Files
mxaccess/design
Joseph Doherty df3457c54a [F56] subscribe / subscribe_buffered: split-form wire body + diagnose Galaxy fixture gap
Three real fixes + one architectural diagnosis:

1. Session::subscribe_buffered_nmx now sends the .NET-reference split
   form on the wire:
     item_definition = "<attr>.property(buffer)"   (was: full reference)
     item_context    = "<object_tag_name>"          (was: empty)
     item_handle     = SessionInner::next_item_handle.fetch_add(1)
                       (was: hardcoded 0)
   Verified byte-identical against captures/082 + 094 by the existing
   buffered_register_reference_parity unit tests. The
   item_handle counter mirrors MxNativeCompatibilityServer's
   _nextItemHandle++ at MxNativeSession.cs:613.

2. New live tests:
   - tests/buffered_subscribe_live.rs (F49 step 1) — uses real Galaxy
     metadata via SqlTagResolver + connect_nmx_auto, drives a
     background writer at 500ms cadence to force value-changes,
     drains DataChange events from Subscription.
   - tests/plain_subscribe_live.rs — same harness over plain
     Session::subscribe (NOT buffered), used to isolate whether
     "no DataUpdate" is buffered-specific (it's not — both fail).

   Both pull tracing-subscriber as a dev-dep so `RUST_LOG=trace`
   surfaces dcom_sink + router activity.

3. mxaccess-galaxy/sql_resolver.rs: drop the inner-attribute
   `#![cfg(feature = "galaxy-resolver")]` — the module-level cfg on
   `pub mod sql_resolver` in lib.rs already handles this and Rust
   1.85's clippy::duplicated_attributes lint flagged the duplicate
   once mxaccess-compat dev-deps activated the feature.

4. F56 finding (diagnosis, NOT a bug fix): the engine on this Galaxy
   install does not have an active value for TestChildObject.TestInt.
   Confirmed by running the .NET reference's own probe:

     dotnet run --project src/MxNativeClient.Probe -c Release \
       -- --probe-session-subscribe --tag=TestChildObject.TestInt \
       --subscribe-hold-seconds=10

   ...returns ONE 0x32 SubscriptionStatus (status=3 detail=3
   quality=0x00C0 Uncertain value=null) and zero 0x33 DataUpdates —
   matching the Rust port's symptom exactly. Not a Rust port bug,
   not a wire-byte gap. F49 steps 1-3 need either an actively-
   scanned tag or local Galaxy reconfiguration to scan
   TestChildObject.TestInt.

Workspace tests + clippy clean under both feature configurations.
F56 entry in design/followups.md updated with the full diagnostic
chain so future-me / future-collaborators can pick it up without
re-tracing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-06 10:27:08 -04:00
..

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 M2M6 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 .cs file path in src/MxNativeCodec/, src/MxNativeClient/, or src/MxAsbClient/, or
  • a docs/*.md spec file, or
  • a captures/0NN-frida-* directory or analysis/frida/*.tsv row.

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.md for the per-phase parallelism map.
  • Driving M2M6 autonomously via /loop: prompt.md (and the followups.md triage log it maintains).