raft: raft learners should be returned after applyConfChange

raft/node_test.go

@@ -732,3 +732,55 @@ func TestIsHardStateEqual(t *testing.T) {
 		}
 	}
 }
+
+func TestNodeProposeAddLearnerNode(t *testing.T) {
+	ticker := time.NewTicker(time.Millisecond * 100)
+	defer ticker.Stop()
+	n := newNode()
+	s := NewMemoryStorage()
+	r := newTestRaft(1, []uint64{1}, 10, 1, s)
+	go n.run(r)
+	n.Campaign(context.TODO())
+	stop := make(chan struct{})
+	done := make(chan struct{})
+	applyConfChan := make(chan struct{})
+	go func() {
+		defer close(done)
+		for {
+			select {
+			case <-stop:
+				return
+			case <-ticker.C:
+				n.Tick()
+			case rd := <-n.Ready():
+				s.Append(rd.Entries)
+				t.Logf("raft: %v", rd.Entries)
+				for _, ent := range rd.Entries {
+					if ent.Type != raftpb.EntryConfChange {
+						continue
+					}
+					var cc raftpb.ConfChange
+					cc.Unmarshal(ent.Data)
+					state := n.ApplyConfChange(cc)
+					if len(state.Learners) == 0 ||
+						state.Learners[0] != cc.NodeID ||
+						cc.NodeID != 2 {
+						t.Errorf("apply conf change should return new added learner: %v", state.String())
+					}
+
+					if len(state.Nodes) != 1 {
+						t.Errorf("add learner should not change the nodes: %v", state.String())
+					}
+					t.Logf("apply raft conf %v changed to: %v", cc, state.String())
+					applyConfChan <- struct{}{}
+				}
+				n.Advance()
+			}
+		}
+	}()
+	cc := raftpb.ConfChange{Type: raftpb.ConfChangeAddLearnerNode, NodeID: 2}
+	n.ProposeConfChange(context.TODO(), cc)
+	<-applyConfChan
+	close(stop)
+	<-done
+}