add revoke_vote method (#36)

Co-authored-by: Amit Yadav <[email protected]>
Co-authored-by: Robert Zaremba <[email protected]>

elections/README.md

@@ -7,8 +7,9 @@
 - Only the authority (set during contract initialization) can create proposals. Each proposal specifies:
 
   - `typ`: must be HouseType variant
-  - `start`: voting start time as UNIX time (in seconds)
-  - `end`: voting start time as UNIX time (in seconds)
+  - `start`: voting start time as UNIX time (in miliseconds)
+  - `end`: voting start time as UNIX time (in miliseconds)
+  - `cooldown`: cooldown duration when votes from blacklisted accounts can be revoked by an authority (in miliseconds)
   - `ref_link`: string (can't be empty) - a link to external resource with more details (eg near social post). Max length is 120 characters.
   - `quorum`: minimum amount of legit accounts to vote to legitimize the elections.
   - `seats`: max number of candidates to elect, also max number of credits each user has when casting a vote.
@@ -21,6 +22,7 @@
 - Once the proposals are created and the elections start (`now >= proposal.start`), all human verified near accounts can vote according to the NDC Elections [v1 Framework](../README.md#elections).
 - Anyone can query the proposal and the ongoing result at any time.
 - Voting is active until the `proposal.end` time.
+- Vote revocation is active until the `proposal.end` + `cooldown` time.
 
 ## Usage
 
@@ -31,9 +33,9 @@ CTR=elections-v1.gwg.testnet
 REGISTRY=registry-1.i-am-human.testnet
 
 # create proposal
-# note: start and end time must be in milliseconds
+# note: start time, end time and cooldown must be in milliseconds
 
-near call $CTR create_proposal '{"start": 1686221747000, "end": 1686653747000, "ref_link": "example.com", "quorum": 10, "candidates": ["candidate1.testnet", "candidate2.testnet", "candidate3.testnet", "candidate4.testnet"], "typ": "HouseOfMerit", "seats": 3, "policy": "f1c09f8686fe7d0d798517111a66675da0012d8ad1693a47e0e2a7d3ae1c69d4"}' --accountId $CTR
+near call $CTR create_proposal '{"start": 1686221747000, "end": 1686653747000, "cooldown": 604800000  "ref_link": "example.com", "quorum": 10, "candidates": ["candidate1.testnet", "candidate2.testnet", "candidate3.testnet", "candidate4.testnet"], "typ": "HouseOfMerit", "seats": 3, "policy": "f1c09f8686fe7d0d798517111a66675da0012d8ad1693a47e0e2a7d3ae1c69d4"}' --accountId $CTR
 
 # fetch all proposal
 near view $CTR proposals ''
@@ -49,6 +51,9 @@ near call $CTR accepted_policy '{"user": "alice.testnet"}' --accountId me.testne
 
 # vote
 near call $CTR vote '{"prop_id": 1, "vote": ["candidate1.testnet", "candidate3.testnet"]}' --gas 70000000000000 --deposit 0.0005 --accountId me.testnet
+
+# revoke vote (authority only)
+near call $CTR revoke_vote '{"prop_id": 1, "token_id": 1}'
 ```
 
 ## Deployed Contracts

elections/src/errors.rs

@@ -11,6 +11,9 @@ pub enum VoteError {
     NoSBTs,
     DuplicateCandidate,
     DoubleVote(TokenId),
+    RevokeNotActive,
+    NotVoted,
+    DoubleRevoke,
 }
 
 impl FunctionError for VoteError {
@@ -24,6 +27,11 @@ impl FunctionError for VoteError {
             VoteError::DoubleVote(sbt) => {
                 panic_str(&format!("user already voted with sbt={}", sbt))
             }
+            VoteError::RevokeNotActive => panic_str(
+                "can only revoke votes between proposal start and (end time + cooldown)"
+            ),
+            VoteError::NotVoted => panic_str("voter did not vote on this proposal"),
+            VoteError::DoubleRevoke => panic_str("vote already revoked"),
         }
     }
 }

elections/src/lib.rs

@@ -58,6 +58,7 @@ impl Contract {
         typ: HouseType,
         start: u64,
         end: u64,
+        cooldown: u64,
         ref_link: String,
         quorum: u32,
         seats: u16,
@@ -90,13 +91,15 @@ impl Contract {
             typ,
             start,
             end,
+            cooldown,
             quorum,
             ref_link,
             seats,
             candidates,
             result: vec![0; l],
             voters: LookupSet::new(StorageKey::ProposalVoters(self.prop_counter)),
             voters_num: 0,
+            voters_candidates: LookupMap::new(StorageKey::VotersCandidates(self.prop_counter)),
             policy,
         };
 
@@ -153,6 +156,18 @@ impl Contract {
             )
     }
 
+    /// Method for the authority to revoke votes from blacklisted accounts.
+    /// Panics if the proposal doesn't exists or the it's called before the proposal starts or after proposal `end+cooldown`.
+    #[handle_result]
+    pub fn revoke_vote(&mut self, prop_id: u32, token_id: TokenId) -> Result<(), VoteError> {
+        // check if the caller is the authority allowed to revoke votes
+        self.assert_admin();
+        let mut p = self._proposal(prop_id);
+        p.revoke_votes(token_id)?;
+        self.proposals.insert(&prop_id, &p);
+        Ok(())
+    }
+
     /*****************
      * QUERIES
      ****************/
@@ -280,6 +295,7 @@ mod unit_tests {
             crate::HouseType::HouseOfMerit,
             START - 1,
             START + 100,
+            100,
             String::from("ref_link.io"),
             2,
             2,
@@ -297,6 +313,7 @@ mod unit_tests {
             crate::HouseType::HouseOfMerit,
             START + 10,
             START,
+            100,
             String::from("ref_link.io"),
             2,
             2,
@@ -314,6 +331,7 @@ mod unit_tests {
             crate::HouseType::HouseOfMerit,
             START + 1,
             START + 10,
+            100,
             String::from("short"),
             2,
             2,
@@ -331,6 +349,7 @@ mod unit_tests {
             crate::HouseType::HouseOfMerit,
             START + 1,
             START + 10,
+            100,
             String::from("ref_link.io"),
             2,
             2,
@@ -344,6 +363,7 @@ mod unit_tests {
             crate::HouseType::HouseOfMerit,
             START + 1,
             START + 10,
+            100,
             String::from("ref_link.io"),
             2,
             2,
@@ -648,4 +668,36 @@ mod unit_tests {
         ctr.vote(prop_id, vec![]);
         // note: we can only check vote result and state change through an integration test.
     }
+
+    #[test]
+    #[should_panic(expected = "not an admin")]
+    fn revoke_vote_not_admin() {
+        let (_, mut ctr) = setup(&alice());
+        let prop_id = mk_proposal(&mut ctr);
+        let res = ctr.revoke_vote(prop_id, 1);
+        // this will never be checked since the method is panicing not returning an error
+        assert!(res.is_err());
+    }
+
+    #[test]
+    fn revoke_vote_no_votes() {
+        let (mut ctx, mut ctr) = setup(&admin());
+        let prop_id = mk_proposal(&mut ctr);
+        ctx.block_timestamp = (START + 100) * MSECOND;
+        testing_env!(ctx);
+        match ctr.revoke_vote(prop_id, 1) {
+            Err(VoteError::NotVoted) => (),
+            x => panic!("expected NotVoted, got: {:?}", x),
+        }
+    }
+
+    #[test]
+    #[should_panic(expected = "proposal not found")]
+    fn revoke_vote_no_proposal() {
+        let (_, mut ctr) = setup(&admin());
+        let prop_id = 2;
+        match ctr.revoke_vote(prop_id, 1) {
+            x => panic!("{:?}", x),
+        }
+    }
 }