fix: modify message vote tss to allow operators to vote on ballots assosiated with discarded keygen .

changelog.md

@@ -20,6 +20,7 @@
 ### Fixes
 
 * [2654](https://github.com/zeta-chain/node/pull/2654) - add validation for authorization list in when validating genesis state for authorization module
+* [2674](https://github.com/zeta-chain/node/pull/2674) - allow operators to vote on ballots assosiated with discarded keygen without affecting the status of the current keygen.
 
 ## v19.0.0
 

x/observer/keeper/msg_server_vote_tss.go

@@ -42,11 +42,6 @@ func (k msgServer) VoteTSS(goCtx context.Context, msg *types.MsgVoteTSS) (*types
 		return &types.MsgVoteTSSResponse{}, errorsmod.Wrap(types.ErrKeygenNotFound, voteTSSid)
 	}
 
-	// Use a separate transaction to update keygen status to pending when trying to change the TSS address.
-	if keygen.Status == types.KeygenStatus_KeyGenSuccess {
-		return &types.MsgVoteTSSResponse{}, errorsmod.Wrap(types.ErrKeygenCompleted, voteTSSid)
-	}
-
 	// GetBallot checks against the supported chains list before querying for Ballot.
 	ballotCreated := false
 	index := msg.Digest()
@@ -94,6 +89,21 @@ func (k msgServer) VoteTSS(goCtx context.Context, msg *types.MsgVoteTSS) (*types
 		}, nil
 	}
 
+	// The ballot is finalized, we check if this is the correct ballot for updating the TSS
+	// The requirements are
+	// 1. The keygen is still pending
+	// 2. The keygen block number matches the ballot block number ,which makes sure this the correct ballot for the current keygen
+
+	// Return without error so the vote is added to the ballot
+	if keygen.Status != types.KeygenStatus_PendingKeygen {
+		return &types.MsgVoteTSSResponse{}, nil
+	}
+
+	// For cases when an observer tries to vote for an older pending ballot , associated with a keygen that was discarded , we would return at this check while still adding the vote to the ballot
+	if msg.KeygenZetaHeight != keygen.BlockNumber {
+		return &types.MsgVoteTSSResponse{}, nil
+	}
+
 	// Set TSS only on success, set keygen either way.
 	// Keygen block can be updated using a policy transaction if keygen fails.
 	keygenSuccess := false