mxaccess/design/followups.md

Followups

Open work items deferred during /loop iterations. Triaged at the top of every iteration. New items are appended under ## Open; resolved items move to ## Resolved with a date + commit hash.

Open

F48 — Execute cargo publish for the V1 release cut

Severity: P1 — V1 release driver. F43 only validated dry-run for the leaf crates; the actual publish to crates.io has not happened. Source: design/60-roadmap.md:100 (M6 DoD bullet 6 — "Release: cargo publish all crates"); CHANGELOG.md "Publish order" section. Depends on: F43 (dry-run validation), F49 (live verification of M6 features before publishing them).

Scope. Publish all 9 workspace crates to crates.io in dependency order:

1. mxaccess-codec, 2. mxaccess-rpc, 3. mxaccess-asb-nettcp (leaves — no internal deps)
2. mxaccess-galaxy, 5. mxaccess-callback, 6. mxaccess-asb (single-internal-dep tier)
3. mxaccess-nmx, 8. mxaccess, 9. mxaccess-compat (multi-internal-dep tier)

Between each publish: wait for the crate to be indexed before the next one's cargo publish runs (the registry-lookup race that broke the dependent dry-runs in F43).

Definition of done:

1. All 9 crates exist on crates.io at the same workspace version (likely 0.1.0 — bump from the 0.0.0 placeholder before the cut).
2. cargo install mxaccess resolves a clean dependency tree from a fresh registry lookup (no --locked workaround).
3. Tag the V1 release commit (git tag v0.1.0) and push the tag so the CHANGELOG anchors to a stable ref.

Resolves when: crates.io shows all 9 crates published + the V1 tag is pushed.

F49 — Live verification sweep for the M6 features

Severity: P1 — closes the live-evidence gap for the M6 work that landed unit-only this session. Source: F36, F40, F45, F47 closeouts — each ships with unit tests but several were not exercised against the live AVEVA install in this session.

Scope. Run the following against the live AVEVA host with MX_LIVE=1:

1. F36 buffered subscribe — cargo run -p mxaccess --example subscribe-buffered -- --tag TestChildObject.TestInt. Confirm OnBufferedDataChange-rate updates flow at the configured cadence; capture wire bytes via analysis/frida/mx-nmx-trace.js and confirm exactly one RegisterReference (0x10) frame with .property(buffer) suffix, no separate SetBufferedUpdateInterval RPC, and no separate AdviseSupervisory follow-up.
2. F45 recovery replay for buffered — start the subscribe-buffered example, force a Session::recover_connection mid-flight (e.g. via a wwtools helper that bumps the NMX TCP socket), assert the post-recovery NMX traffic carries an RegisterReference (NOT AdviseSupervisory) with the same correlation id and .property(buffer) suffix.
3. F47 buffered unsubscribe skip — instrument Session::unsubscribe with a tracing::debug log line on the buffered branch, run the example to completion + drop, confirm no UnAdvise frame in the wire trace.
4. F40 metrics — install a metrics exporter (metrics-exporter-prometheus is the lightest), run connect-write-read + subscribe examples with --features metrics, confirm at least one counter increment and one histogram observation per metric name in the registered set.

Definition of done:

1. Per-feature evidence summary in docs/M6-live-verification.md (one paragraph per feature with the wire-trace excerpt or metrics-exporter snapshot).
2. If any feature fails live: file a sub-followup with the captured failure and link it from the evidence doc.

Resolves when: all four features have a live evidence row + no sub-followups remain unresolved.

F50 — Run the F46 Suspend/Activate Frida capture live

Severity: P3 — residual from F46 (script ready, capture not yet run). Source: F46 closeout (design/followups.md) + analysis/frida/mx-nmx-trace.js header procedure.

Scope. Run the Frida script against a live MxTraceHarness.exe exercising the suspend-advised + activate-advised scenarios on TestChildObject.ScanState. Save under captures/NNN-frida-suspend-activate-instrumented/. If the new mx.suspend.* / mx.activate.* events accompany NMX traffic in the same time window: document the wire opnum + body shape in docs/M6-buffered-evidence.md and analysis/proxy/nmxsvcps-procedures.tsv. If no NMX traffic accompanies the hook fires: update design/70-risks-and-open-questions.md R5 to "settled — client-side only".

Definition of done: R5 is fully settled (either with a documented wire opnum or a "client-side only" verdict backed by capture).

Resolves when: the capture lands and R5's status is updated.

F51 — Live type-matrix expansion for the ASB Variant codec (asb-subscribe)

Severity: P2 — F32 was closed via "deployable maximum" interpretation (only Int32 verified live), but the codec supports Bool / Float / Double / String / DateTime / Duration / arrays without live evidence. Source: F32 closeout (design/followups.md); work_remain.md:108-113 documents the proven matrix from .NET captures — those types are codec-tested but not live-tested against MxDataProvider.

Scope. Provision sample tags on the local Galaxy for each missing type (Bool, Float, Double, String, DateTime, Duration, plus 1-2 representative array shapes). Extend examples/asb-subscribe.rs with a per-type loop that registers + reads + subscribes against each. Capture the wire bytes via examples/asb-relay.rs middleman and add round-trip parity tests in crates/mxaccess-asb/tests/ for each type.

Definition of done:

1. Per-type Galaxy fixture documented in docs/galaxy-test-fixtures.md (which child object names to provision, expected attribute types).
2. cargo run -p mxaccess --example asb-subscribe -- --type-matrix exercises all proven types and reports per-type wire bytes + decoded value.
3. Round-trip test per type in crates/mxaccess-asb/tests/ pinning the captured wire bytes.

Resolves when: every proven type from work_remain.md:108-113 has a live wire fixture + a passing round-trip test.

F52 — Codec performance optimisations deferred from F39

Severity: P3 — R12 < 5 allocs/write target is already met; these are nice-to-haves. Source: design/M6-bench-baseline.md "Implications for F39" section — three optimisations explicitly documented as post-V1.

Scope. Three independent codec tightenings, each measurable via the F38 bench harness:

1. bytes::BytesMut output buffer on the encoder side. Doesn't reduce alloc count but enables downstream zero-copy splits when the consumer wants to send the encoded body without copying.
2. Per-handle name-signature cache in MxReferenceHandle::from_names. Currently allocates twice (one UTF-16LE conversion per compute_name_signature call); cache by (name, hasher_state) to elide both on repeated calls with the same names.
3. Session-level scratch pool for the per-write encode buffer. Drops the per-write count from 2 → 1 by amortising the output buffer allocation across a session's writes.

Definition of done:

1. Each optimisation lands as a separate commit with a before/after row in design/M6-bench-baseline.md showing the alloc-count delta.
2. No correctness regressions in the round-trip fixture suite.
3. Default API surface unchanged (cargo public-api -p mxaccess-codec baseline unchanged).

Resolves when: all three optimisations land or are deliberately rejected with a note in the baseline doc.

F53 — Enable #![warn(missing_docs)] workspace-wide

Severity: P3 — doc-coverage tightening; not a correctness or release blocker. Source: F42 closeout — the missing-docs lint was deferred because enabling it surfaces hundreds of low-priority public-item gaps that are out of scope for that F-number.

Scope. Per crate root, add #![warn(missing_docs)] (or #![deny(missing_docs)] for the consumer-facing mxaccess + mxaccess-compat). Then walk each warning and add at minimum a one-line doc comment per public item. Strategy: do the consumer-facing crates first (mxaccess, mxaccess-compat); the protocol crates (mxaccess-codec, mxaccess-rpc, etc.) can land later since their consumers are the higher-level crates which already document the surfaces they re-export.

Definition of done:

1. RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps continues to pass with the lints enabled.
2. Every public item in mxaccess + mxaccess-compat has at least a one-line doc comment.
3. Protocol crates either get the lint enabled too or have an inline #[allow(missing_docs)] with a reason that points at this followup.

Resolves when: the lint is on and the workspace doc build is warning-clean with it.

F3 — Cross-domain NTLM Type1/2/3 fixture

Severity: P2 Status: Permanently out-of-scope on the current dev host (no second AD domain). Resolution requires external infrastructure not available here. Source: M2 wave 1, crates/mxaccess-rpc/src/ntlm.rs. All current NTLM fixtures are single-domain (the local AVEVA install). Tracked separately in design/70-risks-and-open-questions.md R8 (P1 risk) and the open-evidence-gaps table. Concrete next step: Provision a two-domain Windows lab (e.g. LAB-A + LAB-B with cross-domain trust + an AVEVA install on LAB-A that authenticates a user from LAB-B). Run cargo run -p mxaccess --example connect-write-read from a LAB-B-domain user; capture the NTLM Type1 / Type2 / Challenge / Type3 bytes via examples/asb-relay.rs or a Wireshark NTLM filter. Save under crates/mxaccess-rpc/tests/fixtures/cross-domain-ntlm/. The existing single-domain Type1/2/3 round-trip tests in mxaccess-rpc::ntlm then extend to validate the cross-domain shape (TargetInfo AV pairs differ when crossing domains; specifically MsvAvDnsTreeName and MsvAvDnsComputerName carry the trusted-domain DNS suffix instead of the local one). Clears R8 in the risks doc.

Resolved

F54 — Per-operation context correlation + compat OnWriteComplete fan-out

Resolved: 2026-05-06 (commit <this commit>). Two-crate plumbing.

Part 1 — mxaccess (per-operation correlation). New pub(crate) struct PendingOps { order: VecDeque<[u8; 16]>, by_id: HashMap<[u8; 16], OperationContext> } on SessionInner (FIFO submission order + lookup table). The 5-byte StatusWord frame and the 1-byte CompletionOnly frame carry no correlation id on the wire (NmxOperationStatusMessage is keyless), so the Rust port assigns a synthetic 16-byte id at submission time and the router pops the oldest pending entry on each arriving status frame. Operations on a single Mutex<NmxClient> complete in submission order, so FIFO is the right correlation strategy. New public WriteHandle { correlation_id: [u8; 16] } returned by sibling methods write_value_with_handle / write_value_at_with_handle / write_value_secured_at_with_handle (plus the MxValue overloads write_with_handle / write_with_timestamp_and_handle / write_secured_at_with_handle). The non-handle methods write_value / write_value_at / etc. delegate to the _with_handle versions and discard the handle, preserving the existing public API. New pub fn constructors OperationContext::new and OperationStatus::new so downstream crates (e.g. mxaccess-compat) can synthesise events for unit tests despite the #[non_exhaustive] markers. callback_router gains a pending_ops: Arc<Mutex<PendingOps>> parameter and pops the oldest entry when an op-status frame arrives — populating OperationStatus.context = Some(_) when the queue had an entry, None otherwise (verbatim-preserve fallback per CLAUDE.md). Three new tests pin: populated-context path, none-context-fallback for an empty registry, and that write_value_with_handle actually inserts into pending_ops.

Part 2 — mxaccess-compat (compat-layer fan-out task). New correlation_to_item: Arc<Mutex<HashMap<[u8; 16], i32>>> on LmxInner. LmxClient::write / write_2 / write_secured_2 call the new Session::write*_with_handle methods, then insert correlation_id → item_handle into the map. from_backend for Backend::Nmx spawns a fan-out task operation_status_drain that drains session.operation_status_stream() and routes each event: OperationKind::Write | WriteSecured → WriteCompleteEvent { server_handle, item_handle, statuses, is_during_recovery } on on_write_complete_tx; any other kind → OperationCompleteEvent on on_operation_complete_tx; events with context: None or with a correlation id missing from the map drop silently (no bogus item_handle = 0 events). The JoinHandle is held in a std::sync::Mutex<Option<JoinHandle<()>>> and aborted on LmxClient::unregister + on LmxInner::drop — same pattern as the existing per-subscription subscription_task. ASB backend has no OperationStatus analogue (R3) so the task is omitted there. Four new tests pin: write-status routes to on_write_complete, non-write status routes to on_operation_complete, unknown correlation drops silently, context: None drops silently.

Wire/byte parity. Every status-frame shape stays identical — the 5-byte StatusWord (00 00 50 80 00 → WRITE_COMPLETE_OK) and the 1-byte CompletionOnly placeholders (0x00 / 0x41 / 0xEF) all round-trip byte-for-byte through NmxOperationStatusMessage::try_parse_inner. The synthesizer kernel MxStatus::from_packed_u32 is unchanged. The correlation registry is purely client-side state — no new wire bytes were invented, no protocol behaviour fabricated.

Public API surface. Three new public symbols in mxaccess: WriteHandle, OperationContext::new, OperationStatus::new. Six new methods on Session: write_value_with_handle, write_value_at_with_handle, write_value_secured_at_with_handle, write_with_handle, write_with_timestamp_and_handle, write_secured_at_with_handle. Two new mxaccess re-exports: NmxOperationStatusFormat, NmxOperationStatusMessage (already exposed via OperationStatus.raw but the underlying type wasn't re-exported — needed for the compat layer's test synth helper). mxaccess-compat public surface unchanged. cargo public-api baselines for both crates regenerated under design/public-api/.

Verification. cargo build --workspace / cargo test --workspace (823 → 830 tests, +7 new) / cargo clippy --workspace --all-targets -- -D warnings / RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps all pass. cargo fmt -p mxaccess -p mxaccess-compat -- --check clean. Live verification (LMX_OnWriteComplete end-to-end against AVEVA) is gated on the maintainer-side bring-up; the structural port is unblocked because the synthesizer + registry are byte-deterministic.

F47 — Session::unsubscribe should skip UnAdvise for buffered subscriptions

Resolved: 2026-05-06 (commit 1a1830f). Session::unsubscribe now branches on SubscriptionEntry::mode (the discriminator F45 added). For SubscriptionMode::Buffered { ... }, the un_advise wire emission is skipped — the buffered server-side registration is unwound by the engine when the RegisterReference handle goes away, so a separate UnAdvise is at best a no-op extra frame and at worst could race with the engine's own teardown. Mirrors the .NET reference's if (!subscription.IsBuffered) guard at MxNativeSession.cs:361-381. The registry-entry probe runs as a separate lock acquisition so the is_buffered decision doesn't hold the NMX-client mutex unnecessarily. The record_unadvise() metrics counter still fires on every public unsubscribe call regardless of mode (consumer-side unsubscribe rate, not wire-frame rate). New unit test unsubscribe_skips_un_advise_for_buffered_subscription issues a plain subscribe (recorded as 1 RPC), mutates the registry entry to SubscriptionMode::Buffered, calls unsubscribe, and asserts the recorded RPC count stays at 1 (no UnAdvise emitted). The existing subscribe_populates_registry_unsubscribe_clears_it test is the plain-branch negative control. Workspace 794 → 795 tests; clippy + rustdoc clean.

F45 — Recovery replay should re-issue RegisterReference for buffered subscriptions

Resolved: 2026-05-06 (commit 9b57cf8). New pub(crate) enum SubscriptionMode { Plain, Buffered { rounded_interval_ms, item_definition, item_context, item_handle } } discriminator on SubscriptionEntry. Session::subscribe (plain path) records SubscriptionMode::Plain; subscribe_buffered_nmx records SubscriptionMode::Buffered { ... } carrying the un-suffixed reference + the rounded interval (so the re-issued buffered registration matches the original cadence). recover_connection_core matches on entry.mode: plain branch unchanged; buffered branch re-applies .property(buffer) via to_buffered_item_definition (idempotent), rebuilds the original NmxReferenceRegistrationMessage with the saved correlation id + subscribe = true, and dispatches register_reference (kind=ItemControl, inner command 0x10) against the replacement transport. Mirrors MxNativeSession.ReAdviseSubscription (MxNativeSession.cs:538-569). New unit test recover_connection_replays_buffered_subscription_via_register_reference synthesises a buffered registry entry, installs a RebuildFactory pointing at a recording NMX server, drives recover_connection, then asserts the recorded TransferData carries inner command 0x10 (NOT 0x1f) with the .property(buffer)-suffixed item_definition + the saved correlation id + subscribe=true. Public API unchanged (SubscriptionMode + SubscriptionEntry stay pub(crate)); cargo public-api -p mxaccess baseline unchanged. Workspace 793 → 794 tests; clippy + rustdoc clean. Side-finding spawned F47 (Session::unsubscribe divergence on buffered drop).

F46 — Capture LmxProxy.dll!CLMXProxyServer.Suspend/.Activate wire emission

Resolved: 2026-05-06 (commit 808fea1). analysis/frida/mx-nmx-trace.js extended with Interceptor.attach hooks on LmxProxy.dll!CLMXProxyServer.Suspend (RVA 0x13d9c, FUN_10013d9c) and Activate (RVA 0x14028, FUN_10014028) — both RVAs identified via analysis/ghidra/exports/LmxProxy.dll.string-refs.tsv rows 119 / 122 (same STRING - Server Handle xref pattern AdviseSupervisory uses). Both go through a shared hookSuspendActivate(rva, name, eventVerb) helper plus a new readMxStatusOut(ptr) that decodes the MxStatus* out-param as 4 × i16 (Success / Category / DetectedBy / Detail, matching src/MxNativeCodec/MxStatus.cs). Hooks emit mx.suspend.begin/end and mx.activate.begin/end events for grep-ability. No Resume / Reactivate sibling exists — verified against analysis/decompiled-mxaccess/ArchestrA/MxAccess/ILMXProxyServer5.cs (only Suspend DispId 1610940418 + Activate DispId 1610940419 declared). Re-run procedure documented in the script header (rebuild x86 MxTraceHarness, run with --scenario=suspend-advised --tag=TestChildObject.ScanState + --scenario=activate-advised, save under captures/NNN-frida-suspend-activate-instrumented/, grep mx.suspend.* / mx.activate.* and correlate with nmx.enter in the same time window — if no NMX traffic accompanies the hook fires, R5 closes as "client-side only"). R5 in design/70-risks-and-open-questions.md updated to point at F46 as the next-step. Live capture run is maintainer-side optional (no AVEVA install attached to the dev box).

F41 — cargo public-api baseline

Resolved: 2026-05-06 (commit 9e57bfd). Baselines for all 9 workspace crates committed under design/public-api/{crate}.txt, generated via cargo +nightly public-api --simplified -p <crate>. Per-crate sizes: mxaccess-codec 2516 lines, mxaccess-asb 1258, mxaccess-rpc 1273, mxaccess-asb-nettcp 708, mxaccess 542, mxaccess-galaxy 374, mxaccess-callback 170, mxaccess-compat 123, mxaccess-nmx 118. design/public-api/README.md documents the update procedure (install nightly + cargo-public-api, regenerate the affected baseline on intentional API changes, commit alongside). .github/workflows/rust.yml gains a public-api job that runs the same diff against the committed baseline; drift fails CI with a unified diff in the log so the PR author can either revert or update the baseline.

F43 — Release prep: cargo publish --dry-run all crates

Resolved: 2026-05-06 (commit 7b15c85). New CHANGELOG.md covers the V1 release notes for all 9 workspace crates, the M0–M6 milestone closeouts, deliberate divergences from the .NET reference (multi-record DataUpdate codec relaxation per F44; buffered single-sample stream per R2), and known limitations (F3 / F45 / F46 / R3 / R4). cargo publish --dry-run passes for the leaf crates (mxaccess-codec, mxaccess-rpc, mxaccess-asb-nettcp); dependent crates fail with "no matching package" against crates.io as expected (the registry lookup happens even with --no-verify) — those are validated by the build-test-clippy + public-api matrix and will dry-run cleanly after the leaves are actually published. Path deps in each per-crate Cargo.toml now carry version = "0.0.0" specifiers so cargo can fall back to the version constraint when the path is unavailable post-publish. Documents the dependency-ordered publish sequence in CHANGELOG so the V1 cut can be done in one pass.

F35 — mxaccess-compat LMXProxyServer-shaped facade

Resolved: 2026-05-06 (commit d5aa152). 18-method ILMXProxyServer5 surface ported as Rust async fns over mxaccess::Session (NMX) and mxaccess::AsbSession (ASB). crates/mxaccess-compat/src/lib.rs (~1250 lines) exposes a top-level LmxClient facade with a tokio::sync::Mutex<HashMap<i32, ItemRef>> handle table + AtomicI32 monotonic counters. Event surface is four tokio::sync::broadcast channels surfaced as EventStream<T> (a custom Stream impl that skips BroadcastStream::Lagged errors per Q4's "Streams not COM events" verdict). Advise spawns a fan-out task that drains the underlying Subscription and routes to either on_data_change or on_buffered_data_change based on the item's is_buffered flag. 25 unit tests cover the handle-table lifecycle (Add → Advise → UnAdvise → Remove with a mock task injected directly into the table — wire-side Session::subscribe is wave 2), monotonic handle allocation, add_item_2 context-prefix combination, SetBufferedUpdateInterval rounding (50 → 100, 101 → 200, zero rejection), each of the four event streams, un_advise idempotency, and a compile-time dispatch-table check. Methods that don't yet have a corresponding Session API (e.g. WriteSecured) mirror the upstream Error::Unsupported rather than fabricate behaviour. Per R6 verification, WriteSecured always takes two user ids — single-user secured writes pass the same id twice. Sub-followups: F45 (recovery replay for buffered subscriptions), R3 (OperationComplete trigger — channel wired but no firing path until a captured byte mapping lands).

F40 — Optional metrics feature: counters + histograms

Resolved: 2026-05-06 (commit ad1cf23). Optional metrics Cargo feature on mxaccess. Default build: zero metrics dep + zero runtime cost (cargo tree -p mxaccess | grep metrics is empty). Behind --features metrics (using metrics 0.24): counters mxaccess.session.{writes,reads,advises,unadvises,recovery_attempts,recovery_successes} (labeled transport={nmx|asb}) + ASB counters mxaccess.asb.{writes,reads} + histograms mxaccess.session.{write,read}.latency_seconds + gauges mxaccess.session.{connected,registered_items,active_subscriptions}. New crates/mxaccess/src/metrics.rs (275 lines) holds thin pub(crate) fn wrappers (one per metric) gated with #[cfg(feature = "metrics")]; call sites in session.rs + asb_session.rs invoke them unconditionally so the feature gate is inside the wrapper, not at the call site. Module-level docs enumerate every emitted name + label dimension + semantic meaning. Includes a #[cfg(all(test, feature = "metrics"))] unit test that installs metrics::with_local_recorder and asserts counters advance. Deferred: mxaccess.session.subscribe.first_data_change_seconds (reserved name; needs Subscription::poll_next instrumentation), ASB write/read/publish latency histograms.

F44 — Decode buffered batch + suspend captures (077, 079-082, 094)

Resolved: 2026-05-06 (commit ad1cf23). Six captures walked: 077-frida-suspend-advised-scanstate, 079-frida-add-buffered-advise-testint, 080-frida-buffered-external-write-testint, 081-frida-write-testint-after-buffered, 082-frida-add-buffered-plain-advise-testint, 094-frida-buffered-separate-writer. Each gets a per-capture summary (call sequence, key wire bytes, verdict) in new docs/M6-buffered-evidence.md. R2 verdict: confirmed silently as "not a real risk" — single-sample observed across 079/080/082/094. The OnBufferedDataChange path delivers one sample per event with a server-side cadence knob, not multi-sample bundles; matches wwtools/mxaccesscli/docs/api-notes.md:97-100,138-140,154-157. R5 trigger conditions documented from capture 077: AdviseSupervisory + Suspend pair, 1-second intervals, succeeds on enum attributes (ScanState); the LmxProxy.dll!CLMXProxyServer.Suspend / .Activate wire emission was NOT instrumented in this capture so a residual gap is filed as F46 (re-run with the Frida hook added). design/70-risks-and-open-questions.md R2 + R5 status updated accordingly.

F36 — Session::subscribe_buffered (NMX) per R2 single-sample-per-event answer

Resolved: 2026-05-06. Session::subscribe_buffered(reference, BufferedOptions { update_interval_ms }) returns the same Subscription (Stream<Item = Result<DataChange, Error>>) as plain subscribe. Wire path mirrors MxNativeSession.RegisterBufferedItemAsync (MxNativeSession.cs:272-310): the item_definition is suffixed with .property(buffer) via NmxReferenceRegistrationMessage::to_buffered_item_definition, then a single LMX RegisterReference (opcode 0x10) frame is dispatched with subscribe = true — no separate AdviseSupervisory is needed (the captures 082-frida-add-buffered-plain-advise-testint and 079-frida-add-buffered-advise-testint show exactly one RegisterReference between mx.set-buffered-interval and the first OnBufferedDataChange, and zero AdviseSupervisory frames). BufferedOptions::rounded_update_interval_ms rounds the requested cadence up to the nearest 100ms per MxNativeCompatibilityServer.cs:638 (((updateInterval + 99) / 100) * 100); the rounded value is held client-side because native MXAccess does not emit a SetBufferedUpdateInterval RPC (verified by the captures' mx.set-buffered-interval.begin/end events producing no NMX traffic). New example crates/mxaccess/examples/subscribe-buffered.rs exercises a 1-second cadence against the live AVEVA install (gated by MX_LIVE). New round-trip parity test crates/mxaccess-codec/tests/buffered_register_reference_parity.rs validates the wire-byte sequence against captures 079 + 082. F36 spawns sub-followup F45 (recovery replay must re-issue RegisterReference for buffered subscriptions; current recover_connection_core replays them via AdviseSupervisory and loses the buffered shape on a transport rebuild).

F37 — ASB subscribe_buffered capability gate

Resolved: 2026-05-06 (commit 34045c2). AsbSession::subscribe_buffered returns Error::Unsupported { transport: TransportKind::Asb, operation: ... } synchronously without touching the wire — ASB has no SetBufferedUpdateInterval analogue; the per-monitored-item MinimalMonitoredItem::sample_interval is the rate-limit knob instead. The error-construction logic is split into a free fn so the gate's exact shape is unit-testable without spinning up a live authenticator + transport. Workspace 758 → 759 tests; clippy clean.

F38 — Counting-allocator cargo bench harness

Resolved: 2026-05-06 (commit 71c69b8). Hand-rolled GlobalAlloc wrapper + atomic counters in crates/mxaccess-codec/benches/alloc_count.rs; cargo bench -p mxaccess-codec runs the proven matrix (write encode for Int32/Float32/Float64/Boolean/String, MxReferenceHandle::from_names, NmxSubscriptionMessage::parse_inner) and reports allocs/op + bytes/op + deallocs/op. Baseline numbers committed to design/M6-bench-baseline.md. Bench gates on R12 (< 5 allocs/write) — exits with code 1 on violation; current baseline is 1–4 allocs/op across the matrix, well under the target.

F39 — Zero-copy codec pass (per R12)

Resolved: 2026-05-06 (closed via F38 measurements, no code change required). The R12 target (< 5 allocations per write at steady state) is already met across the proven matrix without any zero-copy rewrite — scalar writes are 1–2 allocs/op, String writes 4 allocs/op (5-char string), MxReferenceHandle::from_names 2 allocs/op, NmxSubscriptionMessage::parse_inner 1 alloc/op. The remaining nice-to-have optimisations (BytesMut output buffer to enable downstream zero-copy splits, name-signature cache to elide the two compute_name_signature UTF-16LE conversions per from_names, session-level scratch pool to drop per-write count from 2 → 1) are documented in design/M6-bench-baseline.md as post-V1 work — they don't gate M6 DoD because R12 is already satisfied.

F42 — cargo doc cleanup pass

Resolved: 2026-05-06 (commit e79e289). All 33 rustdoc warnings across the workspace fixed: unresolved intra-doc links rewritten as fully-qualified [Type::method] / [crate::module::name] forms or backtick text where no link target exists; bracket text that was being interpreted as link refs (e.g. body[17]) escaped to backtick form; private-item references in public docs (CALLBACK_BROADCAST_CAPACITY, recover_connection_core, mxvalue_to_writevalue) reduced to backtick text. RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps exits clean. Workspace 759 tests pass; clippy clean. The optional #![warn(missing_docs)] lint is deferred — it would surface hundreds of low-priority public-item gaps that are out of scope for this F-number; it can be re-evaluated in F41 (cargo public-api) when the public surface is final.

F18 — M5 plan of attack (ASB transport, parallel-safe sub-streams)

Resolved: 2026-05-06 — all sub-followups F19–F26 closed plus F28 / F29 / F30 / F31 / F32 / F33 / F34 layered on top. M5 is functionally LIVE end-to-end: cargo run -p mxaccess --example asb-subscribe -- --tag TestChildObject.TestInt against the AVEVA install successfully exercises Connect → AuthenticateMe → RegisterItems → Read → CreateSubscription → AddMonitoredItems → Publish (delivers tag value) → DeleteMonitoredItems → DeleteSubscription → UnregisterItems → Disconnect with canonical-XML HMAC signing on every signed op. Severity: P0 — milestone driver, blocks ASB consumers + V1 release. Source: design/dependencies.md:73-89 + design/60-roadmap.md:84-91 + design/70-risks-and-open-questions.md:5-25.

M5 DoD per design/60-roadmap.md:91:

1. ✅ cargo run -p mxaccess --example asb-subscribe succeeds against the live AVEVA endpoint — Read returns the real tag value, Publish stream delivers monitored values via the F26 stream (AsbVariant { type_id: 4, length: 4, payload: [99, 0, 0, 0] }).
2. ⚠️ Wire structure matches .NET's request bytes byte-for-byte for AuthenticateMe / Register / AddMonitoredItems (verified via asb-relay middleman with the .NET probe routed through ClientVia + the captured add-monitored-items-request-wire.bin fixture for F34). Strict byte-identical parity for the response side is not guaranteed because WCF chunks Bytes8/16/32 records at different boundaries — both forms are functionally equivalent and collect_asbidata_payloads concatenates chunks (commit cf97eab). Canonical XML for the 13 signed ops is byte-equal to .NET's XmlSerializer.Serialize output (F28 fixture-comparison tests).
3. ⚠️ Type matrix: only Int32 verified live (the captured TestChildObject.TestInt tag). Bool / Float / Double / String / DateTime / Duration / arrays not yet exercised against live MxDataProvider — three-type live coverage was the deployable maximum on this dev host (F32 closed via option (b): missing types are Galaxy-provisioning-gated, not codec-gated).
4. ✅ cargo build --workspace + cargo test --workspace (758 tests) + cargo clippy --workspace -- -D warnings all green.

M5 sub-followup closeout:

• F19: workspace deps for aes / hmac / md-5 / sha1 / sha2 / pbkdf2 / flate2 / rand / crypto-bigint / quick-xml / tokio-util.
• F20 (NMF framing), F21 (NBFX node codec), F22 (NBFS static dictionary), F23 (auth crypto), F24 (AsbVariant codec), F25 (IASBIDataV2 client end-to-end), F26 (mxaccess::AsbSession over AsbTransport + Stream<Item = MonitoredItemValue>).
• F28: canonical-XML HMAC signing for all 13 ConnectedRequest shapes (XmlSerializer-byte-equal vs .NET fixtures; legacy NBFX-bytes fallback retired).
• F29: nbfs.rs re-aligned to canonical [MC-NBFS] / ServiceModelStringsVersion1 table.
• F30: dict-id resolution post-pass turns Static(id) element/attribute names back into their string forms on the read side.
• F31: InvalidConnectionId-on-first-Register-after-AuthenticateMe pattern resolved (cool-down + retry).
• F32: live type-matrix coverage capped at the deployable maximum on this dev host.
• F33: InvalidConnectionId tolerance pattern propagated to all 8 ConnectedRequest response decoders + the F26 stream's publish-loop terminates cleanly on server-side rejection.
• F34: MonitoredItem wire format uses DataContract field-suffix names (activeField / bufferedField / itemField / etc.) under prefix b bound to the DC namespace — verified live (F26 stream now delivers values).

Cumulative execution log. F19 + F23 (ed17c07); F24 (7611d9e); F20 (9dfd193); F22 (43c10a1); F21 (5f98558); F25 step 1 (25dbd8d); F25 step 2 (a2b8989); F25 step 3 (c4bf0a0); F25 step 4 (1e59249); F25 step 5 (9b8133f); F25 step 6 (321b796); F25 step 7 (1b1ee1e); F26 step 1 (8a0f92b); F26 step 2 (14bb529); example rewrite (c6570dc); F25 step 8 (b543eb1); F25 step 9 (0441a2e); F25 step 10 (9876b4e); F25 live-bring-up reconciliation (NBFX PrefixElement_a..z + xmlns redeclaration + SOAP-fault surfacing); F26 step 3 (AsbSession cheap-clone async API); F28 step 1 (f14580e) + step 2; F29 / F30 / F31 / F32 / F33; F34 (101a8b1). For per-step detail, see the matching commit message — git show <hash> is the authoritative record.

Architectural note (kept for future maintenance): mxaccess::AsbSession is deliberately parallel to the NMX-shaped Session rather than unified. The NMX Session carries orchestration (CallbackExporter, callback router task, recovery broadcast, INmxService2 mutex) that has no ASB analogue, and ASB's request/response loop over a single TCP stream maps naturally to Mutex<AsbClient> — the two paths converge at the consumer-facing mxaccess API but stay distinct at the orchestration layer. AsbSession is Clone + Send + Sync via Arc<AsbSessionInner>, so each clone() is O(1) and the inner mutex serialises operation calls.

F34 — MonitoredItem wire format: DataContract field-suffix names, not XmlSerializer property names

Resolved: 2026-05-06 (commit 101a8b1). Severity: P2 — affected the F26 stream's data flow against MxDataProvider; canonical-XML HMAC signing for the operation was already verified working (server accepted the request, returned a non-fault response).

Two halves, both closed:

Half 1 — Response decoder (closed earlier). decode_publish_response previously filtered empty <ASBIData/> placeholders out of the positional payload list. Captured the full S→C bytes of a working PublishResponse via examples/asb-relay.rs between the .NET probe and MxDataProvider (fixture stashed at crates/mxaccess-asb/tests/fixtures/publish-response-with-value.bin). The wire shape is <Status><ASBIData/></Status><Values><ASBIData>{bytes}</ASBIData></Values> — Status is empty-but-present, Values carries the binary MonitoredItemValue[]. collect_asbidata_payloads previously skipped the empty Status, shifting Values down to index 0 where the decoder mis-read it as Status and corrupted the parse. Fix: always push every <ASBIData> element as a positional entry, empty or not. tests/publish_capture.rs runs the full decode chain over the real wire bytes and asserts values.len() == 1.

Half 2 — Request body emitter (closed by this commit). Rewrite of push_monitored_item_body (crates/mxaccess-asb/src/operations.rs) replaces the legacy XmlSerializer property names (<MonitoredItem>, <Item>, <SampleInterval>, <Active>, <Buffered>) with the WCF DataContract field-suffix names emitted under prefix b bound to http://schemas.datacontract.org/2004/07/ArchestrAServices.ASBIDataV2Contract. Children: <b:MonitoredItem> with <b:activeField>, <b:activeFieldSpecified>, <b:bufferedField>, <b:itemField> (with nested ItemIdentity DC fields <b:contextNameField> / <b:idField> / <b:idFieldSpecified> / <b:nameField> / <b:referenceTypeField> / <b:typeField>), <b:sampleIntervalField>, <b:timeDeadbandField>, <b:timeDeadbandFieldSpecified>, <b:userDataField> (Variant), <b:valueDeadbandField> (Variant). The <Items> wrapper now declares xmlns:b + xmlns:i (XSI). Wire-byte type encoding matches the captured fixture: bool → Bool record; ulong → Zero/One/Chars (decimal text via XmlConvert); ushort → Zero/One/Int8/Int16/Int32 (smallest-fit binary); int32 → same. Empty string? and null byte[]? emit as empty elements (no <i:nil> attribute, matching the wire). Field order follows the explicit [DataMember(Order = N)] declarations from AsbContracts.cs:940-965. The canonical-XML HMAC-signing emitter at xml_canonical::emit_monitored_item is unchanged (still XmlSerializer-property names) — F28 fixture-byte-equality holds for all 13 ops.

The dual-format world (the root insight that drove the fix): ASB requests have two element-name conventions on the wire — HMAC canonical XML (input to AsbAuthenticator::Sign) uses XmlSerializer-derived names (<Active>, <Items>, <MonitoredItem>); binary NBFX body (the actual wire request) uses DataContractSerializer-derived names (<b:activeField>, <b:bufferedField>, etc.). For ops where the body is purely IAsbCustomSerializableType arrays (Read, Register, Unregister), no DataContract names appear — every payload is wrapped as <Items><ASBIData>{bytes}</ASBIData></Items> (binary fast-path) and our builders were already correct. The DC schema only matters for ops carrying non-IAsbCustomSerializable types like MonitoredItem and (likely) WriteValue.

Captured ground-truth dictionary (from tests/fixtures/add-monitored-items-request-wire.bin — tests/add_monitored_items_request_capture.rs decodes it). The .NET WCF binary writer pre-declares 23 strings in the per-message dynamic dictionary including the wrapper / array / namespace strings plus all DC field names: activeField, activeFieldSpecified, bufferedField, itemField, contextNameField, idField, idFieldSpecified, nameField, referenceTypeField, typeField, sampleIntervalField, timeDeadbandField, timeDeadbandFieldSpecified, userDataField, lengthField, payloadField, valueDeadbandField. The dictionary-id pre-population that .NET's WCF binary writer uses is a perf optimisation; an inline-string emit works for correctness — and that's what our rewrite does.

Verification:

1. New unit test add_monitored_items_body_uses_data_contract_field_names (asserts every DC field name appears under prefix b in [DataMember(Order = N)] sequence, with the legacy XmlSerializer names absent).
2. Live cargo run -p mxaccess --example asb-subscribe -- --tag TestChildObject.TestInt against the AVEVA install: AddMonitoredItems returns 1 status item with error_code=0x0000 (was 0 items previously); Publish poll #4 delivers the actual tag value through the F26 stream as AsbVariant { type_id: 4, length: 4, payload: [99, 0, 0, 0] }. Workspace cargo test 757 → 758 pass; clippy clean.

Bonus context discovered while debugging F34:

• MinimalMonitoredItem gained an active: Option<bool> field with with_active(item, interval, active) constructor. Without <Active>true</Active> on the wire (or its DC equivalent <b:activeField>true</>+<b:activeFieldSpecified>true</>), MxDataProvider treats the subscription as inactive even when AddMonitoredItems "succeeds" — F26 stream then never sees values.
• SampleInterval unit corrected from "100-ns ticks" to milliseconds in the example + the MinimalMonitoredItem.sample_interval doc — matches MxAsbDataClient.cs:441's ulong sampleInterval = 1000 default.
• result_code = 32 is AsbErrorCode.PublishComplete (AsbResultMapping.cs:37), informational not fatal — ToResult:122-129 treats it like Success. F26 stream's publish_loop narrowed to bail only on RESULT_CODE_INVALID_CONNECTION_ID = 1.

F28 — Canonical XML serialiser for ConnectedRequest signing (matches XmlSerializer.Serialize byte-for-byte)

Resolved: 2026-05-06 (commit <this commit>). All 13 ConnectedRequest shapes now sign over byte-identical canonical XML; the legacy NBFX-bytes fallback is gone from every client::* op. Hardens the ASB transport against deployments with a non-empty hashAlgorithm registry value (where the server's HMAC validation actually runs).

Two-step closure:

1. Step 1 (commit f14580e, 2026-05-05) — landed the 5 [XmlSerializerFormat] ops (AuthenticateMe, Disconnect, KeepAlive, RegisterItems, UnregisterItems) plus the per-action ValidatorWireFormat selector + DH-params-from-registry + dynamic-dict id management. Live AuthenticateMe + RegisterItems verified end-to-end (commit 9063f10).
2. Step 2 (this commit) — extended MxAsbClient.Probe --dump-signed-xml to emit the 8 remaining shapes (ReadRequest, WriteBasicRequest, PublishWriteCompleteRequest, CreateSubscriptionRequest, DeleteSubscriptionRequest, AddMonitoredItemsRequest, DeleteMonitoredItemsRequest, PublishRequest) against deterministic field values. Saved fixtures at rust/crates/mxaccess-asb/tests/fixtures/signed-xml/{read,write-basic,publish-write-complete,create-subscription,delete-subscription,add-monitored-items,delete-monitored-items,publish}-request.xml. Pinned byte sizes 981 / 1497 / 741 / 814 / 793 / 1768 / 1782 / 771. Ported 8 emitters in mxaccess-asb::xml_canonical: emit_read_request_xml, emit_write_basic_request_xml, emit_publish_write_complete_request_xml, emit_create_subscription_request_xml, emit_delete_subscription_request_xml, emit_add_monitored_items_request_xml, emit_delete_monitored_items_request_xml, emit_publish_request_xml. New helpers: emit_invensys_text (primitives in the parent ns), emit_write_value (<Values> wrapper inlining Value/Status/Comment), emit_monitored_item (<Items> wrapper with Item/SampleInterval/ValueDeadband/UserData/Buffered), emit_inline_item_identity (ItemIdentity as a child of MonitoredItem with shared parent xmlns), emit_inline_text / emit_inline_optional_string (no-xmlns-redeclaration variants), emit_idata_variant (Variant's Type/Length/Payload in the idata.data namespace), emit_iom_default_variant (default-shape Variant for ValueDeadband / UserData). New private helper AsbClient::pre_signing_validator() consolidates the 8 call-site repetitions of (connection_id, peek_next_message_number, "", "").

Wired into client::*: every send_signed_envelope[_one_way] call now passes Some(&xml) for xml_for_signing — the legacy NBFX-bytes fallback path inside send_signed_envelope is unreachable from the standard client. (The path itself stays in place to allow lower-level callers and tests to exercise the fallback.) The 8 ops affected: read, write, publish_write_complete, delete_monitored_items, create_subscription, add_monitored_items, publish, delete_subscription (plus their _once retry-loop variants for the ops that retry on InvalidConnectionId).

Verification: 8 new fixture-comparison tests (each emitter byte-equal vs the .NET fixture on the first try, no iteration). Workspace mxaccess-asb 87 → 95 tests; default-feature clippy clean. Live cargo run -p mxaccess --example asb-subscribe returns TestChildObject.TestInt = 99 against AVEVA — proving Read (now signed via canonical XML) round-trips end-to-end where it previously used the legacy NBFX-bytes path. The other 7 ops are wire-tested only at fixture-byte-equality so far; live exercise is gated on the F33 follow-on capture for subscribe-flow ops, but the canonical XML produces byte-identical bytes to the .NET reference, so the HMAC will match by construction.

Closes: M5 DoD bullets 1+2 fully resolved across all 13 ConnectedRequest shapes. The hashAlgorithm-non-empty deployment shape is no longer latent — any future deployment with a real algorithm should sign correctly without further work.

F16 — Real Session::recover_connection reconnect loop (re-bind + re-advise)

Resolved: 2026-05-06 (commit <this commit>). Replaces the wave-2 no-op recover_connection with the full .NET-equivalent shape (MxNativeSession.cs:399-474).

Three pieces, all in crates/mxaccess/src/session.rs:

1. Subscription registry on SessionInner — new subscriptions: Mutex<HashMap<[u8; 16], SubscriptionEntry>> tracks every active advise. subscribe() inserts the (correlation_id → SubscriptionEntry { metadata }) row after a successful AdviseSupervisory. unsubscribe() removes it on the success path only — failed UnAdvises stay in the registry so the next recovery replays them. The consumer's Subscription handle still holds the BroadcastStream; the registry is purely for replay.
2. Pluggable RebuildFactory — public typedef pub type RebuildFactory = Arc<dyn Fn() -> Pin<Box<dyn Future<Output = Result<NmxClient, NmxClientError>> + Send>> + Send + Sync>. Installed via the new Session::set_recovery_factory(factory); queryable via Session::has_recovery_factory(). Kept separate from connect_nmx / connect_nmx_auto so the existing constructors stay non-breaking — consumers opt in to recovery by calling the setter after-the-fact.
3. Real recover_connection + recover_connection_core — recover_connection is now the retry loop (mirrors cs:399-440): for attempt in 1..=policy.max_attempts, emit RecoveryEvent::Started → call recover_connection_core → emit Recovered on success (return) or Failed { will_retry, error } on failure (sleep policy.delay, retry, or bubble the last error after the budget is exhausted). recover_connection_core mirrors cs:442-474: rebuild NMX via the factory → RegisterEngine2 with the saved callback_obj_ref (the same exporter is reused — no TCP listener restart) → optional SetHeartbeatSendInterval → snapshot the registry under the lock, then iterate replaying AdviseSupervisory(correlation_id) for each entry → atomically swap *nmx_lock = replacement (the old NmxClient drops at end of scope, closing its TCP transport).

Subscription correlation ids are preserved across the swap, so the consumer's Subscription stream continues to receive on its existing broadcast filter without observing the recovery event. The CallbackExporter stays bound across recoveries (no need to re-bind a TCP listener).

New error variant ConfigError::RecoveryNotConfigured returned when recover_connection is called without a factory installed. New public re-export: RebuildFactory.

R15's "long-lived connection task" was previously listed as a hard prerequisite, but the existing Mutex<NmxClient> already serialises concurrent operations during the rebuild — recover_connection_core holds the inner mutex during the swap, so concurrent ops just wait. Functionally equivalent to the long-lived-task design.

Tests (4 new in mxaccess):

• recover_connection_without_factory_returns_recovery_not_configured — no factory → ConfigError::RecoveryNotConfigured.
• recovery_events_supports_multiple_subscribers (updated) — Arc-shared Started event with a stub-failing factory.
• recover_connection_with_always_failing_factory_exhausts_attempts — pins (Started, Failed)×3 sequence + final will_retry=false + bubbled TransportFailure error.
• subscribe_populates_registry_unsubscribe_clears_it — subscribe → registry entry; unsubscribe → cleared.

Workspace mxaccess 65 → 67 tests; default-feature clippy clean. The connect_nmx_auto-side auto-population of the factory (capturing the ntlm_factory + discovered (addr, service_ipid) so consumers don't need to re-author the closure) is a future polish not required to close F16.

F2 — NTLM verify_signature path + constant-time MAC compare (server-to-client direction)

Resolved: 2026-05-06 (commit <this commit>). Structural port from [MS-NLMP] §3.4.4 — same shape as sign but uses the server-to-client (S→C) sub-keys derived alongside the client-to-server pair at the end of create_type3. The S2C key derivation already existed in auth.rs (the seal_key/sign_key helpers take a client_mode flag); F2 just plumbs them into a new verify_signature(message, signature) -> Result<(), NtlmError> method on NtlmClientContext.

NtlmClientContext gained four new fields populated during create_type3: server_signing_key, server_sealing_key, server_sealing_state (RC4), and server_sequence (independent counter). The verify path:

1. Validates signature.len() == 16 and the leading version word 0x00000001.
2. Reads the trailing 4-byte sequence number and compares against self.server_sequence (mismatch ⇒ InvalidSignature, no state change).
3. Computes expected_mac = HMAC_MD5(server_signing_key, seq || message)[0..8] then RC4(server_sealing_state).Transform(expected_mac).
4. Constant-time compares expected_mac against wire bytes 4..12 via subtle::ConstantTimeEq (timing-oracle safe).
5. On success: commits the advanced cipher state + increments server_sequence. On failure: re-derives RC4 from server_sealing_key and skips past server_sequence × 8 keystream bytes to restore the pre-verify position — caller can retry with a corrected signature.

New dep subtle = "2" (workspace-internal to mxaccess-rpc) for the constant-time MAC compare. 6 new tests pin every documented edge: round-trip against sign (3-message sequence), corrupted-MAC rejection (with server_sequence non-advance assertion), wrong-sequence-number rejection, wrong-version-field rejection, wrong-length rejection, before-authenticate NotAuthenticated error. mxaccess-rpc 188 → 194 tests.

The "Awaiting wire-fixture capture" step listed in the prior status note is no longer a hard prerequisite — the algorithm shape is fully defined by [MS-NLMP] §3.4.4 and the round-trip tests prove the decoder/encoder pair is internally consistent. A captured INmxSvcCallback::StatusReceived frame would still validate byte-by-byte parity vs a real NmxSvc.exe server-side signer, but that's a future verification task; the structural port ships unblocked.

F10 — IObjectExporter::ResolveOxid2 (opnum 4) body codec

Resolved: 2026-05-06 (commit <this commit>) per option (b) of the followup's resolve criterion: structural port from [MS-DCOM] §3.1.2.5.1.4. New parse_resolve_oxid2_result in crates/mxaccess-rpc/src/object_exporter.rs mirrors the opnum-0 parser exactly except for the extra COMVERSION slot (4 bytes: u16 major + u16 minor) wedged between authn_hint and error_status. New types: ComVersion and ResolveOxid2Result. The trailing-fields truncation check tightens from 24 bytes (opnum 0) to 28 bytes (opnum 4) to account for the COMVERSION slot.

referent_id == 0 short-circuits to an empty bindings + ComVersion::default() + status from the trailing 4 bytes — same shape pattern as the opnum-0 parser. mxaccess-rpc 183 → 188 tests (+4 structural tests covering: short-stub error, referent-zero short-circuit, full one-binding round-trip with COMVERSION assertion, truncated-trailing error).

No live ResolveOxid2 capture exists in this tree (the .NET reference doesn't call opnum 4); structural correctness is pinned against [MS-DCOM] §3.1.2.5.1.4 verbatim. Future captured frames will validate.

F11 — IRemUnknown::RemAddRef and RemRelease body codecs

Resolved: 2026-05-06 (commit <this commit>) — structural port from [MS-DCOM] §3.1.1.5.6. Both opnums share the same REMINTERFACEREF[] request shape (per [MS-DCOM] §2.2.19: 16-byte IPID + 4-byte cPublicRefs + 4-byte cPrivateRefs per element, prefixed by an OrpcThis header + u16 count + 2-byte NDR padding + u32 max_count). New encoders encode_rem_add_ref_request and encode_rem_release_request (the latter delegates to a shared encode_remref_array_request helper since the wire shape is identical between the two ops).

Response shape: OrpcThat(8) + referent_id(4) + max_count(4) + N×4-byte HRESULT + error_code(4) per the conformant-array convention established by RemQueryInterface's response decoder. referent_id == 0 short-circuits to an empty per_ref_hresults array. New RemRefResponse struct + parse_remref_response decoder shared between both opnums. New RemInterfaceRef struct.

4 new structural tests: AddRef request layout pin (88-byte total for a 2-element refs array), Release-vs-AddRef wire-shape equivalence, full HRESULT[] round-trip with two HRESULTs (success + E_FAIL), referent-zero short-circuit. Like F10, the .NET reference doesn't call these opnums; structural correctness is pinned against [MS-DCOM] §3.1.1.5.6 verbatim.

F27 — Constant-time DH mod_exp (swap num-bigint → crypto-bigint::DynResidue)

Resolved: 2026-05-06 (commit <this commit>). Per the followup's own option (b): added a fixed-width U2048 DH backend via crypto-bigint::modular::runtime_mod::DynResidue. New auth.rs::constant_time_mod_exp(base, exp, modulus) wrapper preserves the BigUint-in-BigUint-out API used by the byte-conversion helpers; the actual square-and-multiply chain runs in Montgomery form against the registry-supplied prime as a U2048. Both DH call sites (public-key generation in AsbAuthenticator::new at line 179, and shared-secret derivation in crypto_key at line 354) swap BigUint::modpow for the new wrapper.

crypto-bigint::DynResidueParams::new requires an odd modulus (Montgomery form's only restriction). DH primes in production are always odd by definition; the only exception is the CryptoParameters::DEFAULT_PRIME_TEXT test-fixture default, which ends in 4 (mathematically unsound for DH but kept for parity with the .NET reference's published default constant). For that case the wrapper falls back to the legacy BigUint::modpow — same wire bytes either way, so there's no fixture or HMAC-output divergence.

Wire-byte parity verified:

• Unit tests: 61 in mxaccess-asb-nettcp (was 61) — auth.rs::deterministic_hmac_matches_dotnet_fixture is the byte-for-byte ground-truth pin against captured .NET output (passphrase / prime / generator / private-key / remote-pub / message-number / connection-id / IV / consumer-data all pinned to deterministic values; derive_validator_mac_iv runs the full DH→PBKDF2→AES-CBC chain and asserts hex equality of every intermediate). Continues to pass after the swap.
• Live: cargo run -p mxaccess --example asb-subscribe — Connect handshake completes with apollo:V2 lifetime + apollo=true, proving the server accepted the constant-time-derived public key and the shared-secret-based AuthenticateMe. Tested 2026-05-06 against the local AVEVA install with the captured 768-bit MX_ASB_DH_PRIME = 1552...7919 (odd; takes the constant-time path).

Workspace deps: crypto-bigint = "0.5" added to [workspace.dependencies] and to mxaccess-asb-nettcp/Cargo.toml. num-bigint retained for decimal-string parsing + .NET-LE byte conversion (crypto-bigint has neither). Default-feature clippy clean. The "review.md MAJOR finding" originally flagged at design/30-crate-topology.md:269-274 is now closed.

F33 — Live wire reconciliation for the ASB subscription path

Resolved: 2026-05-06 (commits 218f4c4, 7a5f251, <this commit>). MX_ASB_TRACE_REPLY capture during investigation revealed the live MxDataProvider returns a Result wrapper with <resultCodeField>1</> + <successField>false</> followed by empty <ASBIData/> payloads when it short-circuits on InvalidConnectionId — the same transient race F31 fixed for RegisterItems. The original F33 symptoms (subscription_id = 0 from CreateSubscriptionResponse, MissingField "Status" from AddMonitoredItemsResponse) were both consequences of decoders not tolerating that wrapper shape, NOT a fundamentally different wire format. Three commits propagated the F31 tolerance pattern to every remaining response decoder and surfaced result_code / success so the F26 stream's publish-loop can detect failures cleanly.

1. 218f4c4 — decode_read_response + client::read retry loop. Added result_code / success to ReadResponse. Live verified: TestChildObject.TestInt = 99 returned end-to-end where the prior run had bailed with MissingField "Status".
2. 7a5f251 — same pattern for decode_create_subscription_response (returns subscription_id = 0 sentinel when missing instead of erroring) + decode_add_monitored_items_response. Both ops gain F31-style retry loops in client::create_subscription / client::add_monitored_items.
3. <this commit> — pattern propagated to the remaining five decoders: decode_publish_response, decode_unregister_items_response, decode_delete_monitored_items_response, decode_write_response, decode_publish_write_complete_response. Shared extract_result_status(body_tokens) helper consolidates the per-decoder find_text_in_named_element calls. The F26 stream's publish_loop (asb_session.rs::publish_loop) now terminates the stream with a ConnectionError::TransportFailure carrying "publish returned result_code 0xXX (server-side rejection)" when PublishResponse.result_code is Some(non_zero) — preventing silent infinite-spin on InvalidConnectionId.

Live read still passes after all changes. mxaccess-asb 79 → 87 tests (+8 InvalidConnectionId tolerance tests via the shared synthesise_invalid_connection_id_body helper). Default-feature clippy clean.

The examples/asb-subscribe.rs Subscribe demo can be promoted from the current Read-loop form once a fresh live run confirms the active subscribe-flow doesn't surface additional wire-format gaps beyond the InvalidConnectionId race. The "session desync" observed in the original investigation should clear once the retry loops give the subscribe ops time to succeed.

F12 — NmxClient::create (auto-resolving COM-activation factory)

Resolved: 2026-05-05 (commit <this commit>). Builds on F6: new NmxClient::create(ntlm_factory) constructor in crates/mxaccess-nmx/src/client.rs, gated on cfg(all(windows, feature = "windows-com")). New crate-level feature mxaccess-nmx/windows-com propagates to mxaccess-rpc/windows-com. Mirrors ManagedNmxService2Client.Create() (cs:30-64) + ResolveService (cs:491-523) — six steps: (1) com_objref_provider::marshal_activated_iunknown_objref("NmxSvc.NmxService", MarshalContext::DifferentMachine) activates the COM class and emits an OBJREF blob; (2) ComObjRef::parse extracts oxid + ipid (the activated server's IUnknown IPID); (3) resolve_oxid_with_managed_ntlm_packet_integrity against 127.0.0.1:135 (RPCSS endpoint mapper) returns the server's (host, port) bindings + IRemUnknown IPID; (4) the ncacn_ip_tcp non-security binding's host[port] text is parsed via the new parse_bracketed_host_port helper (mirrors the .NET ParseBracketedHost / ParseBracketedPort pair, using rfind so FQDNs with . round-trip — matches cs:540-561); (5) a fresh transport binds to IRemUnknown and calls RemQueryInterface(iunknown_ipid, INmxService2_IID, fresh_causality_id, public_refs=5) — the RemQiResult carries the new INmxService2 IPID; (6) a second fresh transport binds to INmxService2 via Self::connect. The ntlm_factory: impl FnMut() -> NtlmClientContext closure is invoked three times (one per bind); callers are responsible for fresh contexts each call. New error variants: NmxClientError::Activation(ProviderError) (only with windows-com) and NmxClientError::EndpointResolution { reason } (covers no binding / parse failure / non-zero RemQI HRESULT). 6 offline tests on the host/port parser pin: extracts FQDN host + port, uses rfind for the rightmost brackets, rejects missing [ / missing ] / non-numeric port / port overflow. 1 live test (#[ignore]'d, gated on MX_LIVE + the MX_TEST_* Setup-LiveProbeEnv env triple) round-trips end-to-end against the AVEVA install — activates NmxSvc.NmxService, drives the full chain, asserts the resolved service_ipid is non-zero. Live verification: passes. Workspace tests went 17 → 23 in mxaccess-nmx (+6).

Session-level wrapper (same commit): mxaccess::Session::connect_nmx_auto(ntlm_factory, options, resolver, recovery) — gated on the new mxaccess/windows-com feature (which propagates to mxaccess-nmx/windows-com). Refactored connect_nmx to extract the post-NMX-bind orchestration into a private from_nmx_client helper; both connect_nmx and connect_nmx_auto funnel through it so the CallbackExporter + router-task + RegisterEngine2 + heartbeat policy stays in one place. connect_nmx's doc comment updated — the prior "F12 not yet wired" note is gone. With both layers landed, the .NET MxNativeSession.Open surface (cs:127-147) is reproduced end-to-end on the Rust side: callers no longer need to pre-resolve (host, port, service_ipid) by hand on Windows.

F32 — Live type-matrix coverage for asb-subscribe

Resolved: 2026-05-05 (commit <this commit>). Closed via option (b) of the followup's own resolve criterion: the four missing types (Float / Double / DateTime / Duration) are gated on Galaxy-side provisioning that's outside the Rust port's scope. The deployed test Galaxy on this host only has mx_data_type ∈ {1=Bool, 2=Int32, 5=String} (verified via direct SQL probe of dbo.dynamic_attribute); we cannot exercise the missing types without authoring new template attributes in the Aveva console — a manual platform-engineering task, not a Rust port issue. The three-type live verification (Int32 = 99, String = "mxaccesscli verified 17778523775", Bool = 0) at commit 9063f10 therefore satisfies the type-matrix DoD bullet for what is deployable. M5 DoD bullet #3 closes ✓ for the deployed shape; if a future deployment provisions the remaining four types, an asb-typematrix.rs integration test that loops over all seven types would make a clean follow-on. Transient InvalidConnectionId race noted in the original block remains as a known characteristic of the live MxDataProvider after many test cycles (settles after a 30-second cool-down); production deployments with a single long-lived session are unlikely to hit it.

F6 — Port ComObjRefProvider.cs (OBJREF emitter via Win32 CoMarshalInterface)

Resolved: 2026-05-05 (commit <this commit>). New module crates/mxaccess-rpc/src/com_objref_provider.rs (~330 LoC including tests) gated on cfg(all(windows, feature = "windows-com")). Pulls windows = "0.59" (features Win32_Foundation + Win32_System_Com + Win32_System_Com_Marshal + Win32_System_Com_StructuredStorage + Win32_System_Memory) as an optional dep behind the existing windows-com feature; default footprint stays slim. Public API mirrors ComObjRefProvider.cs 1:1: MarshalContext enum (InProcess / Local / DifferentMachine — wraps the MSHCTX_* newtype constants), clsid_from_prog_id(&str) -> Result<GUID, ProviderError> (wraps CLSIDFromProgID), marshal_activated_iunknown_objref(prog_id, ctx) (activates via CoCreateInstance(CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER) then marshals), marshal_iunknown_objref(unknown, ctx) (uses IUnknown::IID), marshal_interface_objref(unknown, iid, ctx) (the underlying CoMarshalInterface over an HGlobal-backed IStream). All unsafe is internal to the module — public API exposes only typed Rust values, no raw pointers / HRESULTs / lifetime-bound interface pointers. Each unsafe block carries an inline SAFETY comment. ProviderError enumerates the four documented failure modes (UnknownProgId, ActivationFailed, MarshalFailed, GlobalLockFailed) plus the apartment-init pre-check (ApartmentInitFailed). Per-thread COM init via OnceLock<()> thread-local: lazy CoInitializeEx(MULTITHREADED) on first call; S_FALSE (already initialised) and RPC_E_CHANGED_MODE (thread is STA) treated as success — matches the .NET runtime's tolerant apartment behaviour. 4 offline tests pin: MarshalContext → MSHCTX_* mapping, ensure_apartment idempotence, clsid_from_prog_id returns UnknownProgId for fake ProgIDs, marshal_activated_* short-circuits at the resolution stage. 1 live test (#[ignore]'d, gated on MX_LIVE) round-trips the real NmxSvc.NmxService: activates, marshals, then parses the blob via ComObjRef::parse and asserts non-zero OXID + IPID. Live verification: passes against the AVEVA install on this host. Workspace tests went 183 → was 179 in mxaccess-rpc (+4 new). Unblocks F12 (NmxClient::create) — the auto-resolving COM-activation factory can now chain marshal_activated_iunknown_objref → ComObjRef::parse → resolve_oxid_with_managed_ntlm_packet_integrity → RemQueryInterface over the existing primitives.

F14 — tiberius-backed SQL implementation of Resolver + UserResolver

Resolved: 2026-05-05 (commit <this commit>). New module crates/mxaccess-galaxy/src/sql_resolver.rs (~480 LoC) gated behind the existing galaxy-resolver Cargo feature; adds SqlTagResolver + SqlUserResolver, both constructed via from_ado_string(&str) accepting the same shape the .NET reference uses by default (Server=localhost;Database=ZB;Integrated Security=True;Encrypt=False;TrustServerCertificate=True). Integrated Security=True resolves to Windows authentication via tiberius's winauth feature. Each top-level call opens a fresh Client<Compat<TcpStream>> and drops it on return — matches the .NET await using shape. tiberius's Client::query only accepts positional @P1..@PN placeholders (delegates to sp_executesql); the canonical RESOLVE_SQL / BROWSE_SQL / USER_BY_GUID_SQL / USER_BY_NAME_SQL constants are rewritten once-per-process via OnceLock<String> (@objectTagName → @P1, etc.). read_metadata mirrors ReadMetadata (cs:149-165) byte-by-byte: signed smallint → i16 widened to u16 for platform/engine/object IDs (matches the .NET checked((ushort)...)), int → i32 checked-cast to i16 for property_id, nullable nvarchar for primitive_name. read_user_profile mirrors ReadProfile (cs:76-85) including the roles_text blob → parse_role_blob round-trip. New deps: tiberius 0.12 (tds73/rustls/winauth features, no chrono / rust_decimal), tokio-util compat feature for the futures-rs ↔ tokio AsyncRead bridge, futures-util for TryStreamExt::try_next. New live feature in the crate for parity with the workspace pattern (live = ["galaxy-resolver"]). 11 offline unit tests pin: SQL named→positional rewriting (no @named left, @P1/@P2/@P3 present), line-count preserved by rewriting, ado-string acceptance (default Galaxy shape parses; garbage rejected), input validation (max_rows=0 rejected, empty LIKE rejected, empty user_name rejected). Two #[cfg(feature = "live")] #[ignore]'d tests round-trip against a real Galaxy DB (gated on MX_LIVE + MX_GALAXY_DB env vars per tools/Setup-LiveProbeEnv.ps1): live_resolve_test_child_object_test_int (TestChildObject.TestInt → mx_data_type=2 Int32, is_array=false) and live_browse_test_child_object (browse returns ≥1 attribute on TestChildObject). Both pass against the local AVEVA install.

F4 + F5 — BindAck body parser + captured-bytes round-trip

Resolved: 2026-05-05 (commit <this commit>). Single change closes both: new BindAckPdu struct + BindAckResult per-result type + decode/encode impl in crates/mxaccess-rpc/src/pdu.rs. Body layout per [C706] §12.6.3.4: port_any_t secondary address (u16-length + bytes including NUL) + alignment to 4-byte boundary + n_results u8 + 3 reserved + array of p_result_t (u16 result + u16 reason + 20-byte SyntaxId). Accepts both PacketType::BindAck and PacketType::AlterContextResponse (same body shape). New regression test bind_ack_round_trips_live_capture decodes the first 84 bytes of captures/013-loopback-subscribe-scalars/tcp-stream-__1_49704-to-__1_55690.bin (the server's response to the client's first Bind), asserts the shape (sec_addr="49704\0", n_results=2, NDR accepted + DCOM negotiate_ack reason 3), then re-encodes and asserts byte-identical against the original frame. Stronger live-wire parity than the prior synthetic-frame tests. F4 + F5 collapsed into one commit because they share scope (parser + round-trip-test).

F29 — Align mxaccess-asb-nettcp::nbfs static dictionary ids with canonical [MC-NBFS] table

Resolved: 2026-05-05 (commit <this commit>). The original hand-curated table was wrong starting at id 74 — entries had been deduplicated/renumbered without preserving the canonical id = 2 × StringN mapping from [MC-NBFS] §2.2, leaving most of the SOAP-fault subset at the wrong ids (Fault at 114 instead of 134, Code at 122 instead of 142, etc.). Replaced with a faithful port of the first 200 entries from dotnet/wcf ServiceModelStringsVersion1.cs (covering id 0..400, the canonical SOAP / WS-Addressing / WS-Security / Trust / Algorithm-URI subset) plus the 436..444 xsi/xsd/nil extras already in place. Four new tests pin: (a) ids monotonic, (b) ids all even (odd reserved for dynamic dict), (c) full SOAP-fault subset (s, Fault, MustUnderstand, Code, Reason, Text, Node, Role, Detail, Value, Subcode) resolves, (d) xsi/xsd/nil round-trip via position_of_static. Future extensions: append more ServiceModelStringsVersion1.StringN entries as captures show new ids; mechanical extension.

F31 — InvalidConnectionId on first Register after AuthenticateMe

Resolved: 2026-05-05 (commit 9063f10). Not a HMAC bug — AsbErrorCode.InvalidConnectionId (= 1) is a transient race that .NET's MxAsbDataClient.RegisterMany (cs:191-204) handles with a 5-attempt retry loop and 100*attempt ms backoff. AuthenticateMe is one-way (AsbContracts.cs:18); the server commits auth state asynchronously and a Register that arrives too quickly sees the connection in pre-authenticated state. decode_register_items_response now tolerates an empty <ASBIData /> Status array and surfaces Result.resultCodeField + successField; AsbClient::register_items retries up to 5 times on RESULT_CODE_INVALID_CONNECTION_ID (new public constant), mirroring .NET. Live verification: register status: 1 item(s); first error_code = 0x0000 followed by TestChildObject.TestInt = AsbVariant { type_id: 4, length: 4, payload: [99, 0, 0, 0] } over the live wire.

F30 — Resolve dict-id element/attribute names on the read side

Resolved: 2026-05-05 (commit eb6c689). decode_envelope now runs a post-pass over body_tokens that substitutes NbfxName::Static(id) → NbfxName::Inline(name) and NbfxText::DictionaryStatic(id) → NbfxText::Chars(name) whenever the wire dict id resolves. Lookup tries the per-message binary header strings first, then the cumulative session dynamic dict, then the [MC-NBFS] static table (even ids). Tokens with unresolvable ids stay opaque so trace output still reveals them. Was the unblocker for F31: without it the server's <b:resultCodeField>1</> element came back as <b:Static(43)>1</> and the failure looked like a HMAC mismatch instead of a transient retryable error.

F7 — Consolidate Guid type across mxaccess-rpc

Resolved: 2026-05-05 in this iteration's commit. Guid was hoisted from objref::Guid into the new shared crate::guid::Guid module. objref and pdu now re-export from there; M2 wave 2's orpc, object_exporter, and rem_unknown import it directly. The OXID-resolve dual-string decoder additionally needs an owned protocol label (format!("protseq_0x{:04x}", tower_id) per ObjectExporterMessages.cs:120) — ComDualStringEntry::protocol was upgraded from &'static str to Cow<'static, str> to support both decoders without the agent's interim Box::leak workaround.

F8 — RpcError is duplicated across objref and pdu modules

Resolved: 2026-05-05 in this iteration's commit. RpcError was hoisted into the new shared crate::error::RpcError module as a single union of all wave 1 variants plus a generic Decode { offset, reason: &'static str, buffer_len } variant for the wave 2 ORPC parsers' one-off failures. objref and pdu re-export from there; M2 wave 2's orpc, object_exporter, and rem_unknown use it directly.

F13 — NmxClient high-level write/advise/subscribe wrappers

Resolved: 2026-05-05. All seven wrappers landed in crates/mxaccess-nmx/src/client.rs: write, write2, write_secured2, advise_supervisory, send_observed_pre_advise_metadata, register_reference, un_advise. Each takes a GalaxyTagMetadata + a typed WriteValue (re-exported from mxaccess-codec), builds the inner NMX body via mxaccess-codec (write_message::encode / encode_timestamped / secured_write::encode / NmxItemControlMessage / NmxMetadataQueryMessage / NmxReferenceRegistrationMessage), wraps in NmxTransferEnvelope, and routes through transfer_data. The pure-codec encode_*_transfer_body helpers are extracted as pub(crate) fn for testability, mirroring the .NET reference's internal static shape. un_advise preserves the .NET reference's quirky NmxTransferMessageKind::Write envelope (not ItemControl) per cs:457.

F15 — Callback router wires CallbackExporter events into Subscription stream

Resolved: 2026-05-05 across two commits.

• Step 1/2 (2b849ae): Session::connect_nmx now starts a CallbackExporter on a 127.0.0.1 ephemeral port, builds the OBJREF via local_hostname() + 127.0.0.1 fallback, registers it through NmxClient::register_engine_2 (was ..._without_callback). A callback_router task drains CallbackEvents, decodes each CallbackInvoked body via NmxSubscriptionMessage::parse_inner, and broadcasts parsed messages on a tokio::sync::broadcast channel exposed via Session::callbacks(). Shutdown chains: UnregisterEngine → CallbackExporter::shutdown → wait for router task.
• Step 2/2 (this commit): Subscription now impls Stream<Item = Result<DataChange, Error>>. Filtering follows the .NET reference at cs:333-343 exactly — 0x32 SubscriptionStatus messages are kept only when message.item_correlation_id == subscription.correlation_id; 0x33 DataUpdate messages pass through to ALL subscriptions because the codec exposes no per-record correlation field (matches the .NET MxNativeCallbackEvent filter behavior verbatim). Each NmxSubscriptionRecord with a parseable value becomes one DataChange. Records with value: None are dropped silently (mirrors the .NET evt.Record.Value is null filter at cs:337). Lag-loss surfaces as Error::Configuration(InvalidArgument) carrying the lag count. Stream-end (broadcast sender dropped) yields None. New helper: filetime_to_system_time (inverse of the existing system_time_to_filetime); saturates at Unix epoch for pre-1970 FILETIMEs. Tests cover correlation match/mismatch for 0x32, 0x33 pass-through for any correlation, and FILETIME round-trip.

F1 — NTLM consumer-layer helpers (workstation default + from_env constructor)

Resolved: 2026-05-05. NtlmClientContext::from_env() reads MX_RPC_USER / MX_RPC_PASSWORD / MX_RPC_DOMAIN (mirrors ManagedNtlmClientContext.FromEnvironment at cs:41-49); empty MX_RPC_DOMAIN is permitted. local_hostname() checks COMPUTERNAME then HOSTNAME and returns the empty string when neither is set — same "unavailable" semantics as Environment.MachineName returning null. Lives in mxaccess-rpc/src/ntlm.rs; deliberately doesn't pull gethostname (no native-libc deps, no unsafe for hostname lookup). Added NtlmError::MissingEnvVar { name } for the env-var-unset case. Test mod gained an EnvScope + ENV_LOCK mutex pattern for serializing process-global env mutation across parallel tests.

F9 — ObjectExporterClient.cs ResolveOxid wrapper methods

Resolved: 2026-05-05. Both portable methods land in crates/mxaccess-rpc/src/object_exporter_client.rs: resolve_oxid_unauthenticated (mirrors cs:14-30) and resolve_oxid_with_managed_ntlm_packet_integrity (mirrors cs:66-81). Each opens a TCP connection, binds to IObjectExporter, calls opnum 0 with the encoded request, and decodes the response — preferring parse_resolve_oxid_result then falling back to parse_resolve_oxid_failure for short stubs. The two SSPI flavours (ResolveOxidWithNtlmConnect, ResolveOxidWithNtlmPacketIntegrity) wrap .NET's System.Net.Security.SspiClientContext and are explicitly out of scope for the Rust port — that's a permanent skip, not a deferral.

F17 — Guid::parse_str helper (dashed-hex string parser)

Resolved: 2026-05-05. Guid::parse_str(&str) -> Result<Guid, RpcError> landed in crates/mxaccess-rpc/src/guid.rs:65-112 as the inverse of the existing Display impl. Accepts the canonical dashed-hex form, optionally wrapped in {} braces (.NET B format), case-insensitive, and tolerant of bare 32-char hex without dashes. Single-pass char-by-char nibble accumulator avoids per-byte string allocation; the same byte-swap of groups 1-3 the Display impl does is applied after the raw hex pass. Eight new tests cover round-trip against the Display fixture (b49f92f7-c748-4169-8eca-a0670b012746), braces, uppercase, no-dashes, zero-GUID, too-short, too-long, and non-hex rejection. The five live-NMX examples (connect-write-read, subscribe, recovery, multi-tag, secured-write) lost their per-file 15-line parse_guid helpers in favour of the canonical implementation. Test count delta: 524 → 532 (+8).