# Sylpheed regression goldens

These JSON files anchor `xenia-rs check` digest output for Project Sylpheed.

## Files

| File | -n | Mode | Captures |
|------|----|------|----------|
| `sylpheed_n2m.json` | 2_000_000 | full digest | early boot (swaps=0, no rendering) |
| `sylpheed_n50m.json` | 50_000_000 | stable-digest | first VdSwap pair (swaps=2 post-Phase-A) |

## Stable-digest mode

`sylpheed_n50m.json` is captured with `--stable-digest`, which omits
timing-sensitive counters: `packets` (±2–8% lockstep noise from a GPU thread
race), `resolves`, `interrupts_delivered`, `interrupts_dropped`,
`texture_decodes`. The remaining fields are byte-identical across repeated
lockstep runs at a fixed -n.

`sylpheed_n2m.json` predates the stable-digest flag and uses full-digest
compare. It still works because at -n 2M the GPU pipeline has not produced any
packets yet — `packets=0` is trivially deterministic.

## Circularity hazard

Per ORACBUG-001/002/003, these goldens were captured by running the same code
they validate. They detect **regression** from a known-good snapshot, not
**correctness**. When a planned fix intentionally moves the digest (e.g. a
shader fix landing `draws > 0` for the first time), re-baseline the golden as
a separate commit and reference the audit ID in the message.

## Re-baselining

```sh
cargo build --release -p xenia-app
target/release/xenia-rs check \
    "$SYLPHEED_ISO" \
    -n 50000000 \
    --stable-digest \
    --out crates/xenia-app/tests/golden/sylpheed_n50m.json
```

## Running the goldens

```sh
cargo test --release -p xenia-app --test sylpheed_oracles -- --ignored --nocapture
```

The tests are `#[ignore]`-gated because each run takes a few seconds, which is
unacceptable in the default `cargo test` cycle. The ISO path defaults to the
contributor's local `~/RE Project Sylpheed/Project Sylpheed*.iso` and can be
overridden via `SYLPHEED_ISO=/path/to/sylpheed.iso`.

## n4b canonical-invocation regression anchor (deferred)

The audit's recommended next sprint also called for a `sylpheed_n4b.json`
golden capturing the canonical reference invocation
`xenia-rs check sylpheed.iso -n 4_000_000_000 --parallel --reservations-table`.
This is **deferred** because:

1. The `--parallel --reservations-table` combination is empirically pathologically
   slow at -n 100M (>32 min per run per the audit memory). At -n 4B the run cost
   is many hours, not the single-session-friendly 5–15 min the original plan
   estimated.
2. Each phase that intentionally moves rendering counters (C, D, E, F) would
   need a re-baseline of n4b — a significant time cost compounding over the
   sprint.

Once the renderer-unblock phases (C+D+E) land and `draws > 0` is confirmed at
-n 100M lockstep, an n4b artifact may be captured one-shot and stored under
`audit-runs/post-fix/` (not as a test golden) as a manual regression anchor for
the canonical invocation.