feat: LensModule interface with ERC165 standard and metadata [P-21] T-16815

Co-authored-by: Alan <donosonaumczuk@gmail.com>

contracts/misc/ModuleRegistry.sol

@@ -4,6 +4,11 @@ pragma solidity ^0.8.15;
 
 import {IModuleRegistry} from 'contracts/interfaces/IModuleRegistry.sol';
 import {IERC20Metadata} from '@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol';
+import {ILensModule} from 'contracts/modules/interfaces/ILensModule.sol';
+
+import {IPublicationActionModule} from 'contracts/interfaces/IPublicationActionModule.sol';
+import {IFollowModule} from 'contracts/interfaces/IFollowModule.sol';
+import {IReferenceModule} from 'contracts/interfaces/IReferenceModule.sol';
 
 /**
  * @title ModuleRegistry
@@ -12,7 +17,14 @@ import {IERC20Metadata} from '@openzeppelin/contracts/token/ERC20/extensions/IER
  * @custom:upgradeable Transparent upgradeable proxy without initializer.
  */
 contract ModuleRegistry is IModuleRegistry {
-    event ModuleRegistered(address indexed moduleAddress, uint256 indexed moduleType, uint256 timestamp);
+    bytes4 private constant LENS_MODULE_INTERFACE_ID = bytes4(keccak256(abi.encodePacked('LENS_MODULE')));
+
+    event ModuleRegistered(
+        address indexed moduleAddress,
+        uint256 indexed moduleType,
+        string metadata,
+        uint256 timestamp
+    );
 
     event erc20CurrencyRegistered(
         address indexed erc20CurrencyAddress,
@@ -22,6 +34,9 @@ contract ModuleRegistry is IModuleRegistry {
         uint256 timestamp
     );
 
+    error NotLensModule();
+    error ModuleDoesNotSupportType(uint256 moduleType);
+
     mapping(address moduleAddress => uint256 moduleTypesBitmap) internal registeredModules;
 
     mapping(address erc20CurrencyAddress => bool) internal registeredErc20Currencies;
@@ -44,12 +59,36 @@ contract ModuleRegistry is IModuleRegistry {
         if (isAlreadyRegisteredAsThatType) {
             return false;
         } else {
-            emit ModuleRegistered(moduleAddress, moduleType, block.timestamp);
+            if (!ILensModule(moduleAddress).supportsInterface(LENS_MODULE_INTERFACE_ID)) {
+                revert NotLensModule();
+            }
+
+            validateModuleSupportsType(moduleAddress, moduleType);
+
+            string memory metadata = ILensModule(moduleAddress).getModuleMetadataURI();
+            emit ModuleRegistered(moduleAddress, moduleType, metadata, block.timestamp);
             registeredModules[moduleAddress] |= (1 << moduleType);
             return true;
         }
     }
 
+    function validateModuleSupportsType(address moduleAddress, uint256 moduleType) internal view {
+        bool supportsInterface;
+        if (moduleType == uint256(IModuleRegistry.ModuleType.PUBLICATION_ACTION_MODULE)) {
+            supportsInterface = ILensModule(moduleAddress).supportsInterface(
+                type(IPublicationActionModule).interfaceId
+            );
+        } else if (moduleType == uint256(IModuleRegistry.ModuleType.FOLLOW_MODULE)) {
+            supportsInterface = ILensModule(moduleAddress).supportsInterface(type(IFollowModule).interfaceId);
+        } else if (moduleType == uint256(IModuleRegistry.ModuleType.REFERENCE_MODULE)) {
+            supportsInterface = ILensModule(moduleAddress).supportsInterface(type(IReferenceModule).interfaceId);
+        }
+
+        if (!supportsInterface) {
+            revert ModuleDoesNotSupportType(moduleType);
+        }
+    }
+
     function getModuleTypes(address moduleAddress) public view returns (uint256) {
         return registeredModules[moduleAddress];
     }

contracts/modules/LensModule.sol

@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.18;
+
+import {ILensModule} from 'contracts/modules/interfaces/ILensModule.sol';
+
+abstract contract LensModule is ILensModule {
+    /// @inheritdoc ILensModule
+    function supportsInterface(bytes4 interfaceID) public pure virtual override returns (bool) {
+        return interfaceID == bytes4(keccak256(abi.encodePacked('LENS_MODULE')));
+    }
+}

contracts/modules/act/collect/CollectPublicationAction.sol

@@ -10,7 +10,19 @@ import {Clones} from '@openzeppelin/contracts/proxy/Clones.sol';
 import {Errors} from 'contracts/modules/constants/Errors.sol';
 import {HubRestricted} from 'contracts/base/HubRestricted.sol';
 
-contract CollectPublicationAction is HubRestricted, IPublicationActionModule {
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
+/**
+ * @title CollectPublicationAction
+ * @author LensProtocol
+ * @notice An Publication Action module that allows users to collect publications.
+ * @custom:upgradeable Transparent upgradeable proxy without initializer.
+ */
+contract CollectPublicationAction is LensModule, HubRestricted, IPublicationActionModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IPublicationActionModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     struct CollectData {
         address collectModule;
         address collectNFT;
@@ -204,4 +216,8 @@ contract CollectPublicationAction is HubRestricted, IPublicationActionModule {
     function isCollectModuleRegistered(address collectModule) external view returns (bool) {
         return _collectModuleRegistered[collectModule];
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/act/seadrop/SeaDropMintPublicationAction.sol

@@ -17,7 +17,13 @@ import {PublicDrop} from '@seadrop/lib/SeaDropStructs.sol';
 import {LensSeaDropCollection} from 'contracts/modules/act/seadrop/LensSeaDropCollection.sol';
 import {ILensHub} from 'contracts/interfaces/ILensHub.sol';
 
-contract SeaDropMintPublicationAction is HubRestricted, IPublicationActionModule {
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
+contract SeaDropMintPublicationAction is LensModule, HubRestricted, IPublicationActionModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IPublicationActionModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     uint256 constant MAX_BPS = 10_000;
 
     ISeaDrop public immutable SEADROP;
@@ -274,4 +280,8 @@ contract SeaDropMintPublicationAction is HubRestricted, IPublicationActionModule
             _rescaleFees(profileId, pubId, lensTreasuryFeeBps, publicDrop);
         }
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/follow/FeeFollowModule.sol

@@ -9,6 +9,8 @@ import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
 import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
 import {HubRestricted} from 'contracts/base/HubRestricted.sol';
 
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
 /**
  * @notice A struct containing the necessary data to execute follow actions on a given profile.
  *
@@ -28,7 +30,11 @@ struct FeeConfig {
  *
  * @notice This follow module charges a fee for every follow.
  */
-contract FeeFollowModule is FeeModuleBase, HubRestricted, IFollowModule {
+contract FeeFollowModule is LensModule, FeeModuleBase, HubRestricted, IFollowModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IFollowModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     using SafeERC20 for IERC20;
 
     mapping(uint256 profileId => FeeConfig config) internal _feeConfig;
@@ -116,4 +122,8 @@ contract FeeFollowModule is FeeModuleBase, HubRestricted, IFollowModule {
     function getFeeConfig(uint256 profileId) external view returns (FeeConfig memory) {
         return _feeConfig[profileId];
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/follow/RevertFollowModule.sol

@@ -5,17 +5,23 @@ pragma solidity ^0.8.10;
 import {Errors} from 'contracts/modules/constants/Errors.sol';
 import {IFollowModule} from 'contracts/interfaces/IFollowModule.sol';
 
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
 /**
  * @title RevertFollowModule
  * @author Lens Protocol
  *
  * @notice This follow module rejects all follow attempts.
  */
-contract RevertFollowModule is IFollowModule {
+contract RevertFollowModule is LensModule, IFollowModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IFollowModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     /// @inheritdoc IFollowModule
     function initializeFollowModule(
-        uint256, /* profileId */
-        address, /* transactionExecutor */
+        uint256 /* profileId */,
+        address /* transactionExecutor */,
         bytes calldata /* data */
     ) external pure override returns (bytes memory) {
         return '';
@@ -26,12 +32,16 @@ contract RevertFollowModule is IFollowModule {
      * @notice Processes a follow by rejecting it, reverting the transaction. Parameters are ignored.
      */
     function processFollow(
-        uint256, /* followerProfileId */
-        uint256, /* followTokenId */
-        address, /* transactionExecutor */
-        uint256, /* profileId */
+        uint256 /* followerProfileId */,
+        uint256 /* followTokenId */,
+        address /* transactionExecutor */,
+        uint256 /* profileId */,
         bytes calldata /* data */
     ) external pure override returns (bytes memory) {
         revert Errors.FollowInvalid();
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/interfaces/ILensModule.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.6.0;
+
+import {IERC165} from '@openzeppelin/contracts/utils/introspection/IERC165.sol';
+
+interface ILensModule is IERC165 {
+    /// @dev for now we check for keccak('LENS_MODULE');
+    /// Override this and add the type(IModuleInterface).interfaceId for corresponding module type
+    function supportsInterface(bytes4 interfaceID) external view returns (bool);
+
+    /// @notice Human-readable description of the module
+    // Can be JSON
+    // Can be contract source code
+    // Can be github link
+    // Can be ipfs with documentation
+    // etc
+    function getModuleMetadataURI() external view returns (string memory);
+}

contracts/modules/reference/DegreesOfSeparationReferenceModule.sol

@@ -10,6 +10,8 @@ import {IReferenceModule} from 'contracts/interfaces/IReferenceModule.sol';
 import {HubRestricted} from 'contracts/base/HubRestricted.sol';
 import {FollowValidationLib} from 'contracts/modules/libraries/FollowValidationLib.sol';
 
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
 /**
  * @notice Struct representing the module configuration for certain publication.
  *
@@ -40,7 +42,11 @@ struct ModuleConfig {
  * only to profiles that are at most at `n` degrees of separation from the source profile, which is expected to be set
  * as the author of the root publication.
  */
-contract DegreesOfSeparationReferenceModule is HubRestricted, IReferenceModule {
+contract DegreesOfSeparationReferenceModule is LensModule, HubRestricted, IReferenceModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IReferenceModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     error InvalidDegreesOfSeparation();
     error OperationDisabled();
     error ProfilePathExceedsDegreesOfSeparation();
@@ -301,4 +307,8 @@ contract DegreesOfSeparationReferenceModule is HubRestricted, IReferenceModule {
             revert NotInheritingPointedPubConfig();
         }
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/reference/FollowerOnlyReferenceModule.sol

@@ -7,6 +7,8 @@ import {HubRestricted} from 'contracts/base/HubRestricted.sol';
 import {Types} from 'contracts/libraries/constants/Types.sol';
 import {FollowValidationLib} from 'contracts/modules/libraries/FollowValidationLib.sol';
 
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
 /**
  * @title FollowerOnlyReferenceModule
  * @author Lens Protocol
@@ -14,7 +16,11 @@ import {FollowValidationLib} from 'contracts/modules/libraries/FollowValidationL
  * @notice A simple reference module that validates that comments, quotes or mirrors originate from a profile that
  * follows the profile of the original publication.
  */
-contract FollowerOnlyReferenceModule is HubRestricted, IReferenceModule {
+contract FollowerOnlyReferenceModule is LensModule, HubRestricted, IReferenceModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IReferenceModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     constructor(address hub) HubRestricted(hub) {}
 
     /**
@@ -85,4 +91,8 @@ contract FollowerOnlyReferenceModule is HubRestricted, IReferenceModule {
         }
         return '';
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

contracts/modules/reference/TokenGatedReferenceModule.sol

@@ -8,6 +8,8 @@ import {Errors} from 'contracts/modules/constants/Errors.sol';
 import {IERC721} from '@openzeppelin/contracts/token/ERC721/IERC721.sol';
 import {Types} from 'contracts/libraries/constants/Types.sol';
 
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
 interface IToken {
     /**
      * @dev Returns the amount of ERC20/ERC721 tokens owned by `account`.
@@ -32,7 +34,11 @@ struct GateParams {
  *
  * @notice A reference module that validates that the user who tries to reference has a required minimum balance of ERC20/ERC721 token.
  */
-contract TokenGatedReferenceModule is HubRestricted, IReferenceModule {
+contract TokenGatedReferenceModule is LensModule, HubRestricted, IReferenceModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IReferenceModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     uint256 internal constant UINT256_BYTES = 32;
 
     event TokenGatedReferencePublicationCreated(
@@ -154,4 +160,8 @@ contract TokenGatedReferenceModule is HubRestricted, IReferenceModule {
         }
         return balance;
     }
+
+    function getModuleMetadataURI() external pure returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

test/mocks/MockActionModule.sol

@@ -10,6 +10,10 @@ import {MockModule} from 'test/mocks/MockModule.sol';
  * @dev This is a simple mock Action module to be used for testing revert cases on processAction.
  */
 contract MockActionModule is MockModule, IPublicationActionModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IPublicationActionModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     error MockActionModuleReverted();
 
     function testMockActionModule() public {

test/mocks/MockFollowModule.sol

@@ -3,11 +3,16 @@
 pragma solidity ^0.8.15;
 
 import {IFollowModule} from 'contracts/interfaces/IFollowModule.sol';
+import {LensModule} from 'contracts/modules/LensModule.sol';
 
 /**
  * @dev This is a simple mock follow module to be used for testing.
  */
-contract MockFollowModule is IFollowModule {
+contract MockFollowModule is LensModule, IFollowModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IFollowModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     function testMockFollowModule() public {
         // Prevents being counted in Foundry Coverage
     }
@@ -29,4 +34,8 @@ contract MockFollowModule is IFollowModule {
         uint256 profileId,
         bytes calldata data
     ) external pure override returns (bytes memory) {}
+
+    function getModuleMetadataURI() external pure override returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

test/mocks/MockFollowModuleWithRevertFlag.sol

@@ -3,11 +3,16 @@
 pragma solidity ^0.8.15;
 
 import {IFollowModule} from 'contracts/interfaces/IFollowModule.sol';
+import {LensModule} from 'contracts/modules/LensModule.sol';
 
 /**
  * @dev This is a simple mock follow module to be used for testing revert cases on processFollow.
  */
-contract MockFollowModuleWithRevertFlag is IFollowModule {
+contract MockFollowModuleWithRevertFlag is LensModule, IFollowModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IFollowModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     error MockFollowModuleReverted();
 
     function testMockFollowModuleWithRevertFlag() public {
@@ -34,4 +39,8 @@ contract MockFollowModuleWithRevertFlag is IFollowModule {
         }
         return '';
     }
+
+    function getModuleMetadataURI() external pure override returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

test/mocks/MockModule.sol

@@ -2,7 +2,9 @@
 
 pragma solidity ^0.8.15;
 
-abstract contract MockModule {
+import {LensModule} from 'contracts/modules/LensModule.sol';
+
+abstract contract MockModule is LensModule {
     error MockModuleReverted();
 
     function testMockModule() public {
@@ -17,4 +19,8 @@ abstract contract MockModule {
         }
         return data;
     }
+
+    function getModuleMetadataURI() external pure override returns (string memory) {
+        return 'https://docs.lens.xyz/';
+    }
 }

test/mocks/MockReferenceModule.sol

@@ -10,6 +10,10 @@ import {MockModule} from 'test/mocks/MockModule.sol';
  * @dev This is a simple mock follow module to be used for testing.
  */
 contract MockReferenceModule is MockModule, IReferenceModule {
+    function supportsInterface(bytes4 interfaceID) public pure override returns (bool) {
+        return interfaceID == type(IReferenceModule).interfaceId || super.supportsInterface(interfaceID);
+    }
+
     function testMockReferenceModule() public {
         // Prevents being counted in Foundry Coverage
     }