Joseph Doherty
af15fe7587
The router used to call NmxSubscriptionMessage::parse_inner directly on the COM-stub-delivered body, but the wire bytes arrive wrapped in a ProcessDataReceived envelope (46-byte header + optional 4-byte length prefix); parse_inner expects post-envelope bytes. Result: every 0x33 DataUpdate that ever arrived was silently dropped. Mirrors the .NET reference's MxNativeSession.OnCallbackReceived flow at cs:582-606 — three sequential parse attempts: 1. NmxOperationStatusMessage::try_parse_process_data_received_body (already wired) 2. NmxReferenceRegistrationResultMessage::try_parse_... (NEW — was missing) 3. NmxSubscriptionMessage::try_parse_process_data_received_body (NEW — was wrong) Adds: - NmxSubscriptionMessage::try_parse_process_data_received_body — peels envelope via NmxObservedEnvelope::parse_process_data_received_body_flexible, then dispatches to existing parse_inner. - NmxReferenceRegistrationResultMessage::try_parse_process_data_received_body — same shape, for the 0x11 registration-result frame. - Router branch for 0x11 — currently traces the assigned item_handle and drops the frame (matches the .NET reference, which fires a ReferenceRegistrationReceived event with no consumer in the codebase). - Router fall-through trace! when neither path matches, so future unparseable bodies surface in RUST_LOG=trace instead of vanishing. - DcomCallbackSink::forward — trace! per inbound callback so RUST_LOG=mxaccess_callback=trace surfaces opnum + size. - crates/mxaccess-compat/tests/buffered_subscribe_live.rs — F49 step 1 live test that drives subscribe_buffered + a 500ms-cadence writer. Also pulls tracing-subscriber as a dev-dep so the test can dump router activity. Existing router_task_decodes_callback_invoked_into_broadcast unit test updated to wrap its synthetic 0x32 body in an envelope so the new parse path actually accepts it. Live result: F56 — the buffered round-trip *registers* successfully (RegisterReference returns HRESULT 0; engine sends one 0x11 RegistrationResult + one 51-byte op-status per write, perfectly clocked) but the engine never sends a 0x33 DataUpdate. Rust-port- specific gap vs the .NET reference's working buffered path; root cause is likely a field-level difference in the RegisterReference body or a missing post-RegisterReference step. Captured as F56 in design/followups.md, blocking F49 step 1; F56's DoD is the same live test reporting >=3 DataChange arrivals. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
design/ — Rust port architectural plan
This folder is the design contract for the Rust replacement of AVEVA/Wonderware MXAccess. It is the gap between the .NET reference in src/ and the Rust crates that will be written under a sibling rust/ workspace (per CLAUDE.md).
The folder is structured as a small set of focused documents. Read in order; each builds on the previous.
| File | Purpose |
|---|---|
00-overview.md |
Mission, two-layer goal, architectural principles, non-goals |
10-raw-layer.md |
Byte-accurate raw MXAccess layer (codec + transport + session) |
20-async-layer.md |
Idiomatic Tokio async layer on top of the raw layer |
30-crate-topology.md |
Cargo workspace, crates, dependencies, build/test commands |
40-protocol-invariants.md |
Bill of materials: IIDs, opnums, envelope/handle bytes |
50-error-model.md |
MxStatus, error types, panic/cancellation policy |
60-roadmap.md |
Milestones M0..M6, validation strategy |
70-risks-and-open-questions.md |
Parity gaps, unproven flows, cross-platform constraints |
dependencies.md |
Cross- and within-milestone parallelism map; agent budget per phase |
review.md |
Adversarial review log (BLOCKER/MAJOR/MINOR/NIT findings, all resolved) |
prompt.md |
/loop driver prompt for autonomous M2–M6 execution |
followups.md |
Open / resolved deferred work items; auto-triaged by prompt.md Step 0 (created on first /loop run if missing) |
The design is grounded in the .NET reference at src/ and the protocol artifacts in docs/, analysis/, and captures/. Do not introduce protocol behavior in these documents that is not already proven in the reference. When adding a new claim about wire format, cite either:
- a
.csfile path insrc/MxNativeCodec/,src/MxNativeClient/, orsrc/MxAsbClient/, or - a
docs/*.mdspec file, or - a
captures/0NN-frida-*directory oranalysis/frida/*.tsvrow.
This folder is documentation, not code. When the Rust workspace is created, the design here is the contract it must satisfy. When evidence in captures/ invalidates a design decision here, update the design first, then the code.
Reading order
- New contributor: 00 → 30 → 10 → 40 → 20 → 50 → 60 → 70.
- Protocol question: 40 first, then the relevant section of 10.
- API question: 20 first, then 50.
- Planning a milestone: 60 first, cross-reference 70 for blockers.
- Scheduling concurrent work:
dependencies.mdfor the per-phase parallelism map. - Driving M2–M6 autonomously via
/loop:prompt.md(and thefollowups.mdtriage log it maintains).