From d75e4f4c75d4a6a62afda1dd7864a8f0c1c14c49 Mon Sep 17 00:00:00 2001
From: lgalende <lau@mimic.fi>
Date: Thu, 2 Jul 2026 00:29:55 -0300
Subject: [PATCH] evm: fix smart accounts handler

---
 .../smart-accounts/SmartAccountsHandler.sol      | 16 ++++++----------
 .../test/smart-accounts/FallbackMock.sol         |  9 +++++++++
 .../smart-accounts/SmartAccountsHandler.test.ts  |  6 ++++++
 3 files changed, 21 insertions(+), 10 deletions(-)
 create mode 100644 packages/evm/contracts/test/smart-accounts/FallbackMock.sol

diff --git a/packages/evm/contracts/smart-accounts/SmartAccountsHandler.sol b/packages/evm/contracts/smart-accounts/SmartAccountsHandler.sol
index b482da3..fb67d62 100644
--- a/packages/evm/contracts/smart-accounts/SmartAccountsHandler.sol
+++ b/packages/evm/contracts/smart-accounts/SmartAccountsHandler.sol
@@ -16,6 +16,7 @@ pragma solidity ^0.8.20;
 
 import '@openzeppelin/contracts/token/ERC20/IERC20.sol';
 import '@openzeppelin/contracts/utils/Address.sol';
+import '@openzeppelin/contracts/utils/introspection/ERC165Checker.sol';
 
 import '../interfaces/ISafe.sol';
 import '../interfaces/ISmartAccount.sol';
@@ -23,6 +24,8 @@ import '../interfaces/ISmartAccountsHandler.sol';
 import '../utils/Denominations.sol';
 
 contract SmartAccountsHandler is ISmartAccountsHandler {
+    using ERC165Checker for address;
+
     /**
      * @dev Tells whether an account is a supported smart account
      * @param account Address of the account being queried
@@ -90,11 +93,7 @@ contract SmartAccountsHandler is ISmartAccountsHandler {
      * @param account Address of the account being queried
      */
     function _isMimicSmartAccount(address account) internal view returns (bool) {
-        try ISmartAccount(account).supportsInterface(type(ISmartAccount).interfaceId) returns (bool ok) {
-            return ok;
-        } catch {
-            return false;
-        }
+        return account.supportsInterface(type(ISmartAccount).interfaceId);
     }
 
     /**
@@ -102,10 +101,7 @@ contract SmartAccountsHandler is ISmartAccountsHandler {
      * @param account Address of the account being queried
      */
     function _isSafe(address account) internal view returns (bool) {
-        try ISafe(account).getThreshold() returns (uint256) {
-            return true;
-        } catch {
-            return false;
-        }
+        (bool success, bytes memory data) = account.staticcall(abi.encodeWithSelector(ISafe.getThreshold.selector));
+        return success && data.length == 32;
     }
 }
diff --git a/packages/evm/contracts/test/smart-accounts/FallbackMock.sol b/packages/evm/contracts/test/smart-accounts/FallbackMock.sol
new file mode 100644
index 0000000..1b998b4
--- /dev/null
+++ b/packages/evm/contracts/test/smart-accounts/FallbackMock.sol
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+contract FallbackMock {
+    fallback() external payable {}
+
+    receive() external payable {}
+}
diff --git a/packages/evm/test/smart-accounts/SmartAccountsHandler.test.ts b/packages/evm/test/smart-accounts/SmartAccountsHandler.test.ts
index 382be61..31fb7ec 100644
--- a/packages/evm/test/smart-accounts/SmartAccountsHandler.test.ts
+++ b/packages/evm/test/smart-accounts/SmartAccountsHandler.test.ts
@@ -45,6 +45,12 @@ describe('SmartAccountsHandler', () => {
       expect(await handler.isSmartAccount(handler)).to.be.false
     })
 
+    it('returns false for contracts with a fallback only', async () => {
+      const fallback = await ethers.deployContract('FallbackMock')
+
+      expect(await handler.isSmartAccount(fallback)).to.be.false
+    })
+
     it('returns true for a Mimic SmartAccount', async () => {
       expect(await handler.isSmartAccount(smartAccountContract)).to.be.true
     })