# Follow-up #10 — Wire CapabilityInvoker into the production dispatch layer (RESILIENCE-DISPATCH-GAP)

> **Status:** OPEN · **Surfaced by:** guard 07/C-1 (wiring the OTOPCUA0001 analyzer) on
> `fix/archreview-c1-wire-analyzer` `f0082af5` · **Task:** TaskCreate #10 · **Severity:** likely High ·
> **Effort:** M–L · **Risk:** Medium (behavior-changing hot path). See [`STATUS.md`](STATUS.md).

## The finding

Wiring the custom `UnwrappedCapabilityCallAnalyzer` (OTOPCUA0001) tree-wide surfaced that the entire
**Phase 6.1 `CapabilityInvoker` resilience pipeline is constructed only in tests** — it is instantiated
nowhere in production. The production dispatch layer calls driver-capability methods
(`IReadable`/`IWritable`/`ISubscribable`/`ITagDiscovery`/`IAlarmSource`) **directly**, bypassing the
retry / circuit-breaker / bulkhead / tracker-telemetry pipeline entirely.

`CapabilityInvoker`'s own XML doc falsely claims: *"The server's dispatch layer routes every capability
call … through this invoker."* It does not. This is the exact "built-but-never-wired" class the whole
arch review targets — the analyzer did its job on the first wiring.

### Evidence
- `grep -rn "new CapabilityInvoker"` → only `tests/Core/…` (7 test files). Zero production constructions.
- `DriverInstanceActor` holds a raw `IDriver _driver` and calls it directly at 6 sites.
- `GenericDriverNodeManager.BuildAddressSpaceAsync` calls `discovery.DiscoverAsync` directly (1 site).

### The 7 deferred sites (all marked `#pragma warning disable OTOPCUA0001 // RESILIENCE-DISPATCH-GAP`)
Grep the marker to find them: `grep -rn "RESILIENCE-DISPATCH-GAP" src`.

| File | ~line | Call |
|---|---|---|
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 575 | `writable.WriteAsync` |
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 623 | `src.AcknowledgeAsync` |
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 660 | `subscribable.SubscribeAsync` |
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 685 | `subscribable.UnsubscribeAsync` |
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 762 | `src.SubscribeAlarmsAsync` |
| `src/Server/…/Runtime/Drivers/DriverInstanceActor.cs` | 821 | `discovery.DiscoverAsync` |
| `src/Core/…/Core/OpcUa/GenericDriverNodeManager.cs` | 71 | `discovery.DiscoverAsync` |

> These are distinct from the 3 **driver-internal self-call** sites (AbCipAlarmProjection ×2, S7Driver ×1)
> which are `#pragma`'d as *intentional* — a driver must not re-wrap its own internal poll/ack calls; the
> invoker wraps the driver from the dispatch layer OUTWARD. Do NOT touch those.

## Why it wasn't fixed inside 07/C-1

07/C-1's scope was "wire the analyzer + triage." Actually routing all 7 sites through `CapabilityInvoker`
is a substantial, behavior-changing hot-path remediation (activates retry/breaker/bulkhead on every live
driver read/write/subscribe/discover), which must be its own verified change — exactly the discipline the
review espouses. So the sites were suppressed as a *tracked* gap (not "intentional"), keeping the tree
green and the analyzer live everywhere else, and this follow-up was filed.

## Proposed remediation

1. **Construct a per-`DriverInstance` `CapabilityInvoker`** and thread it into `DriverInstanceActor` (via
   its `Props`/ctor) and `GenericDriverNodeManager`. It needs:
   - the process-singleton `DriverResiliencePipelineBuilder`,
   - a `Func<DriverResilienceOptions>` options accessor (source the per-instance resilience options —
     confirm where they live / how Admin edits them),
   - the `driverType` string (already on the actor),
   - the `DriverResilienceStatusTracker` (so Admin `/hosts` shows in-flight/bulkhead depth),
   - the per-call host resolver (`IPerCallHostResolver`) for multi-host drivers.
2. **Route each of the 7 sites** through `ExecuteAsync` / `ExecuteWriteAsync` (writes/acks use the write
   variant). Remove the `RESILIENCE-DISPATCH-GAP` pragma at each site as it is wired.
3. **Fix `CapabilityInvoker`'s XML doc** once the claim becomes true.

## Verification bar (unit-green ≠ wired)

- **Unit:** an actor test asserting the capability call goes through a fake/recording invoker (not the raw
  driver). The analyzer itself becomes the standing guard — once the pragmas are gone, any regression that
  re-introduces a raw call fails the build.
- **Live (decisive):** on the docker-dev / driver rig, prove the pipeline is actually engaged — e.g. use
  the modbus `exception_injector` (see the write-outcome memory) or a flaky-read fixture to observe a retry
  / breaker-open transition and the `/hosts` in-flight counter moving. A behavior change on the live data
  path must not ship on unit tests alone.

## Decision needed

- Confirm this is worth doing now (it changes runtime latency/behavior on every driver call) vs. deferring.
- If deferring, keep the `RESILIENCE-DISPATCH-GAP` pragmas + this file as the standing record.
- Own branch off `master` (like the Criticals).