add ICreatorToken

src-upgradeable/src/ERC721ContractMetadataUpgradeable.sol

@@ -13,7 +13,13 @@ import {
     ERC721TransferValidatorUpgradeable
 } from "./lib/ERC721TransferValidatorUpgradeable.sol";
 
-import { ERC721AUpgradeable } from "../lib/ERC721A-Upgradeable/contracts/ERC721AUpgradeable.sol";
+import { ICreatorToken } from "./interfaces/ICreatorToken.sol";
+
+import { ITransferValidator } from "./interfaces/ITransferValidator.sol";
+
+import {
+    ERC721AUpgradeable
+} from "../lib/ERC721A-Upgradeable/contracts/ERC721AUpgradeable.sol";
 
 import {
     TwoStepOwnableUpgradeable
@@ -332,6 +338,7 @@ contract ERC721ContractMetadataUpgradeable is
     {
         return
             interfaceId == type(IERC2981Upgradeable).interfaceId ||
+            interfaceId == type(ICreatorToken).interfaceId ||
             interfaceId == 0x49064906 || // ERC-4906
             super.supportsInterface(interfaceId);
     }

src-upgradeable/src/interfaces/ICreatorToken.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.17;
+
+interface ICreatorToken {
+    event TransferValidatorUpdated(address oldValidator, address newValidator);
+
+    function getTransferValidator() external view returns (address validator);
+
+    function setTransferValidator(address validator) external;
+}

src/ERC721ContractMetadata.sol

@@ -11,6 +11,8 @@ import { ERC721AConduitPreapproved } from "./lib/ERC721AConduitPreapproved.sol";
 
 import { ERC721TransferValidator } from "./lib/ERC721TransferValidator.sol";
 
+import { ICreatorToken } from "./interfaces/ICreatorToken.sol";
+
 import { ITransferValidator } from "./interfaces/ITransferValidator.sol";
 
 import { TwoStepOwnable } from "utility-contracts/TwoStepOwnable.sol";
@@ -326,6 +328,7 @@ contract ERC721ContractMetadata is
     {
         return
             interfaceId == type(IERC2981).interfaceId ||
+            interfaceId == type(ICreatorToken).interfaceId ||
             interfaceId == 0x49064906 || // ERC-4906
             super.supportsInterface(interfaceId);
     }

src/clones/ERC721ContractMetadataCloneable.sol

@@ -13,6 +13,8 @@ import { ERC721ACloneable } from "./ERC721ACloneable.sol";
 
 import { ERC721TransferValidator } from "../lib/ERC721TransferValidator.sol";
 
+import { ICreatorToken } from "../interfaces/ICreatorToken.sol";
+
 import { ITransferValidator } from "../interfaces/ITransferValidator.sol";
 
 import { TwoStepOwnable } from "utility-contracts/TwoStepOwnable.sol";
@@ -321,6 +323,7 @@ contract ERC721ContractMetadataCloneable is
     {
         return
             interfaceId == type(IERC2981).interfaceId ||
+            interfaceId == type(ICreatorToken).interfaceId ||
             interfaceId == 0x49064906 || // ERC-4906
             super.supportsInterface(interfaceId);
     }

src/interfaces/ICreatorToken.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.17;
+
+interface ICreatorToken {
+    event TransferValidatorUpdated(address oldValidator, address newValidator);
+
+    function getTransferValidator() external view returns (address validator);
+
+    function setTransferValidator(address validator) external;
+}

src/lib/ERC721TransferValidator.sol

@@ -1,17 +1,16 @@
 // SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
+import { ICreatorToken } from "../interfaces/ICreatorToken.sol";
+
 /**
  * @title  ERC721TransferValidator
  * @notice Functionality to use a transfer validator.
  */
-contract ERC721TransferValidator {
+abstract contract ERC721TransferValidator is ICreatorToken {
     /// @dev Store the transfer validator. The null address means no transfer validator is set.
     address internal _transferValidator;
 
-    /// @notice Emit an event when the transfer validator is updated.
-    event TransferValidatorUpdated(address oldValidator, address newValidator);
-
     /// @notice Revert with an error if the transfer validator is being set to the same address.
     error SameTransferValidator();
 

test/ERC721SeaDrop.spec.ts

@@ -2,6 +2,7 @@ import { expect } from "chai";
 import { ethers, network } from "hardhat";
 
 import {
+  ICreatorToken__factory,
   IERC165__factory,
   IERC2981__factory,
   IERC721__factory,
@@ -266,6 +267,7 @@ describe(`ERC721SeaDrop (v${VERSION})`, function () {
     const supportedInterfacesERC721ContractMetadata = [
       [ISeaDropTokenContractMetadata__factory, IERC2981__factory],
       [IERC2981__factory, IERC165__factory],
+      [ICreatorToken__factory],
     ];
     const supportedInterfacesERC721A = [
       [IERC721__factory, IERC165__factory],