myxce/.wolf/bugs/bug-1023.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
3.4 KiB
Markdown

---
id: "bug-1023"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "controller"
severity: "unknown"
timestamp: "2026-06-23T03:45:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/controller/ha.c"]
tags: ["ha", "raft", "failover", "leader-completeness", "bug-828", "bug-795", "durability", "truncate", "election", "durable_lsn"]
related: ["bug-661", "bug-795", "bug-828", "bug-851", "bug-854", "bug-339"]
legacy: true
---
# bug-1023: Clean single failover (STRICT_TERM) loses committed jobs: safe_committed_lsn=1 from votes despite…
## Description
Clean single failover (STRICT_TERM) loses committed jobs: safe_committed_lsn=1 from votes despite a standby being genuinely durable at LSN 5; walcompare reports committed-prefix divergence at LSN 2 (jobs gone on the new leader).
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
ha_enter_real_election() PRE-TRUNCATED the candidate's WAL above ha->last_known_committed_lsn BEFORE the vote. last_known_committed_lsn is the LOCALLY-LEARNED commit watermark, which LAGS the true cluster commit point (the primary commits an entry on a durable majority, then dies before a heartbeat carries that committed LSN to the standby). persist_truncate_wal_above clamps durable_lsn down to the cutoff (clamp_durable_lsn_locked). So a standby durably holding committed entries [committed+1..tip] discarded them, then advertised the stale-low cutoff as its durable floor (ha_candidate_advertise_lsn / ha_vote_self_freshness both read persist_durable_floor). Every voter doing the same collapsed safe-committed-from-votes to the stale watermark; the AUTHORITATIVE post-election truncate (raft_cb_become_leader -> persist_truncate_wal_above(safe_committed_lsn)) then kept only that stale prefix, losing committed jobs. Live trace (DBG828) PROVED the standbys wrote+fdatasync'd LSN 2-5 (durable_lsn=5) and only LOST them at the pre-election truncate clamp — NOT a durability/ack-before-fsync violation. Final bug-828/795 slice.
## Fix
Removed the pre-election persist_truncate_wal_above(last_known_committed_lsn) in ha_enter_real_election (src/controller/ha.c). Raft model: a candidate does NOT truncate its log before campaigning — it keeps its full durable log and advertises its real durable tip so voters holding more committed entries deny a colder candidate and the winner has every committed entry (Leader Completeness). Divergent UNCOMMITTED tails are removed only by the authoritative post-election safe-commit truncate (above the majority-held point) and by the library's per-entry (term,lsn) reconcile (on_truncate_from) during AppendEntries. RED: live STRICT_TERM harness safe=1 + walcompare divergence at LSN 2. GREEN: every run now logs safe_committed_lsn=5 (from 2 granted voters) and walcompare 'committed prefixes identical'. Unit: new test_repl_catchup_durable_floor_survives_failover (test_repl_apply.c) + 177/177 unit GREEN. NOTE: live EXIT still 1 due to a PRE-EXISTING libxce client-failover bug (bug: 'client op fails to reach live primary when a DEAD controller is FIRST in the masters list') surfacing now that the durability bug no longer masks the post-walcompare expect-job/wait-primary step — committed jobs are physically present on disk (walcompare proves it).
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-661, bug-795, bug-828, bug-851, bug-854, bug-339