chore: use custom errors

Signed-off-by: Tomás Migone <[email protected]>

Author: tmigone

packages/horizon/contracts/interfaces/internal/IHorizonStakingMain.sol

@@ -471,6 +471,11 @@ interface IHorizonStakingMain {
      */
     error HorizonStakingTooManyThawRequests();
 
+    /**
+     * @notice Thrown when attempting to withdraw tokens that have not thawed (legacy undelegate).
+     */
+    error HorizonStakingNothingToWithdraw();
+
     // -- Errors: misc --
     /**
      * @notice Thrown during the transition period when attempting to withdraw tokens that are still thawing.
@@ -498,6 +503,11 @@ interface IHorizonStakingMain {
      */
     error HorizonStakingInvalidDelegationFeeCut(uint256 feeCut);
 
+    /**
+     * @notice Thrown when a legacy slash fails.
+     */
+    error HorizonStakingLegacySlashFailed();
+
     // -- Functions --
 
     /**
@@ -972,4 +982,10 @@ interface IHorizonStakingMain {
      * @return Whether the operator is authorized or not
      */
     function isAuthorized(address serviceProvider, address verifier, address operator) external view returns (bool);
+
+    /**
+     * @notice Get the address of the staking extension.
+     * @return The address of the staking extension
+     */
+    function getStakingExtension() external view returns (address);
 }

packages/horizon/contracts/staking/HorizonStaking.sol

@@ -361,7 +361,7 @@ contract HorizonStaking is HorizonStakingBase, IHorizonStakingMain {
         ) {
             tokensToWithdraw = delegation.__DEPRECATED_tokensLocked;
         }
-        require(tokensToWithdraw > 0, "!tokens");
+        require(tokensToWithdraw > 0, HorizonStakingNothingToWithdraw());
 
         // Reset lock
         delegation.__DEPRECATED_tokensLocked = 0;
@@ -402,7 +402,7 @@ contract HorizonStaking is HorizonStakingBase, IHorizonStakingMain {
                     verifierDestination
                 )
             );
-            require(success, "Delegatecall: legacySlash failed");
+            require(success, HorizonStakingLegacySlashFailed());
             return;
         }
 
@@ -562,6 +562,15 @@ contract HorizonStaking is HorizonStakingBase, IHorizonStakingMain {
         return _isAuthorized(serviceProvider, verifier, operator);
     }
 
+    /*
+     * GETTERS
+     */
+
+    /// @inheritdoc IHorizonStakingMain
+    function getStakingExtension() external view override returns (address) {
+        return STAKING_EXTENSION_ADDRESS;
+    }
+
     /*
      * PRIVATE FUNCTIONS
      */

packages/horizon/contracts/staking/HorizonStakingBase.sol

@@ -50,14 +50,6 @@ abstract contract HorizonStakingBase is
         SUBGRAPH_DATA_SERVICE_ADDRESS = subgraphDataServiceAddress;
     }
 
-    /**
-     * @notice Receive ETH into the Staking contract: this will always revert
-     * @dev This function is only here to prevent ETH from being sent to the contract
-     */
-    receive() external payable {
-        revert("RECEIVE_ETH_NOT_ALLOWED");
-    }
-
     /// @inheritdoc IHorizonStakingBase
     /// @dev Removes deprecated fields from the return value.
     function getServiceProvider(address serviceProvider) external view override returns (ServiceProvider memory) {

packages/horizon/test/staking/delegation/legacyWithdraw.t.sol

@@ -95,7 +95,8 @@ contract HorizonStakingLegacyWithdrawDelegationTest is HorizonStakingTest {
         _setStorage_DelegationPool(users.indexer, 0, 0, 0);
         _setLegacyDelegation(users.indexer, users.delegator, 0, 0, 0);
 
-        vm.expectRevert("!tokens");
+        bytes memory expectedError = abi.encodeWithSignature("HorizonStakingNothingToWithdraw()");
+        vm.expectRevert(expectedError);
         staking.withdrawDelegated(users.indexer, address(0));
     }
 }

packages/horizon/test/staking/slash/legacySlash.t.sol

@@ -204,4 +204,31 @@ contract HorizonStakingLegacySlashTest is HorizonStakingTest {
         resetPrank(users.legacySlasher);
         _legacySlash(users.indexer, 1000 ether, 500 ether, makeAddr("fisherman"));
     }
+
+    function test_LegacySlash_WhenDelegateCallFails() public useIndexer useLegacySlasher(users.legacySlasher) {
+        // Setup indexer with:
+        // - tokensStaked = 1000 GRT
+        // - tokensAllocated = 800 GRT
+        // - tokensLocked = 300 GRT
+
+        _setIndexer(
+            users.indexer,
+            1000 ether, // tokensStaked
+            800 ether, // tokensAllocated
+            300 ether, // tokensLocked
+            0 // tokensLockedUntil
+        );
+
+        // Send tokens manually to staking
+        token.transfer(address(staking), 1100 ether);
+
+        // Change staking extension code to an invalid opcode so the delegatecall reverts
+        address stakingExtension = staking.getStakingExtension();
+        vm.etch(stakingExtension, hex"fe");
+
+        resetPrank(users.legacySlasher);
+        bytes memory expectedError = abi.encodeWithSignature("HorizonStakingLegacySlashFailed()");
+        vm.expectRevert(expectedError);
+        staking.slash(users.indexer, 1000 ether, 500 ether, makeAddr("fisherman"));
+    }
 }