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src/FlexVotingClient.sol

@@ -88,6 +88,11 @@ abstract contract FlexVotingClient {
   /// given time.
   Checkpoints.Trace208 internal totalBalanceCheckpoints;
 
+  error FlexVotingClient__NoVotingWeight();
+  error FlexVotingClient__AlreadyVoted();
+  error FlexVotingClient__InvalidSupportValue();
+  error FlexVotingClient__NoVotesExpressed();
+
   /// @param _governor The address of the flex-voting-compatible governance contract.
   constructor(address _governor) {
     GOVERNOR = IFractionalGovernor(_governor);
@@ -116,9 +121,9 @@ abstract contract FlexVotingClient {
   /// @param support The depositor's vote preferences in accordance with the `VoteType` enum.
   function expressVote(uint256 proposalId, uint8 support) external {
     uint256 weight = getPastRawBalance(msg.sender, GOVERNOR.proposalSnapshot(proposalId));
-    require(weight > 0, "no weight");
+    if (weight == 0) revert FlexVotingClient__NoVotingWeight();
 
-    require(!proposalVotersHasVoted[proposalId][msg.sender], "already voted");
+    if (proposalVotersHasVoted[proposalId][msg.sender]) revert FlexVotingClient__AlreadyVoted();
     proposalVotersHasVoted[proposalId][msg.sender] = true;
 
     if (support == uint8(VoteType.Against)) {
@@ -128,7 +133,8 @@ abstract contract FlexVotingClient {
     } else if (support == uint8(VoteType.Abstain)) {
       proposalVotes[proposalId].abstainVotes += SafeCast.toUint128(weight);
     } else {
-      revert("invalid support value, must be included in VoteType enum");
+      // Support value must be included in VoteType enum.
+      revert FlexVotingClient__InvalidSupportValue();
     }
   }
 
@@ -139,10 +145,10 @@ abstract contract FlexVotingClient {
   /// @param proposalId The ID of the proposal which the Pool will now vote on.
   function castVote(uint256 proposalId) external {
     ProposalVote storage _proposalVote = proposalVotes[proposalId];
-    require(
-      _proposalVote.forVotes + _proposalVote.againstVotes + _proposalVote.abstainVotes > 0,
-      "no votes expressed"
-    );
+    if (_proposalVote.forVotes + _proposalVote.againstVotes + _proposalVote.abstainVotes == 0) {
+      revert FlexVotingClient__NoVotesExpressed();
+    }
+
     uint256 _proposalSnapshotBlockNumber = GOVERNOR.proposalSnapshot(proposalId);
 
     // We use the snapshot of total raw balances to determine the weight with

test/FlexVotingClient.t.sol

@@ -9,6 +9,7 @@ import {IGovernor} from "@openzeppelin/contracts/governance/Governor.sol";
 import {IVotingToken} from "src/interfaces/IVotingToken.sol";
 import {IFractionalGovernor} from "src/interfaces/IFractionalGovernor.sol";
 import {GovernorCountingFractional as GCF} from "src/GovernorCountingFractional.sol";
+import {FlexVotingClient as FVC} from "src/FlexVotingClient.sol";
 import {MockFlexVotingClient} from "test/MockFlexVotingClient.sol";
 import {GovToken} from "test/GovToken.sol";
 import {FractionalGovernor} from "test/FractionalGovernor.sol";
@@ -502,7 +503,7 @@ contract ExpressVote is FlexVotingClientTest {
 
     // Now try to express a voting preference on the proposal.
     assertEq(flexClient.deposits(_user), _voteWeight);
-    vm.expectRevert(bytes("no weight"));
+    vm.expectRevert(FVC.FlexVotingClient__NoVotingWeight.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, uint8(_voteType));
   }
@@ -524,7 +525,7 @@ contract ExpressVote is FlexVotingClientTest {
     uint256 _proposalId = _createAndSubmitProposal();
 
     // _user should NOT be able to express his/her vote on the proposal.
-    vm.expectRevert(bytes("no weight"));
+    vm.expectRevert(FVC.FlexVotingClient__NoVotingWeight.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, uint8(_voteType));
 
@@ -536,7 +537,7 @@ contract ExpressVote is FlexVotingClientTest {
     // _user should still NOT be able to express his/her vote on the proposal.
     // Despite having a deposit balance, he/she didn't have a balance at the
     // proposal snapshot.
-    vm.expectRevert(bytes("no weight"));
+    vm.expectRevert(FVC.FlexVotingClient__NoVotingWeight.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, uint8(_voteType));
   }
@@ -567,7 +568,7 @@ contract ExpressVote is FlexVotingClientTest {
     assertEq(_abstainVotesExpressedInit, _voteType == GCF.VoteType.Abstain ? _voteWeight : 0);
 
     // Vote early and often!
-    vm.expectRevert(bytes("already voted"));
+    vm.expectRevert(FVC.FlexVotingClient__AlreadyVoted.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, uint8(_voteType));
 
@@ -595,7 +596,7 @@ contract ExpressVote is FlexVotingClientTest {
     uint256 _proposalId = _createAndSubmitProposal();
 
     // Now try to express a voting preference with a bogus support type.
-    vm.expectRevert(bytes("invalid support value, must be included in VoteType enum"));
+    vm.expectRevert(FVC.FlexVotingClient__InvalidSupportValue.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, _supportType);
   }
@@ -626,7 +627,7 @@ contract ExpressVote is FlexVotingClientTest {
     assert(_proposalId != _id);
 
     // Now try to express a voting preference on the bogus proposal.
-    vm.expectRevert("no weight");
+    vm.expectRevert(FVC.FlexVotingClient__NoVotingWeight.selector);
     vm.prank(_user);
     flexClient.expressVote(_proposalId, _supportType);
   }
@@ -1077,7 +1078,7 @@ contract CastVote is FlexVotingClientTest {
     uint256 _proposalId = _createAndSubmitProposal();
 
     // No one has expressed, there are no votes to cast.
-    vm.expectRevert(bytes("no votes expressed"));
+    vm.expectRevert(FVC.FlexVotingClient__NoVotesExpressed.selector);
     flexClient.castVote(_proposalId);
 
     // _user expresses his/her vote on the proposal.
@@ -1088,7 +1089,7 @@ contract CastVote is FlexVotingClientTest {
     flexClient.castVote(_proposalId);
 
     // All votes have been cast, there's nothing new to send to the governor.
-    vm.expectRevert(bytes("no votes expressed"));
+    vm.expectRevert(FVC.FlexVotingClient__NoVotesExpressed.selector);
     flexClient.castVote(_proposalId);
   }