go: discord/modules: Prevent changed votes from causing a vote to pass/reject

GoBot/discord/modules/vote_result.go

@@ -18,6 +18,8 @@ type confirmedResult struct {
 	IsPositive bool
 }
 
+const invalidVote = -1
+
 var voteMutex sync.Mutex
 var toAnnounceResultList []confirmedResult
 
@@ -25,6 +27,9 @@ func ListenToVoteFinishes(s *discordgo.Session) {
 	for {
 		voteMutex.Lock()
 		for _, v := range toAnnounceResultList {
+			if v.VoteID == invalidVote {
+				continue
+			}
 			message.AuditInfo(s, fmt.Sprintf("Announcing the result of vote %d.", v.VoteID))
 			if err := db.FinishVote(v.VoteID); err != nil {
 				message.AuditError(s, "", err)
@@ -72,13 +77,13 @@ func checkForVoteResult(s *discordgo.Session, id int) {
 	lowestPossible := (currentScore + remainingTrust) / totalGlobalTrust
 	highestPossible := (currentScore + remainingTrust*5) / totalGlobalTrust
 
+	voteMutex.Lock()
+	defer voteMutex.Unlock()
 	if highestPossible <= 3.5 || absoluteRejectionVote {
 		//Rejection confirmed.
-		voteMutex.Lock()
 		for _, v := range toAnnounceResultList {
 			if v.VoteID == id {
 				//It's already queued to be announced in the next announcement cycle.
-				voteMutex.Unlock()
 				return
 			}
 		}
@@ -87,15 +92,11 @@ func checkForVoteResult(s *discordgo.Session, id int) {
 			VoteID:     id,
 			IsPositive: false,
 		})
-		voteMutex.Unlock()
-	}
-	if lowestPossible >= 3.5 {
+	} else if lowestPossible >= 3.5 {
 		//Acceptance confirmed.
-		voteMutex.Lock()
 		for _, v := range toAnnounceResultList {
 			if v.VoteID == id {
 				//It's already queued to be announced in the next announcement cycle.
-				voteMutex.Unlock()
 				return
 			}
 		}
@@ -104,6 +105,17 @@ func checkForVoteResult(s *discordgo.Session, id int) {
 			VoteID:     id,
 			IsPositive: true,
 		})
-		voteMutex.Unlock()
+	} else {
+		//Nothing happened. Make sure it's not in the queue.
+		for k, v := range toAnnounceResultList {
+			if v.VoteID == id {
+				//It's already queued to be announced in the next announcement cycle.
+				toAnnounceResultList[k] = confirmedResult{
+					VoteID:     invalidVote,
+					IsPositive: false,
+				}
+				return
+			}
+		}
 	}
 }