[3/n] Enable validation composability and add composable single singer validation and tests

README.md

@@ -2,7 +2,7 @@
 
 Reference implementation for [ERC-6900](https://eips.ethereum.org/EIPS/eip-6900). It is an early draft implementation.
 
-The implementation includes an upgradable modular account with two plugins (`SingleOwnerPlugin` and `TokenReceiverPlugin`). It is compliant with ERC-6900 with the latest updates.
+The implementation includes an upgradable modular account with two plugins (`SingleSignerValidation` and `TokenReceiverPlugin`). It is compliant with ERC-6900 with the latest updates.
 
 ## Important Callouts
 

src/account/UpgradeableModularAccount.sol

@@ -348,8 +348,10 @@ contract UpgradeableModularAccount is
             revert SignatureValidationInvalid(plugin, entityId);
         }
 
-        if (IValidation(plugin).validateSignature(entityId, msg.sender, hash, signature[24:]) == _1271_MAGIC_VALUE)
-        {
+        if (
+            IValidation(plugin).validateSignature(address(this), entityId, msg.sender, hash, signature[24:])
+                == _1271_MAGIC_VALUE
+        ) {
             return _1271_MAGIC_VALUE;
         }
         return _1271_INVALID;
@@ -517,7 +519,9 @@ contract UpgradeableModularAccount is
 
         (address plugin, uint32 entityId) = runtimeValidationFunction.unpack();
 
-        try IValidation(plugin).validateRuntime(entityId, msg.sender, msg.value, callData, authSegment.getBody())
+        try IValidation(plugin).validateRuntime(
+            address(this), entityId, msg.sender, msg.value, callData, authSegment.getBody()
+        )
         // forgefmt: disable-start
         // solhint-disable-next-line no-empty-blocks
         {} catch (bytes memory revertReason) {

src/interfaces/IValidation.sol

@@ -18,13 +18,15 @@ interface IValidation is IPlugin {
 
     /// @notice Run the runtime validationFunction specified by the `entityId`.
     /// @dev To indicate the entire call should revert, the function MUST revert.
+    /// @param account the account to validate for.
     /// @param entityId An identifier that routes the call to different internal implementations, should there
     /// be more than one.
     /// @param sender The caller address.
     /// @param value The call value.
     /// @param data The calldata sent.
     /// @param authorization Additional data for the validation function to use.
     function validateRuntime(
+        address account,
         uint32 entityId,
         address sender,
         uint256 value,
@@ -34,14 +36,18 @@ interface IValidation is IPlugin {
 
     /// @notice Validates a signature using ERC-1271.
     /// @dev To indicate the entire call should revert, the function MUST revert.
+    /// @param account the account to validate for.
     /// @param entityId An identifier that routes the call to different internal implementations, should there
     /// be more than one.
     /// @param sender the address that sent the ERC-1271 request to the smart account
     /// @param hash the hash of the ERC-1271 request
     /// @param signature the signature of the ERC-1271 request
     /// @return the ERC-1271 `MAGIC_VALUE` if the signature is valid, or 0xFFFFFFFF if invalid.
-    function validateSignature(uint32 entityId, address sender, bytes32 hash, bytes calldata signature)
-        external
-        view
-        returns (bytes4);
+    function validateSignature(
+        address account,
+        uint32 entityId,
+        address sender,
+        bytes32 hash,
+        bytes calldata signature
+    ) external view returns (bytes4);
 }

src/plugins/validation/ISingleSignerValidation.sol

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.25;
+
+import {IValidation} from "../../interfaces/IValidation.sol";
+
+interface ISingleSignerValidation is IValidation {
+    /// @notice This event is emitted when Signer of the account's validation changes.
+    /// @param account The account whose validation Signer changed.
+    /// @param entityId The entityId for the account and the signer.
+    /// @param previousSigner The address of the previous signer.
+    /// @param newSigner The address of the new signer.
+    event SignerTransferred(
+        address indexed account, uint32 indexed entityId, address previousSigner, address newSigner
+    );
+
+    error NotAuthorized();
+
+    /// @notice Transfer Signer of the account's validation to `newSigner`.
+    /// @param entityId The entityId for the account and the signer.
+    /// @param newSigner The address of the new signer.
+    function transferSigner(uint32 entityId, address newSigner) external;
+
+    /// @notice Get the signer of the `account`'s validation.
+    /// @param entityId The entityId for the account and the signer.
+    /// @param account The account to get the signer of.
+    /// @return The address of the signer.
+    function signerOf(uint32 entityId, address account) external view returns (address);
+}