From ff2a495389589549905eca37f0c7bf0c87e80295 Mon Sep 17 00:00:00 2001
From: Yorke Rhodes <yorke@hyperlane.xyz>
Date: Fri, 18 Aug 2023 16:13:42 -0400
Subject: [PATCH] Add pausable ism (#2675)

---
 solidity/contracts/isms/PausableIsm.sol | 34 +++++++++++++++++++++++++
 solidity/test/isms/PausableIsm.t.sol    | 32 +++++++++++++++++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 solidity/contracts/isms/PausableIsm.sol
 create mode 100644 solidity/test/isms/PausableIsm.t.sol

diff --git a/solidity/contracts/isms/PausableIsm.sol b/solidity/contracts/isms/PausableIsm.sol
new file mode 100644
index 000000000..54c054104
--- /dev/null
+++ b/solidity/contracts/isms/PausableIsm.sol
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+pragma solidity >=0.8.0;
+
+// ============ External Imports ============
+import {Pausable} from "@openzeppelin/contracts/security/Pausable.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
+
+// ============ Internal Imports ============
+import {IInterchainSecurityModule} from "../interfaces/IInterchainSecurityModule.sol";
+
+contract PausableIsm is IInterchainSecurityModule, Ownable, Pausable {
+    uint8 public constant override moduleType = uint8(Types.NULL);
+
+    /**
+     * @inheritdoc IInterchainSecurityModule
+     * @dev Reverts when paused, otherwise returns `true`.
+     */
+    function verify(bytes calldata, bytes calldata)
+        external
+        view
+        whenNotPaused
+        returns (bool)
+    {
+        return true;
+    }
+
+    function pause() external onlyOwner {
+        _pause();
+    }
+
+    function unpause() external onlyOwner {
+        _unpause();
+    }
+}
diff --git a/solidity/test/isms/PausableIsm.t.sol b/solidity/test/isms/PausableIsm.t.sol
new file mode 100644
index 000000000..74a2bfdd7
--- /dev/null
+++ b/solidity/test/isms/PausableIsm.t.sol
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: MIT or Apache-2.0
+pragma solidity ^0.8.13;
+
+import {Test} from "forge-std/Test.sol";
+
+import {PausableIsm} from "../../contracts/isms/PausableIsm.sol";
+
+contract PausableIsmTest is Test {
+    PausableIsm ism;
+
+    function setUp() public {
+        ism = new PausableIsm();
+    }
+
+    function test_verify() public {
+        assertTrue(ism.verify("", ""));
+        ism.pause();
+        vm.expectRevert(bytes("Pausable: paused"));
+        ism.verify("", "");
+    }
+
+    function test_pause() public {
+        ism.pause();
+        assertTrue(ism.paused());
+    }
+
+    function test_unpause() public {
+        ism.pause();
+        ism.unpause();
+        assertFalse(ism.paused());
+    }
+}