0.3.0: add overflow error

README.md

@@ -66,6 +66,8 @@ leads. The leads can choose to update this value themselves.
 
 | Contract | Address | Version |
 | -------- | ------- | ------- |
+| `PactFactory` | [0x0bc342e7bbf737ba123b1167e528a28cebb8b679](https://optimistic.etherscan.io/address/0x0bc342e7bbf737ba123b1167e528a28cebb8b679) | `0.3.0` |
+| `Pact` (implementation) | [0x60d1a1755065e4cac8777248c2878c847c9a5dd5](https://optimistic.etherscan.io/address/0x60d1a1755065e4cac8777248c2878c847c9a5dd5) | `0.3.0` |
 | `PactFactory` | [0x642a7864cBe44ED24D408Cbc38117Cfd6E6D1a95](https://optimistic.etherscan.io/address/0x642a7864cBe44ED24D408Cbc38117Cfd6E6D1a95) | `0.2.0` |
 | `Pact` (implementation) | [0x4eE4ff6D24c8D334fA41b560Dac95BB3CEF828a1](https://optimistic.etherscan.io/address/0x4eE4ff6D24c8D334fA41b560Dac95BB3CEF828a1) | `0.2.0` |
 

src/Pact.sol

@@ -18,7 +18,7 @@ import { SafeCall } from "./SafeCall.sol";
 ///         It is expected that the pre-agreed upon commitment is observed. The rule of law
 ///         dictates meatspace.
 contract Pact is Clone {
-    string constant public version = "0.2.0";
+    string constant public version = "0.3.0";
 
     /// @notice Used to determine if the pact has been initialized.
     bool internal _initialized;
@@ -68,6 +68,9 @@ contract Pact is Clone {
     /// @notice Error when trying to resolve the Pact too early.
     error Early();
 
+    /// @notice Error when putting too much value into the Pact.
+    error Overflow();
+
     /// @notice Error when trying to `initialize()` when the Pact has
     ///         already been initialized.
     error Initialized();
@@ -90,6 +93,7 @@ contract Pact is Clone {
     ///         so that ether can be returned in case not enough capital is accumulated.
     fallback() external payable {
         if (resolved) revert Resolved();
+        if (address(this).balance > sum()) revert Overflow();
 
         address sender = msg.sender;
         uint256 value = msg.value;
@@ -119,7 +123,12 @@ contract Pact is Clone {
         return duration() + start;
     }
 
-    /// @notice
+    /// @notice Convenience getter for the balance in the Pact.
+    function balance() public view returns (uint256) {
+        return address(this).balance;
+    }
+
+    /// @notice Useful for ensuring that the agreement matches the commitment.
     function check(string memory _agreement) public pure returns (bool) {
         return keccak256(bytes(_agreement)) == commitment();
     }

test/MutualAssuranceContract.t.sol

@@ -278,4 +278,28 @@ contract MutualAssuranceContractTest is Test {
         uint256 alicePostBalance = alice.balance;
         assertEq(alicePostBalance, alicePreBalance);
     }
+
+    /// @notice Only allow the Pact to accept the exact amount of ether. This creates a race
+    ///         condition.
+    function test_pact_overflow() external {
+        Pact pact = _deploy();
+
+        uint256 value = pact.sum() - 1;
+
+        vm.expectEmit(true, true, true, true, address(pact));
+        emit Assurance(alice, value);
+
+        vm.prank(alice);
+        (bool success, ) = address(pact).call{ value: value }(hex"");
+        assertTrue(success);
+
+        vm.expectRevert(abi.encodeWithSelector(Pact.Overflow.selector));
+        address(pact).call{ value: 2 }(hex"");
+
+        vm.expectEmit(true, true, true, true, address(pact));
+        emit Assurance(alice, 1);
+
+        vm.prank(alice);
+        (success, ) = address(pact).call{ value: 1 }(hex"");
+    }
 }