reverts

packages/contracts/src/MajorityVotingBase.sol

@@ -261,6 +261,10 @@ abstract contract MajorityVotingBase is
     /// @param sender The sender address.
     error ProposalCreationForbidden(address sender);
 
+    /// @notice Thrown when a proposal doesn't exist.
+    /// @param proposalId The ID of the proposal which doesn't exist.
+    error NonexistentProposal(uint256 proposalId);
+
     /// @notice Thrown if an account is not allowed to cast a vote. This can be because the vote
     /// - has not started,
     /// - has ended,
@@ -387,18 +391,30 @@ abstract contract MajorityVotingBase is
         address _voter,
         VoteOption _voteOption
     ) public view virtual returns (bool) {
+        if (!_proposalExists(_proposalId)) {
+            revert NonexistentProposal(_proposalId);
+        }
+
         return _canVote(_proposalId, _voter, _voteOption);
     }
 
     /// @inheritdoc IMajorityVoting
     function canExecute(
         uint256 _proposalId
     ) public view virtual override(IMajorityVoting) returns (bool) {
+        if (!_proposalExists(_proposalId)) {
+            revert NonexistentProposal(_proposalId);
+        }
+
         return _canExecute(_proposalId);
     }
 
     /// @inheritdoc IProposal
     function hasSucceeded(uint256 _proposalId) public view virtual returns (bool) {
+        if (!_proposalExists(_proposalId)) {
+            revert NonexistentProposal(_proposalId);
+        }
+
         return _hasSucceeded(_proposalId);
     }
 
@@ -413,6 +429,8 @@ abstract contract MajorityVotingBase is
             proposal_.parameters.supportThreshold * proposal_.tally.no;
     }
 
+    // is it possible that isSupportThresholdReachedEarly returns true, where isSupportThresholdReached returns false
+
     /// @inheritdoc IMajorityVoting
     function isSupportThresholdReachedEarly(
         uint256 _proposalId
@@ -695,6 +713,13 @@ abstract contract MajorityVotingBase is
         });
     }
 
+    /// @notice Checks if proposal exists or not.
+    /// @param _proposalId The ID of the proposal.
+    /// @return Returns `true` if proposal exists, otherwise false.
+    function _proposalExists(uint256 _proposalId) private view returns (bool) {
+        return proposals[_proposalId].parameters.snapshotBlock != 0;
+    }
+
     /// @notice Internal function to update minimal approval value.
     /// @param _minApprovals The new minimal approval value.
     function _updateMinApprovals(uint256 _minApprovals) internal virtual {

packages/contracts/test/10_unit-testing/11_plugin.ts

@@ -1483,8 +1483,10 @@ describe('TokenVoting', function () {
       expect(proposal.tally.no).to.equal(0);
       expect(proposal.tally.abstain).to.equal(0);
 
-      expect(await plugin.canVote(1, alice.address, VoteOption.Yes)).to.equal(
-        false
+      expect(await plugin.canVote(id, alice.address, VoteOption.Yes)).to.be
+        .true;
+      expect(await plugin.getVoteOption(id, alice.address)).to.equal(
+        VoteOption.None
       );
 
       expect(proposal.actions.length).to.equal(1);
@@ -1649,6 +1651,24 @@ describe('TokenVoting', function () {
         dummyMetadata: string;
       }>
     ) {
+      it('reverts if proposal does not exist', async () => {
+        const {initializedPlugin: plugin} = await loadFixture(localFixture);
+
+        const id = 10;
+
+        await expect(plugin.canExecute(id))
+          .to.be.revertedWithCustomError(plugin, 'NonexistentProposal')
+          .withArgs(id);
+
+        await expect(plugin.canVote(id, plugin.address, VoteOption.Yes))
+          .to.be.revertedWithCustomError(plugin, 'NonexistentProposal')
+          .withArgs(id);
+
+        await expect(plugin.hasSucceeded(id))
+          .to.be.revertedWithCustomError(plugin, 'NonexistentProposal')
+          .withArgs(id);
+      });
+
       it('does not allow voting, when the vote has not started yet', async () => {
         const {
           alice,