From be8cef5f0e12e41bec53d0e9577e210ace76e779 Mon Sep 17 00:00:00 2001
From: Qiang Zhao <mattisonchao@apache.org>
Date: Tue, 5 Nov 2024 09:36:31 +0800
Subject: [PATCH] fix(server): allow higher term shard deleting (#559)

### Motivation

The coordinator will replace the ensemble when swapping the node.
Therefore, the old node can't receive new term requests, and the actual
shard term will be greater than the old server. and then the old server
will keep printing

```
Invalid term when deleting shard
```

### Modification

- Allow higher term shard deleting.

### Alternatives

- save the deleting term before the new ensemble is elected.
---
 server/follower_controller.go      | 2 +-
 server/follower_controller_test.go | 4 ++--
 server/leader_controller.go        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/server/follower_controller.go b/server/follower_controller.go
index fec148c0..4e2578ba 100644
--- a/server/follower_controller.go
+++ b/server/follower_controller.go
@@ -749,7 +749,7 @@ func (fc *followerController) DeleteShard(request *proto.DeleteShardRequest) (*p
 	fc.Lock()
 	defer fc.Unlock()
 
-	if request.Term != fc.term {
+	if request.Term < fc.term {
 		fc.log.Warn("Invalid term when deleting shard",
 			slog.Int64("follower-term", fc.term),
 			slog.Int64("new-term", request.Term))
diff --git a/server/follower_controller_test.go b/server/follower_controller_test.go
index c93bf4d2..4d640a29 100644
--- a/server/follower_controller_test.go
+++ b/server/follower_controller_test.go
@@ -824,12 +824,12 @@ func TestFollowerController_DeleteShard_WrongTerm(t *testing.T) {
 	walFactory := newTestWalFactory(t)
 
 	fc, _ := NewFollowerController(Config{}, common.DefaultNamespace, shardId, walFactory, kvFactory)
-	_, _ = fc.NewTerm(&proto.NewTermRequest{Term: 1})
+	_, _ = fc.NewTerm(&proto.NewTermRequest{Term: 2})
 
 	_, err := fc.DeleteShard(&proto.DeleteShardRequest{
 		Namespace: common.DefaultNamespace,
 		Shard:     shardId,
-		Term:      2,
+		Term:      1,
 	})
 
 	assert.ErrorIs(t, err, common.ErrorInvalidTerm)
diff --git a/server/leader_controller.go b/server/leader_controller.go
index 5ee6277e..e6beaf30 100644
--- a/server/leader_controller.go
+++ b/server/leader_controller.go
@@ -1090,7 +1090,7 @@ func (lc *leaderController) DeleteShard(request *proto.DeleteShardRequest) (*pro
 	lc.Lock()
 	defer lc.Unlock()
 
-	if request.Term != lc.term {
+	if request.Term < lc.term {
 		lc.log.Warn("Invalid term when deleting shard",
 			slog.Int64("follower-term", lc.term),
 			slog.Int64("new-term", request.Term))