(kvrocks) branch unstable updated: fix(server): avoid ROLE crash when the DB is closed during full sync (#3667)

[hulk]

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git-hulk pushed a commit to branch unstable
in repository https://gitbox.apache.org/repos/asf/kvrocks.git


The following commit(s) were added to refs/heads/unstable by this push:
     new 12fc17a75 fix(server): avoid ROLE crash when the DB is closed during 
full sync (#3667)
12fc17a75 is described below

commit 12fc17a756e46bce39889177b8176467f24e67da
Author: jonas <jonas...@gmail.com>
AuthorDate: Wed Oct 14 14:42:46 2026 +0800

    fix(server): avoid ROLE crash when the DB is closed during full sync (#3667)
    
    This closes #3666
    
    ## Summary
    
    `ROLE` is registered with `ok-loading`, so it runs while the server is
    loading. During a full sync, `Server::PrepareRestoreDB()` closes the DB
    (`db_ = nullptr`) and only reopens it after the checkpoint is restored.
    Any `ROLE` executed in this window dereferences the null `db_` in
    `Storage::LatestSeqNumber()` and the process dies with SIGSEGV.
    
    ## Fix
    
    Align `ROLE` with `INFO`: in the slave branch of `GetRoleInfo()`, skip
    reading the sequence number while `is_loading_` is set and report the
    offset as `0`.
    
    ## AI Usage Disclosure
    
    - The coredump analysis and the fix were implemented manually.
    - AI tools (Kimi K3) were used to assist in code review; all review
    suggestions were checked by the author.
    
    Co-authored-by: Twice <twice.m...@gmail.com>
---
 src/server/server.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/server/server.cc b/src/server/server.cc
index cbb7bd120..7842c5a81 100644
--- a/src/server/server.cc
+++ b/src/server/server.cc
@@ -1335,7 +1335,11 @@ std::string Server::GetRoleInfo() {
     } else {
       roles.emplace_back("connecting");
     }
-    roles.emplace_back(std::to_string(storage->LatestSeqNumber()));
+    std::string latest_seq_str = "0";
+    if (!is_loading_) {
+      latest_seq_str = std::to_string(storage->LatestSeqNumber());
+    }
+    roles.emplace_back(latest_seq_str);
     return redis::ArrayOfBulkStrings(roles);
   } else {
     std::vector<std::string> list;