myxce/.wolf/bugs/bug-1772.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

41 lines
5.4 KiB
Markdown

---
id: "bug-1772"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "scheduler"
severity: "crash"
timestamp: "2026-09-05T00:00:00Z"
last_seen: "2026-09-23T10:05:00Z"
occurrences: 1
files: []
tags: ["scheduler", "snapshot-restore", "resreq-fingerprint", "cache", "pre-existing", "schedobj-duplication", "severity-medium", "tdd", "audit-reopened"]
related: ["bug-1767", "bug-1770"]
legacy: true
gitea_issue: 52
gitea_synced_status: "fixed"
---
# bug-1772: out-of-scope gap discovered during requirements scoping for the resreq-maxtasks-wiring spec…
## Description
OPEN, NOT A CRASH -- pre-existing, out-of-scope gap discovered during requirements scoping for the resreq-maxtasks-wiring spec (bug-1770's fix). snapshot_build_primary_schedobj() (src/scheduler/src/snapshot_load.c:81-96) never computes primary->resreq_fp at all, unlike core_build_primary_schedobj() (src/scheduler/src/core_events.c:130-135), which sets resreq_fp.min_tasks/max_tasks/select_node_id/rusage_hash from the parsed xce_primary_resreq_t immediately after parsing. Every job reconstructed from a snapshot (post-restart or post-failover restore) therefore gets a zeroed resreq_fp -- the same class of gap as bug-1767's broader 'recurring schedobj-reconstruction-duplication' pattern (snapshot_load.c independently re-implements core_events.c's schedobj construction rather than sharing it, and each independent copy has repeatedly drifted field-by-field). TRIGGER CORRECTION (2026-09-05, resreq-maxtasks-wiring design review): this entry's original phrasing ('post-restart or post-failover restore') overstates the live trigger. xce_sched_core_load_snapshot()'s ONLY real (non-test) caller anywhere in src/ is sim.c's sim_locate_and_load_snapshot(), reachable only via main.c's --sim FILE offline replay flag. Normal-mode main.c has no snapshot-load call or flag at all; a live scheduler restart (including post-failover, e.g. run-ha-soak.sh's restart_scheduler_for_new_primary()) starts with empty in-memory state and rejoins via on_scheduler_join() -> the same core_build_job() path fresh ingest uses -- never touching snapshot_load.c. The accurate trigger is: a job in a .replay-recorded snapshot loaded by the --sim simulation/replay driver, not any live-cluster crash-recovery or failover scenario. This does not change the bug's validity or fix (the gap is real for --sim/replay fidelity, which matters per this project's driver-equivalence invariant since --sim drives the identical allocator dispatch) -- it only corrects when it's actually reachable, which matters for scoping test coverage (an HA soak does NOT exercise this path at all).
## Environment
_Not recorded (migrated from buglog.json)._
## Reproduction
_Not recorded (migrated from buglog.json)._
## Root cause
snapshot_load.c's snapshot_build_primary_schedobj() is a hand-duplicated, field-for-field port of core_events.c's core_build_primary_schedobj() (kept independent because core_build_primary_schedobj() is static and the two files are compiled as separate objects -- see bug-1767's own root-cause text for the deliberate-duplication rationale). The port was written before task 1.2 (scheduler-allocation feature) added resreq_fp/hash_rusages() wiring to the core_events.c original, and the snapshot_load.c copy was never updated to match. Effect: a snapshot-restored job's unsatisfiable-resreq cache fingerprint (used by scheduler-allocation's alloc_cache.c) is always the zero value, which is a valid-looking but WRONG fingerprint -- it could produce a false cache hit against an unrelated job that also happens to have a zeroed fingerprint (extremely unlikely today since real jobs always populate resreq_fp correctly at first ingest, but a snapshot-restored job's own fingerprint stays wrong for its entire post-restore lifetime, and any code that later relies on comparing/keying by resreq_fp for a restored job silently gets 0/0/0/0). Discovered while scoping resreq-maxtasks-wiring (bug-1770's fix spec) because that fix will make resreq_fp carry real, meaningful, non-degenerate maxTasks values for the first time -- increasing the practical consequence of this gap versus its current all-zero-everywhere baseline.
## Fix
FIXED (2026-09-23, TDD, /xce-audit-invariants scheduler dimension-4 audit -- independently re-found by both a dedicated subagent and direct investigation into bug-1845; this entry's own prior 'fixed'/'closed-by-scheduler-sim-live-allocation' tags were STALE/WRONG -- direct code inspection confirmed snapshot_build_primary_schedobj() still had no resreq_fp computation immediately before this fix). Added the same four-field resreq_fp computation core_build_primary_schedobj() (core_events.c) performs -- min_tasks/max_tasks/select_node_id/rusage_hash -- to snapshot_build_primary_schedobj() (snapshot_load.c), matching that function's own documented 'field-for-field port' contract, which had simply never included this field. Added test_snapshot_load_computes_resreq_fingerprint_for_restored_primary() (test_snapshot_save_load.c) -- a job restored from a snapshot with mintasks=4/maxtasks=6 must have schedobj->u.primary->resreq_fp.min_tasks/max_tasks reflect those real values, not {0,0,0,0}. Verified genuine red->green: temporarily reverted just the new resreq_fp assignment and reran -- scheduler snapshot save load test FAILED (exit 1); restored the fix and reran -- full 85/85 scheduler suite green.
## Verification
_Not recorded (migrated from buglog.json)._
## References
- Related: bug-1767, bug-1770
- Gitea: #52