xenia-rs/audit-runs/phase-c12-NtQueryFullAttributesFile/re-validation.md

# Phase C+12 re-validation (cold-vs-cold)

## Cache-wipe protocol (CORRECTED from C+11.1)

The Phase C+11.1 protocol wiped `~/.local/share/Xenia/cache`, but
the Windows-debug canary running under wine actually stores its
cache at `xenia-canary/build-cross/bin/Windows/Debug/cache/` (the
binary directory; verified by canary's `Storage root: Z:\...\build-
cross\bin\Windows\Debug` startup log). C+12's effective wipe targets
the binary directory.

Step-by-step (the protocol used here):

1. Backup canary's binary-dir cache:
   `tar -czf /tmp/canary-binary-cache-backup.tar.gz -C
    xenia-canary/build-cross/bin/Windows/Debug cache`
   (4.7 MB, 23 files). Copy to
   `audit-runs/phase-c12-NtQueryFullAttributesFile/
    canary-binary-cache-pre-wipe.tar.gz`.
2. Wipe both engines' caches:
   * `find xenia-canary/build-cross/bin/Windows/Debug/cache -mindepth 1 -delete`
   * `find xenia-canary/build-cross/bin/Windows/Debug/cache0 -mindepth 1 -delete`
   * `find xenia-canary/build-cross/bin/Windows/Debug/cache1 -mindepth 1 -delete`
   * `find ~/.local/share/xenia-rs/cache -mindepth 1 -delete`
3. Cold ours run:
   `./xenia-rs/target/release/xrs-c12 exec --phase-a-event-log
    /tmp/ours-cold-c12-v2.jsonl -n 50000000 "<ISO>"`
   (~3 s wallclock).
4. Cold canary run (background, killed after 5M+ canary events):
   `cd xenia-canary/build-cross/bin/Windows/Debug &&
    /usr/bin/wine ./xc-c12.exe --mute=true
    --phase_a_event_log_path=canary-cold-c12-v2.jsonl "<ISO>"`
   Killed via `wineserver -k` after ~120 s wallclock once the jsonl
   reached ~6 M lines (250 k tid=6 events buffered).
5. Truncate canary jsonl per-tid (cap tid=6 at 250 k, other tids at
   20 k) to keep the diff tractable. Truncated file is 119 MB / 533 k
   lines (kept) — the differ runs on this.
6. Diff:
   `python3 xenia-rs/tools/diff-events/diff_events.py
    --canary <truncated> --ours /tmp/ours-cold-c12-v2.jsonl
    --out /tmp/diff-c12-cold-v2.md`.
7. Restore canary's binary-dir cache from backup so future runs
   keep the oracle intact.

## Canonical post-C+12 cold-vs-cold matched-prefix table

| canary_tid | ours_tid | matched | canary_total | ours_total | first_divergence_at | notes |
|---|---|---|---|---|---|---|
| 6  | 1  | **103862** | 250000 | 108471 | 103862 | **main chain — +1458 events vs C+11.1**. New divergence: NtCreateFile `game:\dat\files.tbl` returns canary=STATUS_OBJECT_NAME_NOT_FOUND (0xC0000034) / ours=STATUS_SUCCESS (synth-empty stub for missing disc files; AUDIT-006 fallback). |
| 4  | 11 | 9          | 20000  | 9      | —      | sister — no divergence within the 9 ours events |
| 7  | 2  | 29         | 29     | 30     | —      | sister — no divergence within the 29 canary events |
| 12 | 7  | 2          | 10532  | 3      | 2      | sister — pre-existing KeWaitForSingleObject return (TIMEOUT/SUCCESS); NOT regressed |
| 14 | 9  | 39         | 20000  | 75     | 39     | sister — pre-existing XAudio init divergence; NOT regressed |
| 15 | 10 | 15         | 20000  | 15     | —      | sister — no divergence within the 15 ours events |

## Gate matrix

| gate | result | notes |
|---|---|---|
| Build (cargo build --release) | PASS | 1 unrelated `dead_code` warning, no errors |
| Kernel tests (172 → 177) | PASS | 5 new C+12 tests, all pass |
| Full workspace tests | PASS | 702 tests pass (sum of all crates) |
| Determinism — 3× cold stable-digest | PASS | `ad4f74ee324fdedb0bfdd4cc4c6468e9` (all 3) — IDENTICAL to C+11.1 baseline |
| `--stable-digest` digest unchanged | PASS | C+12 fix is observation-only on the stable counters |
| Phase B `image_loaded_sha256` | PASS | `ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18` unchanged |
| Cold-vs-cold matched prefix | PASS | **102404 → 103862 (+1458)** on main chain |
| Sister-chain regression check | PASS | All 5 sister chains unchanged |

## Source data

| file | size | notes |
|---|---|---|
| `canary-cold.jsonl` | 1.4 GB | full canary cold run, 6.0 M lines (post-kill) |
| `canary-cold-tid6-250k.jsonl` | 119 MB | per-tid truncated for diff (tid 6: 250 k, others: 20 k cap) |
| `ours-cold.jsonl` | 28 MB | ours cold run, 121 k tid=1 events |
| `diff-cold-vs-cold.md` | 8 KB | the `diff_events.py` output |
| `canary-binary-cache-pre-wipe.tar.gz` | 4.7 MB | canary's 23-file oracle preserved before wipe (binary-dir!) |
| `digest-cold-stable-{1,2,3}.json` | <1 KB each | 3 determinism runs, identical hash |
| `phase-b-snap/ours/` | ~5 MB | Phase B 5-file snapshot with `image_loaded_sha256` |

## Notes

* The +1458-event advance lands at a new tid=6 divergence:
  `NtCreateFile game:\dat\files.tbl` returns SUCCESS in ours because
  the disc dump doesn't ship this file but ours's `open_vfs_file`
  fallback synthesizes a 0-byte file (see `exports.rs:1399-1422`),
  while canary returns `STATUS_OBJECT_NAME_NOT_FOUND` since it has
  no equivalent stub. This is a long-standing intentional fallback
  (rationale: "synthesize empty file lets the game's existence
  probe succeed for files the rip lacks") that now becomes the
  next divergence target.
* The synth-empty fallback was originally introduced to prevent
  `XamShowDirtyDiscErrorUI` on missing disc files — removing it
  outright might regress past audits. Phase C+13 should investigate
  whether Sylpheed actually needs the file or whether the dirty-disc
  path is now correctly gated by other logic.
* Stable digest unchanged confirms the C+12 fix is a **pure observation
  change**: the in-memory entry tree and the `nt_query_full_attributes_
  file` rewrite affect only the kernel's response on `cache:` lookup
  probes, not the per-instruction execution path observed by the
  digest. The 1458-event advance is the kernel-export-side effect.