Make Votes._getVotingUnits view (#3225)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

CHANGELOG.md

@@ -16,6 +16,7 @@
 * `Governor`: Adds internal virtual `_getVotes` method that must be implemented; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing voting module extension, rename `getVotes` to `_getVotes` and add a `bytes memory` argument. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
 * `Governor`: Adds `params` parameter to internal virtual `_countVote ` method; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing counting module extension, add a `bytes memory` argument to `_countVote`. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
 * `Governor`: Does not emit `VoteCast` event when params data is non-empty; instead emits `VoteCastWithParams` event. To fix this on an integration that consumes the `VoteCast` event, also fetch/monitor `VoteCastWithParams` events. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
+* `Votes`: The internal virtual function `_getVotingUnits` was made `view` (which was accidentally missing). Any overrides should now be updated so they are `view` as well.
 
 ## 4.5.0 (2022-02-09)
 

contracts/governance/utils/Votes.sol

@@ -207,5 +207,5 @@ abstract contract Votes is IVotes, Context, EIP712 {
     /**
      * @dev Must return the voting units held by an account.
      */
-    function _getVotingUnits(address) internal virtual returns (uint256);
+    function _getVotingUnits(address) internal view virtual returns (uint256);
 }

contracts/mocks/VotesMock.sol

@@ -18,7 +18,7 @@ contract VotesMock is Votes {
         return _delegate(account, newDelegation);
     }
 
-    function _getVotingUnits(address account) internal virtual override returns (uint256) {
+    function _getVotingUnits(address account) internal view virtual override returns (uint256) {
         return _balances[account];
     }
 

contracts/token/ERC721/extensions/draft-ERC721Votes.sol

@@ -34,7 +34,7 @@ abstract contract ERC721Votes is ERC721, Votes {
     /**
      * @dev Returns the balance of `account`.
      */
-    function _getVotingUnits(address account) internal virtual override returns (uint256) {
+    function _getVotingUnits(address account) internal view virtual override returns (uint256) {
         return balanceOf(account);
     }
 }