address comment

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>

harness/tests/integration_cases/test_raft.rs

@@ -4728,26 +4728,28 @@ fn test_request_snapshot_on_role_change() {
 /// Tests group commit.
 ///
 /// 1. Logs should be replicated to at least different groups before committed;
-/// 2. If no groups has been configured, quorum should be used.
+/// 2. If no group is configured or all peers are configured to the same group,
+///     simple quorum should be used.
 #[test]
 fn test_group_commit() {
     let l = default_logger();
     let mut tests = vec![
-        // single
+        // Single
         (vec![1], vec![0], 1),
         (vec![1], vec![1], 1),
-        // odd
+        // Odd
         (vec![2, 2, 1], vec![1, 2, 1], 2),
         (vec![2, 2, 1], vec![1, 1, 2], 1),
         (vec![2, 2, 1], vec![1, 0, 1], 1),
         (vec![2, 2, 1], vec![0, 0, 0], 2),
-        // even
+        // Even
         (vec![4, 2, 1, 3], vec![0, 0, 0, 0], 2),
         (vec![4, 2, 1, 3], vec![1, 0, 0, 0], 1),
         (vec![4, 2, 1, 3], vec![0, 1, 0, 2], 2),
         (vec![4, 2, 1, 3], vec![0, 2, 1, 0], 1),
         (vec![4, 2, 1, 3], vec![1, 1, 1, 1], 2),
         (vec![4, 2, 1, 3], vec![1, 1, 2, 1], 1),
+        (vec![4, 2, 1, 3], vec![1, 2, 1, 1], 2),
         (vec![4, 2, 1, 3], vec![4, 3, 2, 1], 2),
     ];
 

src/raft.rs

@@ -405,7 +405,7 @@ impl<T: Storage> Raft<T> {
             if let Some(pr) = self.mut_prs().get_mut(*peer_id) {
                 pr.commit_group_id = *group_id;
             } else {
-                return;
+                continue;
             }
         }
         if StateRole::Leader == self.state && self.maybe_commit() {
@@ -437,7 +437,7 @@ impl<T: Storage> Raft<T> {
         if !self.apply_to_current_term() {
             return None;
         }
-        let (index, use_group_commit) = self.prs.as_mut().unwrap().maximal_committed_index();
+        let (index, use_group_commit) = self.mut_prs().maximal_committed_index();
         debug!(
             self.logger,
             "check group commit consistent";
@@ -721,7 +721,7 @@ impl<T: Storage> Raft<T> {
     /// Attempts to advance the commit index. Returns true if the commit index
     /// changed (in which case the caller should call `r.bcast_append`).
     pub fn maybe_commit(&mut self) -> bool {
-        let mci = self.prs.as_mut().unwrap().maximal_committed_index().0;
+        let mci = self.mut_prs().maximal_committed_index().0;
         self.raft_log.maybe_commit(mci, self.term)
     }