhead,
+    uint32 coordinatorGasOverhead,
+    uint8 wrapperPremiumPercentage,
+    bytes32 keyHash,
+    uint8 maxNumWords,
+    uint32 stalenessSeconds,
+    int256 fallbackWeiPerUnitLink,
+    uint32 fulfillmentFlatFeeLinkPPM,
+    uint32 fulfillmentFlatFeeNativePPM
+  );
+  event FallbackWeiPerUnitLinkUsed(uint256 requestId, int256 fallbackWeiPerUnitLink);
+  event Withdrawn(address indexed to, uint256 amount);
+  event NativeWithdrawn(address indexed to, uint256 amount);
+  event Enabled();
+  event Disabled();
+
   /**
    * @return the request ID of the most recent VRF V2 request made by this wrapper. This should only
    * be relied option within the same transaction that the request was made.

contracts/src/v0.8/vrf/dev/testhelpers/ExposedVRFCoordinatorV2_5.sol

@@ -71,7 +71,7 @@ contract ExposedVRFCoordinatorV2_5 is VRFCoordinatorV2_5 {
     uint256 weiPerUnitGas,
     bool nativePayment,
     bool onlyPremium
-  ) external view returns (uint96) {
+  ) external view returns (uint96, bool) {
     return _calculatePaymentAmount(startGas, weiPerUnitGas, nativePayment, onlyPremium);
   }
 }

contracts/test/v0.8/foundry/vrf/VRFV2Plus.t.sol

@@ -363,6 +363,7 @@ contract VRFV2Plus is BaseTest {
     bytes extraArgs,
     bool success
   );
+  event FallbackWeiPerUnitLinkUsed(uint256 requestId, int256 fallbackWeiPerUnitLink);
 
   function testRequestAndFulfillRandomWordsNative() public {
     (
@@ -449,6 +450,27 @@ contract VRFV2Plus is BaseTest {
     assertApproxEqAbs(linkBalanceAfter, linkBalanceBefore - 8.3234 * 1e17, 1e15);
   }
 
+  function testRequestAndFulfillRandomWordsLINK_FallbackWeiPerUnitLinkUsed() public {
+    (
+      VRF.Proof memory proof,
+      VRFCoordinatorV2_5.RequestCommitment memory rc,
+      ,
+      uint256 requestId
+    ) = setupSubAndRequestRandomnessLINKPayment();
+
+    (, , , uint32 stalenessSeconds, , , , , ) = s_testCoordinator.s_config();
+    int256 fallbackWeiPerUnitLink = s_testCoordinator.s_fallbackWeiPerUnitLink();
+
+    // Set the link feed to be stale.
+    (uint80 roundId, int256 answer, uint256 startedAt, , ) = s_linkNativeFeed.latestRoundData();
+    uint256 timestamp = block.timestamp - stalenessSeconds - 1;
+    s_linkNativeFeed.updateRoundData(roundId, answer, timestamp, startedAt);
+
+    vm.expectEmit(false, false, false, true, address(s_testCoordinator));
+    emit FallbackWeiPerUnitLinkUsed(requestId, fallbackWeiPerUnitLink);
+    s_testCoordinator.fulfillRandomWords(proof, rc, false);
+  }
+
   function setupSubAndRequestRandomnessLINKPayment()
     internal
     returns (VRF.Proof memory proof, VRFCoordinatorV2_5.RequestCommitment memory rc, uint256 subId, uint256 requestId)