myxce/.wolf/bugs/bug-1416.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
9.1 KiB
Markdown

---
id: "bug-1416"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "controller"
severity: "unknown"
timestamp: "2026-07-05T06:15:00.000Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 11
files: ["src/controller/persist.c (persist_verify_apply_correctness / persist_recover", "cluster.c cluster_init_phase2)"]
tags: ["raft-apply-decoupling", "task-7.2", "xce-test-ha", "factstream", "persist_recover", "APPLY_DIVERGENT", "false-positive-candidate", "boot-race", "concurrency", "live-regression-found", "recovery-complete-gate", "myapp-boot-sequencing"]
related: ["bug-1409", "bug-1415"]
legacy: true
---
# bug-1416: [xce-test-ha] FAIL: factstream round 1: cluster did not reconverge to 3-of-3 after restarting…
## Description
[xce-test-ha] FAIL: factstream round 1: cluster did not reconverge to 3-of-3 after restarting ctrl-1 -- root cause: persist_recover: APPLY_DIVERGENT -- materialized state does not match the committed log tip (expected last_applied_lsn=72 new_job_count=23); persist_recover_loud_fence_if_unrecoverable: UNRECOVERABLE, staying alive/non-promotable
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
Found live via the new raft-apply-decoupling task 7.2 kill-mid-fact-stream soak scenario (--factstream), reproduced 4/4 runs (ASAN debug build, paced-wave ASAN build, release build, and a cleanup-suppressed debug postmortem run) in this sandboxed environment. cluster_init_phase2() calls cluster_open_listener() (which starts accepting network I/O, including replicated/catch-up WAL traffic from an already-serving primary) BEFORE persist_recover() runs its boot-time apply-correctness verification (task 5.1, Req 8.1/8.2). Under a slow/contended boot (observed: persist_recover firing ~36s after process start instead of the normal ~5s, plausibly due to heavy concurrent nix-develop/test-process CPU contention in this sandbox), a standby's listener can already be live and processing real traffic for tens of seconds before its own persist_recover() call finally executes. persist_verify_apply_correctness() (persist.c ~3597) reads p->last_applied_lsn and live-queries count_jobmgr_entries(p->cluster) AFTER replay_wal completes -- both of these are also mutated by the LIVE apply pump (raft-apply-decoupling task 6.1, wired through commit_resolve_pending) reacting to replicated commit-advance events. If live traffic is already flowing and being applied through the live pump DURING the extended pre-persist_recover window, the live-read 'actual' values used by persist_verify_apply_correctness can reflect state beyond what persist_recover's own single WAL-scan pass computed as 'expected', producing a DIVERGENT verdict even though no real apply defect exists -- confirmed via ctrlstatus probes showing committedLsn identical (79) and no actual data loss across all 3 nodes; the fence engaged correctly per its own fail-loud design (stayed alive, non-promotable, kept retrying) but two of three nodes (including the node that went on to win the next election, term=5, first_boot=1) were fenced at the exact moment persist_recover ran. This matches task 5.1's own documented residual-risk note (tasks.md Implementation Notes, task 5.1 entry): 'the position check is diagnostically tautological for THIS SPECIFIC call site today... this will change once task 6's live apply pump gives expectation and actual state a real chance to diverge across threads/time' -- that predicted future divergence has now materialized under a slow-boot + concurrent-live-traffic combination that only a scenario driving traffic this early/aggressively after cluster boot (the factstream scenario) exercises; existing soak scenarios (chaotic/sequential/force-snapshot) submit far fewer jobs, more slowly, and do not reliably land traffic inside a slow node's pre-recovery window. REFINED after further reproduction (10/10 runs total, across ASAN/release builds and job counts from 8 to 20): the trigger is specifically the RESTART/catch-up path, not the initial multi-node cold boot. A standalone control test (3 nodes, no kill, 20s settle before any traffic) submitted jobs and drove jstart/jfinish/jfail cleanly with zero APPLY_DIVERGENT -- confirming the race needs a node that was DOWN while the cluster kept moving (i.e. an actual failover), not merely a fast cold boot: the returning node's persist_recover()/cluster_init_phase2 vtask must complete while it is ALSO receiving a compressed catch-up replication burst covering everything it missed while down, and that burst's volume is inherent to 'kill mid-fact-stream' (the whole point of the scenario) -- a run-ha-soak.sh-side pacing fix cannot eliminate the trigger the way it did for the (separately real but distinct) initial-boot instance the settle-delay mitigation addresses. Reproduced identically down to 8 fact-stream jobs with 2-job/1s-gap waves, so the trigger threshold is low. This plausibly explains why no prior soak scenario in this spec's history (chaotic/sequential/force-snapshot, all using NJOBS=3 by default, un-paced but small) ever surfaced it: none combine a real kill-during-traffic failover with this much job+fact volume until raft-apply-decoupling task 7.2's factstream scenario. Also independently added test.c's print_jobinfo state_raw hex field (task 7.2) and confirmed via a live probe that apply_job_fail_transition correctly applies EXIT|PERR bits even when job_state_str's RUN-checked-first priority ordering hides them in the pretty-printed state string (job showed 'state: RUN' / 'state_raw: 0x106' after a jstart+jfail-without-jfinish sequence) -- a separate, minor, likely pre-existing (not introduced by raft-apply-decoupling) display-only quirk in job_state_str, also not fixed here (out of boundary), but which the factstream phantom-check was updated to work around by reading state_raw instead of the ambiguous pretty string.
## Fix
FIXED (round 2, raft-apply-decoupling task 7.2 review remediation). Root cause confirmed exactly as hypothesized in the prior entry's candidate #2: persist_verify_apply_correctness() compared a WAL-scan-derived 'expected' snapshot against a LIVE re-read of last_applied_lsn/count_jobmgr_entries(), while TWO live mutation paths could write those same values concurrently -- the live apply pump (persist_apply_pump_run, driven by persist_apply_pump_kick off any of commit.c's 6 committed_lsn-advance sites) and the standby live-replication apply path (ha_apply_single_entry / ha_apply_term_entry_via_library in ha.c). Fixed via a new _Atomic bool persist_t.recovery_complete gate (persist.h/persist.c): persist_apply_pump_kick() now no-ops while the gate is closed; ha_apply_single_entry/ha_apply_term_entry_via_library now skip ONLY the in-memory apply_wal_entry() call while closed (durability write + replication ACK + applied_lsn advance are never gated, preserving the existing persist-before-apply-before-ACK contract and bug-1043's durability/materialization decoupling precedent). persist_recover() closes the gate at entry and reopens it (plus issues one deliberate persist_apply_pump_kick catch-up pass) right before returning, regardless of verdict -- covering any direct unit-test caller. ROUND 2 FINDING during live verification: this alone was insufficient -- a node stuck retrying its own election as a losing/timing-out candidate can receive and durably apply live-replicated entries via the ungated (persist_init default=true) path for tens of seconds BEFORE cluster_init_phase2() ever calls persist_recover() for the first time, reproducing the identical false-DIVERGENT symptom via an earlier entry point that persist_recover()'s own bracket cannot see. Closed by adding persist_mark_recovery_pending(&c.persist) in myapp_run() (myapp.c), called immediately after persist_init()/persist_start() succeed and BEFORE ha_start_election_async()/cluster_run() can process any network traffic -- closing the gate from the earliest safe moment in the real boot sequence. persist_init()'s default stays TRUE (ungated) so none of this spec's ~20 existing unit-test fixtures that construct a persist_t directly (bypassing myapp_run entirely) are affected; persist_mark_recovery_pending is never called outside myapp.c. Verified: live 3-node factstream soak (2 rounds, kill+restart both rounds) now PASSes clean with zero APPLY_DIVERGENT/UNRECOVERABLE across 5 persist_recover() calls (2 initial-boot delayed by the SAME pre-existing election-instability condition that originally exposed the round-2 gap, 2 post-kill restarts, all APPLY_CLEAN); broader controller_unit_test sweep (23 groups incl. test_apply_correctness_verification's 3 real-divergence tests, test_apply_pump/_integration, test_ha_core_safety, test_demotion_convergence) shows zero new failures (only the 2 pre-existing, documented task-6.1/6.2 test_commit_barrier_reply.c failures remain, task 7.3's job). Real-divergence detection independently re-confirmed intact (test_apply_divergent_decision_forces_unconditional_fence, test_apply_divergent_loud_fence_sets_sticky_flag_and_stays_alive, test_real_replay_divergence_sets_unrecoverable_fence all still PASS).
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-1409, bug-1415