myxce/.wolf/bugs/bug-339.md
Rongsong Shen d26ff8870d
feat(buglog): one Markdown record per bug, checked against a record standard
The buglog was one 27K-line JSON file whose fields covered only symptom,
root cause and fix, as free text: 2% of entries named the code version a
bug was found on, 12% the build profile, 36% a way to reproduce, and 58% of
the file was OpenWolf hook auto-detections ("Missing guard clause",
"Function not marked async" on .md files).

- .claude/skills/buglog/bug-record.md: the record standard. Eight
  sections (Summary as the title, Description, Environment, Reproduction;
  Root cause, Fix, Verification, References once fixed), each with the
  content it must contain -- e.g. Environment needs the OS, the libc the
  failing binary loads (from its ELF interpreter: glibc 2.42 in the nix
  shell vs 2.40 on the host), toolchain, build profile and commit.
- .wolf/bugs/<id>.md: 500 records migrated from buglog.json; every field
  verified to round-trip. They carry legacy: true and an explicit "not
  recorded" where the old log had no such field; component derived from
  file paths, severity from keywords (else unknown), fix_commits from
  hashes in status_note/fix that git resolves (91 of 463 fixed).
- .wolf/buglog-archive.json: the 710 hook auto-detections, verbatim.
- .wolf/buglog.json is now an index generated from the records, keeping
  the fields OpenWolf's hooks and `openwolf bug search` read.
- scripts/buglog.py rewritten: new (template + Environment collected from
  the machine and --binary), check, status (refuses a status the record
  doesn't support; fixed needs Root cause, Fix, Verification and
  --commit hashes git resolves), note, recur, set, show, list, triage,
  env, index. 29 unittest cases in scripts/tests/test_buglog.py.
- scripts/git-hooks/pre-commit runs `check --staged`: incomplete staged
  records, a legacy record hand-changed to fixed without the fix-time
  sections, a new record claiming legacy: true, or a stale index refuse
  the commit.
- scripts/gitea-sync.py reads the records: issue body = the record's
  sections plus linked fix commits (origin remote, GITEA_COMMIT_REPO to
  override), and a body hash so an issue's text is refreshed when the
  record changes.
- bug-1866 rewritten to the full standard as the worked example.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-09-28 03:40:11 +00:00

38 lines
3.2 KiB
Markdown

---
id: "bug-339"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "controller"
severity: "unknown"
timestamp: "2026-06-09T17:30:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 3
files: ["src/controller/ha.c", "src/controller/myapp.c", "src/controller/testsuite/test_ha_rdhup_integration.c"]
tags: ["guard-clause", "c", "raft", "election-safety", "restart", "persistence", "gap-analysis", "ha", "election", "rdhup", "failover", "freshness-gate", "committed_lsn", "applied_lsn", "split-vote", "infinite-loop"]
related: ["bug-338"]
legacy: true
---
# bug-339: After killing the primary in a 3-node controller HA cluster, the two surviving controllers enter…
## Description
After killing the primary in a 3-node controller HA cluster, the two surviving controllers enter an infinite election loop: both only ever raft_cb_become_follower (never become_leader), terms climb in lockstep (4..23), RDHUP -> CTRL_ELECTING -> CTRL_STANDBY repeats forever.
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
LSN-source asymmetry between candidate-advertised LSN and voter freshness floor, specific to the RDHUP failover election path. ha_on_primary_ctrl_fd_rdhup advertised c->persist.committed_lsn as the RequestVote last_log_lsn, but a STANDBY never advances persist.committed_lsn (only the primary's commit engine writes it at persist.c:1192). Standbys advance applied_lsn (ha_apply_wal_catchup_entry) and last_known_committed_lsn (heartbeat replies). The voter-side freshness floor (cluster.c OPCode_requestVote) is max(applied_lsn, last_known_committed_lsn) via ha_vote_self_freshness. So once a standby applied any WAL beyond its last snapshot, every surviving standby advertised a stale-low LSN (e.g. 0) while each peer computed a HIGH floor (e.g. 10); the freshness gate cand_lsn < my_lsn tripped on BOTH sides, each denied the other's vote, neither reached quorum (2 of 3), each election timed out -> become_follower -> 10s liveness timeout -> RDHUP -> re-elect at term+1. The boot path (myapp.c:217) already advertised applied_lsn, so cold-boot election worked; only the RDHUP failover path was inconsistent.
## Fix
In ha_on_primary_ctrl_fd_rdhup, compute candidate freshness ONCE via ha_vote_self_freshness(ha, config_version_tag, applied_lsn, &cand_tag, &cand_lsn) right after ha->raft_c=c, and use cand_tag/cand_lsn for BOTH the elect_ctx (votes[0].my_tag/my_lsn + self_tag/self_lsn) and the XCE_TESTING ha_rdhup_election_hook args. This makes candidate-advertised LSN identical to the voter-side floor, so for any two nodes A,B: A grants B iff floor_B >= floor_A -> the freshest node is always granted by every peer; equal-floor ties are broken by raft priority delay. Regression test added: test_rdhup_candidate_advertises_freshness_floor_not_stale_committed (applied/learned=10, persist.committed=0 -> asserts advertised my_lsn==10). RED (Was 0) -> GREEN verified. Follow-up: boot election path (myapp.c) also routed through ha_vote_self_freshness (was raw applied_lsn) so both election paths are symmetric with the voter floor.
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-338