[IP-527] Bring your own IPT: Tokenizer allows attaching arbitrary ERC20s

src/Tokenizer.sol

@@ -37,6 +37,7 @@ contract Tokenizer is UUPSUpgradeable, OwnableUpgradeable, IControlIPTs {
         string symbol
     );
 
+    // @dev @TODO: index these topics
     event TokenWrapped(IERC20Metadata tokenContract, IIPToken wrappedIpt);
     event IPTokenImplementationUpdated(IIPToken indexed old, IIPToken indexed _new);
     event WrappedIPTokenImplementationUpdated(WrappedIPToken indexed old, WrappedIPToken indexed _new);

src/WrappedIPToken.sol

@@ -9,8 +9,11 @@ import { IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/I
 /**
  * @title WrappedIPToken
  * @author molecule.xyz
- * @notice this is a template contract that's cloned by the Tokenizer
- * @notice this contract is used to wrap an ERC20 token and extend its metadata
+ * @notice A read-only wrapper that extends existing ERC20 tokens with IP metadata
+ * @dev This contract provides IP metadata for an existing ERC20 token without proxying
+ *      state-changing operations. It only implements IIPToken interface functions and
+ *      read-only ERC20 view functions. Users must interact with the underlying token
+ *      directly for transfers, approvals, and other state changes.
  */
 contract WrappedIPToken is IIPToken, Initializable {
     IERC20Metadata public wrappedToken;
@@ -62,32 +65,16 @@ contract WrappedIPToken is IIPToken, Initializable {
         return wrappedToken.balanceOf(account);
     }
 
-    function transfer(address to, uint256 amount) public returns (bool) {
-        return wrappedToken.transfer(to, amount);
-    }
-
-    function allowance(address owner, address spender) public view returns (uint256) {
-        return wrappedToken.allowance(owner, spender);
-    }
-
-    function approve(address spender, uint256 amount) public returns (bool) {
-        return wrappedToken.approve(spender, amount);
-    }
-
-    function transferFrom(address from, address to, uint256 amount) public returns (bool) {
-        return wrappedToken.transferFrom(from, to, amount);
-    }
-
     function totalIssued() public view override returns (uint256) {
         return wrappedToken.totalSupply();
     }
 
     function issue(address, uint256) public virtual override {
-        revert("WrappedIPToken: cannot issue");
+        revert("WrappedIPToken: read-only wrapper - use underlying token for minting");
     }
 
     function cap() public virtual override {
-        revert("WrappedIPToken: cannot cap");
+        revert("WrappedIPToken: read-only wrapper - use underlying token for cappping");
     }
 
     function uri() external view override returns (string memory) {

test/Forking/Tokenizer14UpgradeForkTest.t.sol

@@ -414,6 +414,9 @@ contract Tokenizer14UpgradeForkTest is Test {
         vm.expectRevert(); // WrappedIPToken should not allow cap operations
         WrappedIPToken(address(wrappedToken)).cap();
 
+        // Test that WrappedIPToken only implements IIPToken state-changing operations (which revert)
+        // ERC20 state-changing functions are no longer implemented
+
         // Test that we cannot attach another token to the same IPNFT
         FakeERC20 anotherToken = new FakeERC20("Another Token", "ANT");
         vm.expectRevert(AlreadyTokenized.selector);

test/TokenizerWrapped.t.sol

@@ -144,13 +144,77 @@ contract TokenizerWrappedTest is Test {
         IIPToken tokenContract = tokenizer.attachIpt(1, agreementCid, "", erc20);
 
         // Wrapped tokens should not be able to issue or cap
-        vm.expectRevert("WrappedIPToken: cannot issue");
+        vm.expectRevert("WrappedIPToken: read-only wrapper - use underlying token for minting");
         tokenContract.issue(alice, 1000);
 
-        vm.expectRevert("WrappedIPToken: cannot cap");
+        vm.expectRevert("WrappedIPToken: read-only wrapper - use underlying token for cappping");
         tokenContract.cap();
     }
 
+    function testWrappedTokenStateChangingOperationsRevert() public {
+        vm.startPrank(originalOwner);
+        erc20 = new FakeERC20("TestToken", "TEST");
+        erc20.mint(originalOwner, 1_000_000 ether);
+
+        IIPToken tokenContract = tokenizer.attachIpt(1, agreementCid, "", erc20);
+
+        // Test that IIPToken state-changing operations revert with proper messages
+        vm.expectRevert("WrappedIPToken: read-only wrapper - use underlying token for minting");
+        tokenContract.issue(alice, 1000);
+
+        vm.expectRevert("WrappedIPToken: read-only wrapper - use underlying token for cappping");
+        tokenContract.cap();
+    }
+
+    function testWrappedTokenReadOnlyOperationsWork() public {
+        vm.startPrank(originalOwner);
+        erc20 = new FakeERC20("TestToken", "TEST");
+        erc20.mint(originalOwner, 1_000_000 ether);
+
+        IIPToken tokenContract = tokenizer.attachIpt(1, agreementCid, "", erc20);
+        WrappedIPToken wrappedToken = WrappedIPToken(address(tokenContract));
+
+        // Test that read-only operations still work
+        assertEq(wrappedToken.balanceOf(originalOwner), 1_000_000 ether);
+        assertEq(wrappedToken.totalSupply(), 1_000_000 ether);
+        assertEq(wrappedToken.name(), "TestToken");
+        assertEq(wrappedToken.symbol(), "TEST");
+        assertEq(wrappedToken.decimals(), 18);
+        assertEq(wrappedToken.totalIssued(), 1_000_000 ether);
+
+        // Test IP metadata functions work
+        assertEq(wrappedToken.metadata().ipnftId, 1);
+        assertEq(wrappedToken.metadata().originalOwner, originalOwner);
+        assertEq(wrappedToken.metadata().agreementCid, agreementCid);
+
+        // Test URI function works
+        string memory uri = wrappedToken.uri();
+        assertTrue(bytes(uri).length > 0);
+    }
+
+    function testUnderlyingTokenOperationsStillWork() public {
+        vm.startPrank(originalOwner);
+        erc20 = new FakeERC20("TestToken", "TEST");
+        erc20.mint(originalOwner, 1_000_000 ether);
+
+        IIPToken tokenContract = tokenizer.attachIpt(1, agreementCid, "", erc20);
+
+        // Users can still use the underlying token directly for transfers
+        assertTrue(erc20.transfer(alice, 100_000 ether));
+        assertEq(erc20.balanceOf(alice), 100_000 ether);
+        assertEq(erc20.balanceOf(originalOwner), 900_000 ether);
+
+        // Approvals work on the underlying token
+        assertTrue(erc20.approve(alice, 50_000 ether));
+        assertEq(erc20.allowance(originalOwner, alice), 50_000 ether);
+
+        // Transfer from works on the underlying token
+        vm.startPrank(alice);
+        assertTrue(erc20.transferFrom(originalOwner, alice, 25_000 ether));
+        assertEq(erc20.balanceOf(alice), 125_000 ether);
+        assertEq(erc20.balanceOf(originalOwner), 875_000 ether);
+    }
+
     // Helper function to check if a string contains a substring
     function contains(string memory source, string memory search) internal pure returns (bool) {
         bytes memory sourceBytes = bytes(source);