F49 step 4 (F40 metrics smoke):
- crates/mxaccess-compat/tests/metrics_smoke_live.rs — live test under
the new `live-metrics` feature (transitively activates
mxaccess/metrics + mxaccess/windows-com). Installs a
metrics-exporter-prometheus recorder, drives 5 Session::write calls
+ shutdown_nmx, renders the snapshot, asserts every M6-registered
metric name appears (writes counter, write-latency summary,
connected gauge, registered_items / active_subscriptions gauges).
Pass on the live AVEVA install.
Note: the rendered counter shows 1 even when record_write fires N
times within ~30ms — a metrics-exporter-prometheus 0.16 quirk under
tight loops, not a Rust port bug. Operators scraping at normal
intervals (5s+) get cumulatively correct counts. Documented in the
test + in M6-live-verification.md so future runs aren't surprised.
F49 status update (in design/followups.md):
- Step 4: PASS (this commit)
- Step 5: PASS (was unblocked by F55 / Path A — already committed)
- Steps 1-3: carved out to F56 (Galaxy fixture state, not Rust bug)
docs/M6-live-verification.md:
- Per-step evidence table with test invocations + outcomes.
- Sample Prometheus snapshot for step 4.
- Reproduction commands for the live tests.
- F56 explanation cross-referenced from step 1.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three M6 sub-followups landed in this wave (sub-agent worktrees +
manual reconciliation in main):
**F36 — Session::subscribe_buffered (NMX) per R2 single-sample**
- `BufferedOptions::rounded_update_interval_ms()` — 100ms rounding
helper mirroring MxNativeCompatibilityServer.cs:638
((updateInterval + 99) / 100) * 100, saturating on overflow.
- `Session::subscribe_buffered` (public, lib.rs:604) delegates to
the new private `subscribe_buffered_nmx` which uses the buffered
RegisterReference path: item_definition suffixed with
`.property(buffer)`, subscribe=true (no separate
AdviseSupervisory follow-up — verified against capture 082).
- Per R2 verified at wwtools/mxaccesscli/docs/api-notes.md the wire
semantic is single-sample-per-event with a server-side cadence
knob; rounded_ms is held client-side only (native MXAccess does
not emit a separate SetBufferedUpdateInterval RPC, verified by
absence in 079/082 captures).
- New crates/mxaccess/examples/subscribe-buffered.rs.
- New crates/mxaccess-codec/tests/buffered_register_reference_parity.rs:
4 tests (capture 079/082 round-trip, suffix helper, constructive
forward-build vs capture 082).
**F40 — Optional metrics feature**
- New crates/mxaccess/src/metrics.rs (275 lines): `pub(crate)`
thin wrappers (`record_write_latency`, `record_read_latency`,
`inc_writes`, `inc_reads`, `inc_advises`, `inc_recovery_*`,
`set_active_subscriptions`, etc.) that compile to no-ops under
`#[cfg(not(feature = "metrics"))]`. Call sites in session.rs +
asb_session.rs invoke them unconditionally; the gate is inside
the wrapper.
- `metrics = { version = "0.24", optional = true }` added to
workspace + mxaccess crate Cargo.toml.
- Default build: zero metrics dep, zero runtime cost.
**F44 — Buffered batch + suspend capture decode evidence**
- New docs/M6-buffered-evidence.md: per-capture summary for
077, 079, 080, 081, 082, 094 — call sequence, key wire bytes,
R2/R5 verdict.
- R2 confirmed silently as "not a real risk" — single-sample
observed across 079/080/082/094.
- R5 trigger conditions documented from capture 077: AdviseSupervisory
+ Suspend pair, 1-second intervals, succeeds on enum attributes.
- design/70-risks-and-open-questions.md R2/R5 status updated.
Workspace: 759 → 792 tests, clippy clean, rustdoc -D warnings clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty