myxce/.wolf/bugs/bug-828.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

39 lines
4.1 KiB
Markdown

---
id: "bug-828"
status: "fixed"
status_updated: "2026-09-24"
status_note: "91b9a445, b77d4122"
component: "controller"
severity: "unknown"
timestamp: "2026-06-20T10:19:56.678Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 3
files: ["src/controller/ha.c (vote_reply_dispatch)", "src/controller/persist.c (persist_wal_write_replicated)"]
tags: ["async-fix", "md", "data-loss", "failover", "committed-job-loss", "wal", "catch-up", "snapshot", "ha-commit-durability", "bug-795", "architecture", "NOT-FIXED", "safety", "safe-committed-lsn", "vote-reply", "leader-completeness", "ha-repl-hardening", "PARTIAL-FIX", "c"]
related: ["bug-795", "bug-851"]
fix_commits: ["91b9a445", "b77d4122"]
legacy: true
---
# bug-828: Clean single failover under-computes safe_committed_lsn: new leader logs 'safe_committed_lsn=1 ...…
## Description
Clean single failover under-computes safe_committed_lsn: new leader logs 'safe_committed_lsn=1 ... (from 1 granted voters)' (self only) and truncates committed entries down to its own boot floor. Post-election safe-commit-from-votes plumbing was DEAD in production.
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
vote_reply_decode_and_dispatch decoded the granting voter's advertised peerLastLogLsn (vr_lsn at ha.c ~4254) but vote_reply_dispatch DISCARDED it ('(void)peer_lsn; raft_on_vote_reply(...)'). raft_on_vote_reply only bumps s->votes_granted; it never records the peer LSN. The only writer of ctx->votes[idx].vote_granted/peer_lsn (handle_request_vote_reply) was, in production, called ONLY from the connect/error failure paths with (granted=0, lsn=0); the real-grant caller was gated behind a test-only hook (xce_vote_reply_hook, never set in production). So ctx->votes[*] stayed calloc'd zero -> ha_compute_safe_committed_lsn saw n_granted=1 (self) -> safe_committed_lsn = self_lsn. A standby promoting with its own durable_floor=1 then persist_truncate_wal_above(1) destroyed committed LSN 2..5.
## Fix
PRIMARY: in vote_reply_dispatch production branch, route the decoded reply into the election context via a NEW record-only seam ha_record_vote_reply(ha,ctx,idx,term,granted,tag,lsn) BEFORE raft_on_vote_reply. Factored ha_record_vote_reply_locked out of handle_request_vote_reply: it records ctx->votes[idx] under ctx->lock with the idempotency guard but does NOT call ha_elect_evaluate_and_signal -> no second/racing legacy promotion path (raft_on_vote_reply remains the SOLE production promotion driver; the two quorum tallies (raft s->votes_granted / legacy ctx->votes_granted) and their guards (s->election_decided / ctx->done_posted) stay independent and idempotent). idx == vctx->peer_idx == the local ctx->votes[] index (absolute->local map done in raft_cb_send_vote_request), exactly the index ha_compute_safe_committed_lsn + the test hook use. SECONDARY: persist_wal_write_replicated now advances durable_lsn to the synced tip immediately after the inline fdatasync (mirror persist_flush; monotonic max; fail-loud rc-gated) so a standby advertises its own synced durable floor without waiting for the 10ms cadence flusher. VERIFIED: unit test_safe_commit_reflects_granting_voter_lsn RED (safe=1 'from 1 granted voters') -> GREEN (safe=5 'from 3 granted voters'); 177/177 controller_unit_test pass. NOTE: the LIVE clean_failover_preservation harness still FAILS, but the failure is PRE-EXISTING on baseline 14c41cb (verified by stash+rerun: baseline runs also diverge / lose jobs) — it is the SEPARATE bug-795/828 replication+catch-up gap (standbys' WALs physically contain only LSN 1..2, durable_floor=1; committed entries 2..5 never reach the standby WAL; primary advanced committed_lsn to 5 without a standby durable at 5). The fix DID change the live fingerprint from 'from 1 granted voters' to 'from 2 granted voters', proving the plumbing is now alive. safe-commit-from-votes is correct; the residual live job loss is out of scope (needs the catch-up/snapshot-backfill fix tracked under ha-commit-durability).
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-795, bug-851