16 Commits
Author SHA1 Message Date
b409714731 Client: acknowledgement provider model and subscription acknowledgement fixes (#4899)
# Description

Fixes client subscription acknowledgement defects and replaces the
mutable event-based acknowledgement policy with an injectable,
asynchronous provider model. The latest changes in `7be912614` add
opt-in **whole-message delivery**, harden lifecycle/concurrency
behavior, and simplify acknowledgement state and wire-array
construction. Existing features and all deprecations remain in this PR.

The acknowledgement unit is one OPC UA `NotificationMessage`, not one
data change, event, downstream message, or group of Publish responses
indicated by `MoreNotifications`.

### Protocol and lifecycle fixes

- Ensure acknowledgements make progress when fewer acknowledgements are
queued than there are Publish workers.
- Honor legacy deferral on V2 and preserve deferred/in-flight
acknowledgements across retries. A throwing legacy callback restores the
original lists; a throwing provider defers the batch.
- Validate ownership before sending and after provider decisions,
including subscription removal, recreation, changed IDs and server ID
reuse. Reject detected responses from the previous owner before they
advance the replacement subscription's sequence cursor.
- Prune acknowledgements no longer retained by the server, including
servers without a retransmission queue.
- Retire one subscription's acknowledgement state without quiescing
publishing for the whole session.
- Reserve the classic engine's provider-decision slot before invoking
application code. Concurrent Publish calls cannot overwrite pending
decisions; asynchronous failures are observed and logged.
- Preserve the original outstanding lifecycle when a cancelled queue
attempt can still be queued. Retries do not create an additional
terminal outcome.
- Retire internal confirmation state synchronously, independently of
application observer progress. Observer callbacks remain asynchronous
and outside SDK locks.

### Public API and whole-message delivery

| API | Purpose |
|---|---|
| `AcknowledgementHandle` | Process-local acknowledgement identity
scoped to a subscription lifetime; avoids correlating messages solely by
subscription ID and sequence number. |
| `ISubscriptionAcknowledgementProvider` | Asynchronous, fail-closed
send/defer decisions over `ArrayOf<AcknowledgementHandle>`. |
| `ISubscriptionAcknowledgementObserver` | Terminal outcomes:
`Acknowledged`, `NotRetained`, `OwnerRetired`, or `Abandoned`, subject
to the cross-session limitation below. |
| `AcknowledgementMode.AfterConfirmation` /
`ISessionAcknowledgements.Confirm` | Do not acknowledge until the
application explicitly confirms processing of the complete message. |
| `ISubscriptionNotificationMessageHandler` /
`SubscriptionNotificationMessage` | Opt-in delivery of all typed
payloads in one envelope, preserving payload order, physical-partition
identity, publish time and diagnostic string table. |

- Provider configuration is available through `ManagedSessionOptions`,
fluent builder methods and DI registration.
- Whole-message handlers are registered through the V2 subscription APIs
or `Subscription.NotificationMessageHandler` on the classic engine.
Existing load/restore factories can return handlers implementing both
notification interfaces.
- Whole-message handling replaces data/event callbacks only for the
opted-in subscription; keep-alive and lifecycle handling remain
available. Returning from the handler does not implicitly confirm
delivery.
- Projection arrays do not borrow pooled wire notification containers.
Monitored-item references remain live SDK objects.
- Whole-message handlers receive shutdown cancellation before
subscription retirement waits for their dispatch to finish.
- Managed model-change tracking owns a dedicated whole-message
subscription instead of sharing application streaming acknowledgement
ownership. It confirms only after all events succeed; namespace-refresh,
cache-invalidation and subscriber failures remain logged but do not
produce a success confirmation.

### Compatibility and deprecations

The following deprecations remain, with compatibility behavior
preserved:

- `ISession.PublishSequenceNumbersToAcknowledge`: honored when no
provider is configured; not raised when a provider owns the policy.
- Classic `FastDataChangeCallback`, `FastEventCallback`,
`FastKeepAliveCallback` and their delegate types.
- `ISession.DefaultSubscription` and its implementations.

The lifetime proposal from the closed PR #4901 is incorporated through
the provider/handle model rather than additional lifecycle events.

### Simplification and performance scope

- Pending acknowledgements derive owner and generation from their scope
rather than storing redundant copies.
- Wire acknowledgements are projected directly into the final array,
eliminating the intermediate converted list and its extra copy.
- Whole-message envelopes are constructed only for opted-in handlers.
The existing payload-callback path remains available.
- Handles reuse cached subscription-lifetime scopes. Provider callbacks
execute outside SDK locks.

This is not a benchmarked throughput or allocation-parity claim. Broader
lock/contention work, provider-path allocations and benchmark evidence
remain tracked by #4912.

### Known limitations and non-goals

- **#4929 remains open:** classic subscriptions served by the default V2
compatibility bridge do not yet participate in normal acknowledgement
tracking. Supporting the classic engine is not the same as fixing that
bridge.
- **#4930 remains open:** transferring a classic subscription between
different `Session` objects does not yet move tracked
acknowledgements/confirmations between engines. Duplicate terminal
reports or lost confirmations remain possible on that path. In-place
managed-session recreation is a different, supported path.
- Delaying protocol acknowledgement is not itself downstream retry or
durable storage. Applications still own downstream retry/buffering;
server retransmission queues are finite.
- External observer delivery is buffered. Slow observers can grow their
notification backlog, although they no longer retain internal
confirmation state. Disposal waits up to five seconds for callbacks; an
unresponsive observer can outlive disposal.
- HA takeover/session-continuation redesign and server-side
acknowledgement defects are not addressed here.

Documentation: [Subscriptions](docs/Subscriptions.md), [Migration
guide](docs/MigrationGuide.md), and [Model-change
tracking](docs/ModelChangeTracking.md).

### Validation

Local validation of the changes included in `7be912614`:

| Check | Result |
|---|---|
| Expanded net10 client regression selection | **389 passed, 0 failed, 0
skipped** |
| Final API-registration and whole-message-routing selection | **3
passed**; two overlap the regression selection, one is additional (**390
distinct client cases across the runs**) |
| Acknowledgement integration tests | **4 passed**: classic/V2, each
with legacy payload callbacks and whole-message handling |
| `Opc.Ua.Client` net48 build | **0 warnings, 0 errors** |
| Scoped whitespace, style and analyzer verification | Passed, including
informational severity for style/analyzers |
| Negative/revert controls | Tests reproduced the provider race, missing
whole-message routing, observer-dependent cleanup, cancelled-queue
lifecycle loss, shutdown deadlock and false model-change confirmation;
corrections were restored and positive cases passed |

<details>
<summary>Exact local test/build commands and results</summary>

Run from the repository root. Framework-specific assets must be restored
before commands using `--no-restore`; perform the net48 build last
because changing `CustomTestTarget` replaces restored assets.

```powershell
dotnet test tests\Opc.Ua.Client.Tests\Opc.Ua.Client.Tests.csproj -p:CustomTestTarget=net10.0 --framework net10.0 --no-restore --filter "FullyQualifiedName~AcknowledgementProviderTests|FullyQualifiedName~SubscriptionManagerTests|FullyQualifiedName~ClassicSubscriptionEngineTests|FullyQualifiedName~ManagedSessionAcknowledgementForwardingTests|FullyQualifiedName~AcknowledgementOptionsTests|FullyQualifiedName~SubscriptionTests|FullyQualifiedName~ModelChangeTrackerTests|FullyQualifiedName~PartitionForwardingHandlerTests|FullyQualifiedName~SessionEngineContextTests|FullyQualifiedName~DefaultSubscriptionEngineTests|FullyQualifiedName~MonitoredItemManagerTests|FullyQualifiedName~MessageProcessorTests" --logger "console;verbosity=minimal" -v quiet -nologo
# Passed: 389; failed: 0; skipped: 0.

dotnet test tests\Opc.Ua.Client.Tests\Opc.Ua.Client.Tests.csproj -p:CustomTestTarget=net10.0 --framework net10.0 --no-restore --filter "FullyQualifiedName~WholeMessageRegistrationRejectsMissingInputs|FullyQualifiedName~WholeMessageDeliveryPreservesMixedPayloadsAsync" --logger "console;verbosity=minimal" -v quiet -nologo
# Passed: 3; failed: 0; skipped: 0. Two cases overlap the previous selection.

dotnet test tests\Opc.Ua.Subscriptions.Tests\Opc.Ua.Subscriptions.Tests.csproj -p:CustomTestTarget=net10.0 --framework net10.0 --no-restore --filter "FullyQualifiedName~AcknowledgementProviderIntegrationTests" --logger "console;verbosity=minimal" -v quiet -nologo
# Passed: 4; failed: 0; skipped: 0.

dotnet build src\Opc.Ua.Client\Opc.Ua.Client.csproj -p:CustomTestTarget=net48 -p:RestoreSources=https://www.nuget.org/api/v2/ -p:NuGetAudit=false -v quiet -nologo
# Build succeeded: 0 warnings, 0 errors.
```

The v2 feed and disabled NuGet audit above were local restore
workarounds only; repository settings were not changed. CI dependency
auditing remains required.

</details>

The full `UA.slnx` net48/net10 test matrix, NativeAOT publishing/runtime
validation, fresh coverage measurements and performance benchmarks were
**not run locally for this revision**. CI and maintainer API review
remain outstanding. Historical results on `a28c12252` are not presented
as validation of the latest head.

## Related Issues

_If this is a relatively large or complex change, a design must have
been discussed in the related tracking issue and signed off (which
becomes the Architectural Decision Record (ADR))._

- Fixes #4894: acknowledgement progress, deferral/retry behavior and
ownership validation.
- Fixes #4898: injectable fail-closed decision API, with legacy
precedence preserved.
- Fixes #4913: admission of detected old-owner responses after
subscription ID reuse.

Non-closing references:

| Issue | Title / scope | Disposition |
|---|---|---|
| [#4897](https://github.com/OPCFoundation/UA-.NETStandard/issues/4897)
| Stable notification identity and terminal acknowledgement state | Core
functionality is implemented via handles/providers, with whole-message
delivery added. Keep this link non-closing until the cross-session
exception in #4930 is resolved or the issue's accepted scope is
explicitly narrowed. |
| [#4912](https://github.com/OPCFoundation/UA-.NETStandard/issues/4912)
| Reduce acknowledgement-path lock contention and allocations |
Partially advanced by state/projection simplification; broader locking
changes and benchmarks remain. |
| [#4929](https://github.com/OPCFoundation/UA-.NETStandard/issues/4929)
| Classic subscriptions on the V2 compatibility bridge | Not fixed;
separate follow-up. |
| [#4930](https://github.com/OPCFoundation/UA-.NETStandard/issues/4930)
| Cross-session classic acknowledgement handover | Not fixed; separate
follow-up and explicit limitation on terminal-outcome guarantees. |

Design rationale: [maintainer request for injectable providers and
session
facets](https://github.com/OPCFoundation/UA-.NETStandard/pull/4899#discussion_r4366515418).
The new whole-message API is submitted for maintainer review; this
description does not claim that its final API shape or an ADR has been
signed off.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

Regression tests were added and passed; the combined tests/coverage
checkbox is left open because a fresh coverage increase has not yet been
verified.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
Co-authored-by: Marc <marcschier@hotmail.com>
2026-10-28 13:55:20 +00:00
Wolfgang ColsmanandMarc Schier be9ccf912c Client: evaluate the durable subscription lifetime on every physical create (#4882)
# Description

## Problem

`ISubscription.SetAsDurableAsync(TimeSpan lifetime, CancellationToken
ct)` marks a subscription durable with the Server method
`SetSubscriptionDurable` (OPC 10000-5, "SetSubscriptionDurable Method";
OPC 10000-4, "Durable Subscriptions"). `SetSubscriptionDurable` must be
called before the subscription has monitored items; a conforming server
rejects it afterwards with `Bad_InvalidState`.

`LogicalSubscription` stores the `TimeSpan` and installs an
`OnAfterCreateAsync` hook on each partition. The partition state machine
runs the hook after every `CreateSubscription` and before the first
`CreateMonitoredItems`, so durability survives every later physical
create:

- recreate after a service call reports `BadSubscriptionIdInvalid`
(`Subscription.ApplyStateChangesAsync` → `ResetToRecreateAsync`),
- recreate after `TransferSubscriptions` fails on session recreate
(`SubscriptionManager.RecreateSubscriptionsAsync` → `RecreateAsync`) or
on load (`RestoreTransferAsync` → `ResetToRecreateAsync`),
- recreate after a status-change timeout or an unsolicited
`Good_SubscriptionTransferred`,
- a new secondary partition (`TryApplyDurableToNewPartition`).

The hook always re-applies the lifetime fixed by the first call. An
application whose durable lifetime must not exceed a bound that shrinks
over time (for example an authorization or retention window that ends at
a known instant, after which the server must no longer queue
notifications) cannot keep that bound after a recreate, and it has no
way to supply a new value at the right moment:

- calling `SetAsDurableAsync` again after the recreate is rejected once
monitored items exist;
- `ISubscriptionNotificationHandler.OnSubscriptionStateChangedAsync` is
dispatched fire-and-forget, so a call made from it can arrive after the
first `CreateMonitoredItems`;
- `SubscriptionOptions` has no durable setting and `OnAfterCreateAsync`
is internal.

## API

```csharp
namespace Opc.Ua.Client.Subscriptions
{
    public interface ISubscription
    {
        // existing
        ValueTask<TimeSpan> SetAsDurableAsync(TimeSpan lifetime, CancellationToken ct = default);

        // new
        ValueTask<TimeSpan> SetAsDurableAsync(Func<TimeSpan?> lifetime, CancellationToken ct = default);
    }
}
```

## Behaviour

- The provider is evaluated once for the call itself; the value is sent
to every partition that is already created (unchanged: the call returns
the minimum revised lifetime of those partitions, or the requested value
when none is created yet).
- The provider is stored and evaluated again by the existing
after-create hook before every later physical create, between
`CreateSubscription` and the first `CreateMonitoredItems` of that
create.
- A `null` result requests no durability for that create: no
`SetSubscriptionDurable` is sent and the recreated subscription is a
regular one. A `null` result for the call itself returns `TimeSpan.Zero`
without contacting the server.
- An exception thrown by the provider during a later create is handled
exactly like a rejected `SetSubscriptionDurable` call today: the state
machine logs a warning, reports `SubscriptionState.Modified`, and the
subscription continues (its monitored items are created). An exception
during the call itself propagates to the caller.
- `SetAsDurableAsync(TimeSpan)` now forwards to `SetAsDurableAsync(() =>
lifetime)`; its behaviour is unchanged.
- `docs/Subscriptions.md` describes the provider and corrects the
statement that the hook is cleared after invocation (on master it stays
installed).

Not included: a notification reporting the outcome (revised lifetime or
status) of each re-applied `SetSubscriptionDurable`. Today a failed
re-apply is only logged and surfaced as `SubscriptionState.Modified`;
this could be a follow-up if maintainers want it.

## Tests

New tests in
`tests/Opc.Ua.Client.Tests/Subscription/SubscriptionTests.DurableLifetime.cs`
drive a real partition (`Subscription`) behind
`SubscriptionManager`/`LogicalSubscription` against mocked services and
record `CreateSubscription`, `SetSubscriptionDurable` (requested hours),
`CreateMonitoredItems`, `TransferSubscriptions` and
`DeleteSubscriptions` in call order. The provider returns 10 h for the
initial call and 7 h afterwards:

-
`DurableLifetimeProviderIsEvaluatedOnRecreateAfterSubscriptionIdInvalidAsync`:
`ModifySubscription` returns `BadSubscriptionIdInvalid`; the recreate
sends 7 h between `CreateSubscription` and the first
`CreateMonitoredItems`.
-
`DurableLifetimeProviderIsEvaluatedOnRecreateAfterFailedTransferAsync`:
`TransferSubscriptions` on session recreate returns
`BadSubscriptionIdInvalid`; delete, create, 7 h, items.
- `DurableLifetimeProviderIsEvaluatedForNewPartitionAsync`:
`MaxMonitoredItemsPerPartition = 1`; the second item mints a partition
that sends 7 h before its items.
-
`DurableLifetimeProviderReturningNullSendsNoSetSubscriptionDurableAsync`:
provider returns `null` on recreate; no `SetSubscriptionDurable`, items
are created.
-
`DurableLifetimeProviderThatThrowsLeavesRecreatedSubscriptionRunningAsync`:
provider throws on recreate; no `SetSubscriptionDurable`, items are
created, subscription stays created.
- `DurableFixedLifetimeIsReappliedOnRecreateAsync`: regression of the
`TimeSpan` overload (10 h again on recreate).

Unit tests in `LogicalSubscriptionTests`:
`SetAsDurableWithProviderEvaluatesItOnceForAllCreatedPartitionsAsync`,
`SetAsDurableWithProviderReturningNullSendsNothingAsync`,
`SetAsDurableWithNullProviderThrowsAsync`.

Negative control: with the hook evaluating the provider once at
installation (the previous fixed-value behaviour), the
recreate-after-`BadSubscriptionIdInvalid`, failed-transfer, null and
throwing-provider tests fail (4 of 10).

Local results (Windows, .NET SDK 10.0.402, Release):

| Run | Result |
| --- | --- |
| `Opc.Ua.Client` build, net48/net8.0/net9.0/net10.0 | 0 warnings, 0
errors |
| `SubscriptionTests` + `LogicalSubscriptionTests`, net10.0 | 105/105
passed |
| `SubscriptionTests` + `LogicalSubscriptionTests`, net48 | 105/105
passed |
| `Opc.Ua.Client.Tests`, namespace `Opc.Ua.Client.Subscriptions`,
net10.0 | 353/353 passed |
| `Opc.Ua.Subscriptions.Tests` `SubscriptionManagerCoverageTests` +
`StreamingSubscriptionCoverageTests`, net10.0 | 72/72 passed |
| `Opc.Ua.Subscriptions.Durable.Tests` `SubscriptionDurableTests` +
`DurableSubscriptionTest*` (in-process reference server with durable
subscriptions enabled), net10.0 | 21/21 passed |

## Related observation (not changed here)

A secondary partition minted by `SubscriptionManager.Add`'s partition
factory starts its state machine in the `Subscription` constructor,
before the factory calls `TryApplyDurableToNewPartition`. When
`CreateSubscription` completes before the factory returns (observed with
a synchronously completing mock), `RunAfterCreateHookAsync` finds no
hook and the new partition is created without `SetSubscriptionDurable`,
for the `TimeSpan` overload as well. With a real round trip the hook is
installed first;
`DurableLifetimeProviderIsEvaluatedForNewPartitionAsync` therefore holds
the secondary's `CreateSubscription` response until the factory has
returned. Installing the hook before the partition's first state-manager
pass would remove the window.

## Compatibility

- Source and binary compatible for callers of `ISubscription`.
- `ISubscription` gains a member. Custom implementations of the public
interface (outside the stack; the stack's own implementations are
internal) must add the overload; a default interface implementation is
not possible because the library also targets .NET Framework 4.8. The
three test doubles in the repository were updated.
- No wire, configuration or server change.

## Related Issues

- Independent of #4881; with #4881 the lifetime provider is also applied
to a new partition that is created before the partition factory returns.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed. (Run
locally: the affected test classes on net48 and net10.0 and the whole
Opc.Ua.Client.Tests project on net10.0; not the whole UA.slnx.)
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

---------

Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
2026-10-22 18:51:01 +02:00
Wolfgang Colsman 00479792ae Client: install the durable hook before a new partition creates itself (#4881)
# Description

## Defect

`LogicalSubscription.SetAsDurableAsync(TimeSpan)` records the durable
lifetime and installs an
`OnAfterCreateAsync` hook on every partition, so that
`SetSubscriptionDurable` (OPC 10000-5) is
called between `CreateSubscription` and the first `CreateMonitoredItems`
of each physical create,
as OPC 10000-4 requires for durable subscriptions.

A secondary partition minted on demand (when the logical subscription
exceeds
`MaxMonitoredItemsPerPartition`) starts its state machine inside its
constructor. The partition
factory in `SubscriptionManager` installed the hook only after the
constructor returned
(`TryApplyDurableToNewPartition`). When the server answered
`CreateSubscription` before the factory
returned, the create pass read no hook, the partition was created
without `SetSubscriptionDurable`,
and its monitored items were created on a non-durable subscription. The
hook only runs after a
create, so it never ran for that partition; a later
`SetSubscriptionDurable` is refused by a
conforming server once items exist (`Bad_InvalidState`). The outcome
depended on timing.

## Reproduction


`SubscriptionTests.DurableIsSetOnNewPartitionCreatedBeforeFactoryReturnsAsync`:
a mocked server
answers every call immediately, `MaxMonitoredItemsPerPartition = 1`, the
logical subscription is
made durable for 10 h, and the partition factory returns only after the
new partition reports
`Created`. Result on `master` (bc97bf720):

```
Expected: < "create:22", "durable:22:10h", "items:22", "create:23", "durable:23:10h", "items:23" >
But was:  < "create:22", "durable:22:10h", "items:22", "create:23", "items:23" >
```

## Fix

The partition is now wired before its state machine starts:

- `Subscription` (internal) constructor takes an optional
`Action<IManagedSubscription> initialize`
  and invokes it immediately before starting the state machine.
- `ISubscriptionManagerContext.CreateSubscription` (internal) takes the
same optional callback and
must run it before the first create pass; `DefaultSubscriptionEngine`
forwards it to the
  constructor.
- `SubscriptionManager` passes an initializer for on-demand secondary
partitions (both the
`Add` and the transfer-restore paths) that attaches the reactive
fallback and the durable hook,
  which it previously did after the factory returned.

The hook itself, `LogicalSubscription`, the primary and
preloaded-partition paths are unchanged.

## Tests

- New: `DurableIsSetOnNewPartitionCreatedBeforeFactoryReturnsAsync`
(fails on `master`, passes) and
`InitializeRunsBeforeTheFirstCreatePassAsync` (initializer runs while
the subscription is not yet
created and a hook installed there runs after the first
`CreateSubscription`).
- Test fakes implement the new parameter;
`FakeSubscriptionManagerContext` gains
`CreateInitializedSubscriptionFactory` and otherwise runs the
initializer after its factory, as
  before.
- Regression: `SubscriptionTests`, `LogicalSubscriptionTests` (net10.0
and net48), the
  `Opc.Ua.Client.Subscriptions` namespace of `Opc.Ua.Client.Tests`,

`SubscriptionManagerCoverageTests`/`StreamingSubscriptionCoverageTests`,
and the durable
integration tests (`SubscriptionDurableTests|DurableSubscriptionTest`).

Results (Release, commit 4250c2556): focused classes net10.0 98/98 and
net48 98/98,
`Opc.Ua.Client.Subscriptions` namespace net10.0 346/346, coverage tests
72/72, durable
integration 21/21; the two new tests passed 20 of 20 repeated runs.
`Opc.Ua.Client` builds for
net10.0, net9.0, net8.0 and net48 with 0 warnings and 0 errors; `dotnet
format` whitespace and
style report no changes for the changed files.

## Interaction with the durable lifetime provider branch

`git merge-tree --write-tree` against
`feature/durable-lifetime-provider` reports no conflicts. That
branch changes `InstallDurableHook` and `TryApplyDurableToNewPartition`
but not their call site; with
this fix its provider-based hook is also installed before a new
partition's first create.

## Compatibility

No public API change. `Subscription` and `ISubscriptionManagerContext`
are internal; the new
parameters are optional and last. Behaviour is unchanged except that the
reactive fallback and the
durable hook of a new partition are in place before its first create
pass.

## Related Issues

- No tracking issue; the problem and the design are described above.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [ ] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed. (Run
locally: the affected test classes on net48 and net10.0 and the whole
Opc.Ua.Client.Tests project on net10.0; not the whole UA.slnx.)
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.
2026-10-22 12:59:43 +00:00
Marc Schier 0374e19121 Add MachineTool, WMTP, GMS and CranesHoists companions (#4765)
# Description

_Describe the changes here to communicate to the maintainers why they
should accept this pull request. By default - this will become the
Commit message after merging and thus define history._

Add provider-backed MachineTool, bundled WMTP, GMS and CranesHoists
companions using the existing Machinery/MachineVision fluent, DI and
typed-client approach. **The PR is open/non-draft by user choice.
Current head `ecc4a7d6ca3e8004cf28ab54da605da302d026bf` is mergeable and
has 108 successful checks, six intentionally skipped checks, zero
failures and zero pending checks. All five primary workflows completed
successfully at that exact head.**

| Family | Released specification/model | Packaging |
| --- | --- | --- |
| MachineTool | OPC 40501-1, 1.02.0 | Model, Server, Client and MCP;
normal root versions |
| WMTP | OPC 40505, 1.0.0 | Bundled in MachineTool; distinct CLR/wire
namespace and independent WMTP-only hosting |
| GMS | OPC 40210 reference 1.0.1, normative model 1.0.0 | Model,
Server, Client and MCP; normal root versions |
| CranesHoists | OPC 40020-1, 1.00 | Model, Server, Client and MCP; all
four plus Debug variants forced preview |

There are **12 new packable projects**. No separate WMTP
package/profile/guide, root version bump, tag, release or package
publication is included. Mandatory instance structure is the default;
selected optional features require explicit providers. The
implementation reuses Machinery results/jobs/files/ProcessValues and
Robotics topology, including retained MachineTool Production, defined
GMS jobs/parts, modern ISA95/Machinery jobs, shared-owner hosting and
isolated instances alongside MachineVision.

Runtime and integration fixes preserve raw quality/timestamps, coherent
acquisition, namespace ownership, accepted-configuration state,
borrowed-resource lifetime, session/node/file cleanup, terminal-value
publication, event propagation and endpoint-aware capability
publication. Firmware/licence transfer means provider acceptance, not
installation/activation. Cancellation does not silently abort another
caller's operation. The later upstream MCP expansion is integrated
without losing either family set or its default-off privileged/live
execution policy.

### Conformance and scope

Canonical model inputs are pinned to UA-Nodeset revision
`96a08945425d0295edb3607d2a38f6841ef44046`.

**GMS upstream exception:** [Annex
A.1](https://reference.opcfoundation.org/specs/OPC-40210/annex-a) makes
the released NodeSet normative, but §12.3.2.7 requires undefined
`GMS_ProductionStatisticsType`. Inherited statistics and defined
jobs/parts are implemented without inventing a standard type/NodeId; the
complete GMS Production facet is withheld.

The requirement ledger records **102 positively evidenced CU rows, 96
directly negative-tested rows and six explicit negative-evidence
limitations**. All 648 test-class/name/TRX links were independently
resolved to passing cases. The six limitations concern Stacklight,
retained legacy PowerOnDuration, Machinery PowerOnDuration, WorkingUnit,
Obligation and MaintenanceMode. They are not claims that every
invalid-input or hardware-control behavior was tested. The undefined GMS
requirement is outside the 102 defined CUs. No external certification
claim is made.

Retained baseline complete-assembly line coverage, with generated code
retained and no source exclusions:

| Family | Model | Server | Client |
| --- | ---: | ---: | ---: |
| MachineTool/WMTP | 83.80% | 91.98% | 84.74% |
| GMS | 95.51% | 90.63% | 88.38% |
| CranesHoists | 92.76% | 94.45% | 92.24% |

These nine measurements predate the later focused review fixes and
merges; they are not relabelled as new `ecc4a7d6c` percentages. The
current head's separate CI code-coverage check succeeded. No new
exclusions or threshold relaxations were introduced.

## Related Issues

- Fixes
[#4764](https://github.com/OPCFoundation/UA-.NETStandard/issues/4764),
the implementation/design and acceptance tracker.

## Checklist

_Put an `x` in the boxes that apply. You can complete these step by step
after opening the PR._

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [ ] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
2026-10-15 15:15:46 +02:00
romanettandClaude Opus 5.5 9b034f8291 Enable nullable reference types centrally; migrate all unset and annotations-only projects (#4700)
# Description

Nullable reference types are now enabled once, in `common.props`, and
every project in the repository builds warning-clean with them.

**Configuration**
- `<Nullable>enable</Nullable>` lives in `common.props`. All per-project
`<Nullable>` settings are removed: 178 project files (enable,
annotations, and the `disable` in the three Aot test projects).
- 419 per-file `#nullable enable`/`restore` directives and the 4
`#nullable disable` directives are removed.
- Kept on purpose:
- The 5 `<auto-generated>` schema files (`UANodeSet.cs`, `UA Type
Dictionary.cs`, `OPCBinarySchema.cs`, `SecuredApplication.cs`,
`PInvokeHelper.cs`) keep `#nullable enable`. The compiler ignores the
project setting in generated code, so the directive is required there.
- `tests/Opc.Ua.Interop.LegacyPeer` keeps `disable`. It builds against
the 1.5.378 packages and does not import the repository props.
- `docs/DeveloperGuide.md` and `.github/copilot-instructions.md` now
describe the central setting.

**Migration** (the 43 unset and 13 annotations-only projects, roughly
10k diagnostics)
- **Production code: annotated at the declarations.** Covers
`tools/Opc.Ua.SourceGeneration.Core`, `src/Opc.Ua.Lds.Server` and the
LDS sample.
- Members, parameters and returns are nullable where null actually
flows.
- Null-check helpers carry `[NotNullWhen]` (`IsNull`, `IsValidXmlName`,
`IsMethodTypeDesign`).
- `CoreUtils.Format`, `Utils.Format`, `ITemplateWriter.WriteLine` take
`params object?[]`. `Template.AddReplacement` takes `string?` (rendering
already skips null replacements).
- `IRegisteredServerStore.RegisterAsync` returns
`Task<RegistrationEntry?>`: it returns null when a registration is
removed.
- Dereferences backed by an invariant (for example, the validated model)
use `!`, so runtime behaviour is unchanged.
- **Behavioural changes in production code** (small, deliberate):
- `NodeSetToModelDesign` throws `InvalidOperationException` when the
file is not a NodeSet. Before, it threw a NullReferenceException on the
next line.
- `ModelDesignValidator` starts its lookup tables empty instead of null.
A redundant `if (m_nodes == null) return;` guard is gone.
- **Test code: minimal annotations.**
  - `?` on values that can be null, `!` where the test asserts non-null.
  - `= null!` for fixture members assigned in SetUp.
- `TryGetStructure<T>(out T? x)` where the inferred `T?` broke the
`IEncodeable` constraint.
- A few redundant `== null` checks on structs (`NodeId`, `ArrayOf<T>`)
folded into the adjacent `IsNull`/`Count` checks.

**Notes for reviewers**
- The diff is large (~1,500 files) but almost entirely mechanical: `?`,
`!` and directive removal. The non-annotation changes are listed above.
- Known follow-up, not done here:
`IModelDesign.Namespaces/TargetNamespace/NamespaceUris` stay
non-nullable even though the validator returns null before it loads a
dictionary. Making them nullable would ripple through every generator
call site.

## Related Issues

- Fixes #4439

## Checklist

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [ ] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

The "no new warnings" box covers net10.0 and net48: full non-incremental
builds of `UA.slnx`, `tools/SourceGeneration.slnx`,
`tools/MigrationAnalyzer.slnx` and the Aot test projects finished with 0
warnings and 0 errors under the repository's warnings-as-errors
settings. net9.0 and net8.0 also had no nullable diagnostics, but they
were not rebuilt after the final fixes. Tests have not been run locally
yet.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-08 08:48:13 +02:00
87c35b84b6 Fix Opc.Ua.Client audit findings (security fallback, reconnect, subscriptions, redundancy, browse, files, WebApi) (#4572)
## Summary

Fixes the findings of a bug audit of `Opc.Ua.Client` and
`Opc.Ua.Client.ComplexTypes`, done on master plus #4516 (now merged).

- **Audit:** 82 findings across 12 areas, each checked against the OPC
UA specification. Final severities: 2 High, 37 Medium, 43 Low.
- **Fixes:** 76 fixed, 4 partial, 2 skipped (see [Not
fixed](#not-fixed--partial)).
- **Review:** a follow-up review of the fixes found 15 more defects in
them, all fixed here.
- **Tests:** every fix has a regression test, except a few races that
cannot be reproduced deterministically; the commit messages say which.

The finding IDs (`L<area>-<n>` for the audit, `G<n>` for the review)
appear in the commit titles.

## Behaviour and user-facing changes

### Security and endpoint selection
- **Reconnect no longer drops to weaker security (L3-1, High).** When
the server rejects the configured security policy or mode during
reconnect, `SessionReconnectHandler` no longer switches to whatever
endpoint the server advertises, None included. It only picks an endpoint
at least as strong as the configured one, judged by a locally computed
security level. The server-advertised `SecurityLevel` is not trusted. If
nothing qualifies, reconnect fails with the original error (new log
event `SessionReconnectHandler + 13`) and keeps retrying with the
original settings.
- **`CoreClientUtils.SelectEndpoint(useSecurity: true)` never returns a
SecurityMode None endpoint over opc.tcp (L9-9, High).** It now returns
`null` when no secure endpoint matches.
- When the discovery URL is `https`/`opc.https`, an HTTPS endpoint with
SecurityMode None is still accepted as a last resort, because TLS
protects it (Part 6 §7.4.1) (G17).
  - Endpoints with SecurityMode `Invalid` no longer count as secure.
- `GlobalDiscoveryServerClient` and `ServerPushConfigurationClient` now
throw `BadSecurityPolicyRejected` when no secure endpoint matches,
instead of passing `null` on. The ConsoleReferenceClient sample reports
this with a clear error.
- **No Bearer/Basic credentials over `http://` (L12-2).**
`WebApiClient.Create` and WebApi channel open/reconnect reject them with
`BadSecurityChecksFailed`. The public `WebApiClient(HttpClient, …)`
constructor also rejects them when the client's `BaseAddress` is not
https, and every send checks the address it actually goes to (covers a
`BaseAddress` set later).

### Session, keep-alive and identity
- **Faster detection of a silent server (L1-1).** The keep-alive Read is
now bounded by its `TimeoutHint` (2 × `KeepAliveInterval`), which is
what Part 4 §7.32 says the client should do. It then fails with
`BadNoCommunication`, so reconnect starts after about 2 ×
`KeepAliveInterval` instead of `OperationTimeout` (120 s by default).
- **Operations fail fast during a channel-manager recovery (L1-2, G9).**
`UpdateIdentityAsync`, `TransferSubscriptionsAsync` and
`ReactivateSubscriptionsAsync` fail with `BadSecureChannelClosed`
(retryable) instead of deadlocking. This covers the operation holding
the reconnect lock and any queued behind it.
- **Closing or disposing from a handler no longer waits on itself (L1-3,
G5, G6).**
- `Session` and `ManagedSession` Close/Dispose from a Notification
handler no longer wait 30 s for their own background drain.
- Disposing a `ManagedSession` from a keep-alive `PublishStatusChanged`
handler no longer deadlocks.
- Tasks spawned by a handler no longer count as "the handler" (the owner
marker is scoped to the work item).
- **Switching to an ECC user-token policy takes two ActivateSession
calls (L1-4, G4).** This follows Part 6 §6.8.2 (fetch the ephemeral key,
then activate).
- If the server returns no key, the switch fails with
`BadSecurityPolicyRejected`.
- If the second activation is rejected, the old identity stays on the
override policy with the key just fetched. Restoring the old key was
tried: against the reference server the next reconnect then failed to
decrypt the identity token.
- **`ManagedSession.ConfiguredEndpoint` follows failover (L2-6).** It
now reports the inner session's endpoint, so it changes after a failover
or network-path rotation.
- **An explicit identity update replaces the identity provider (L2-7).**
`ManagedSession.UpdateSessionAsync(identity)` stops the provider's
refresh loop and drops the provider for good. If the update fails, the
loop is restarted.
- **Reconnect waits for in-flight calls on a healthy channel (L2-3,
G8a).** Reconnect/failover on a healthy channel (certificate or
trust-list change, manual reconnect) waits for in-flight service calls.
The wait is bounded (max(`KeepAliveInterval`, 1 s)) only once the
channel is unhealthy (keep-alive stopped, channel not Ready), so a dead
channel no longer holds recovery for `OperationTimeout`.
- **Smaller fixes:**
- Restore reads the server certificate as a chain; this failed on macOS
(L1-5).
  - Session recovery can no longer run twice at once (L1-6).
  - Identity expiries more than 49.7 days out no longer throw (L2-2).
- Keep-alive reconnect suppression is recalculated on a lease swap
(L2-4).

### Reconnect state machine and reverse connect
- **⚠ `MaxTotalReconnectTime = 0` now means "no time limit" (L3-7).
Reviewer decision needed.** Before, 0 disabled reconnect entirely.
Negative values other than `Timeout.InfiniteTimeSpan` now throw
`ArgumentOutOfRangeException` when the state machine is constructed;
before, they crashed the worker. The XML docs of
`ReconnectPolicy`/`ReconnectPolicyOptions` are updated. If 0 should keep
meaning "no reconnect", this is a one-line revert.
- **A close racing the end of the reconnect budget is no longer lost
(L3-4).** It goes through the normal close instead of switching to
failover.
- **The "reconnect worker" marker covers one step only (L2-1).** It
lasts for a single connect/reconnect/failover/close step. Keep-alive,
publish and identity loops started in a step no longer count as the
worker afterwards.
- **Reverse-connect strategies `Undefined` and `Any` alone are removed
after the first callback (L8-1).** This matches the documentation;
before, they behaved like `Always`.
- **`AddEndpoint` for a URL that is already added disposes the replaced
listener (L8-2).**

### Service calls
- **Batched calls clean up after a failed later batch (L3-2).** When a
later batch of
`Browse`/`BrowseNext`/`HistoryRead`/`CreateMonitoredItems` fails, the
continuation points and monitored items created by earlier batches are
released or deleted before the exception is rethrown. This adds one
request. `AddNodes`/`RegisterNodes` are not undone.
- **Batched diagnostic infos point at the right strings (L3-3).** The
string-table indexes are rebased when diagnostics are padded.
- **`ReadBytesAsync` rejects oversized responses (L3-5).** It throws
`BadUnknownResponse` when the server returns more bytes than requested,
and `BadEncodingLimitsExceeded` beyond `int` range.
- **`ReadByteStringInChunksAsync` handles an unknown server limit
(L3-6).** When the server's `MaxByteStringLength` is 0 (absent) or
larger than `int`, it falls back to the client's
`MessageContext.MaxByteStringLength`. It throws only when both are
unknown.

### Browse and NodeCache
- **Empty browse pages with a continuation point are followed (L9-1,
L9-4, L9-5, G16).** Part 4 §5.9.2.1 allows a server to return an empty
page with a continuation point, so browsing keeps following it. After 10
consecutive empty rounds it gives up with `BadNoData` and releases the
continuation point.
- `BrowseAsync(NodeId)` now throws instead of silently returning a
truncated list.
  - `BrowseStreamAsync` yields a `BadNoData` result for that node.
- The same cap, through one shared helper, now also protects
`RoleManagementClient.ListRolesAsync` and the FileSystem
enumerate/empty-check loops.
- **Continuation points are released on failure (L9-3).**
`BrowseAsync(NodeId)` releases them on any exception, and
`BrowseStreamAsync` releases all points of the current page when the
consumer stops early.
- **NodeCache lookups propagate cancellation (L9-6, L9-8).**
`FindAsync`, `IsKnownAsync`, `FetchNodeAsync`,
`FindReferenceTypeNameAsync`, the reference-table fill and the
type-hierarchy search now let `OperationCanceledException` through.
Before, a cancelled lookup looked like "node does not exist".
- **A NodeClass mismatch fails only that node (L9-7).** It returns
`BadNodeClassInvalid` for that node instead of throwing
`KeyNotFoundException` for the whole batch.
- **Smaller fixes:**
- `MaxNodesPerBrowse` ≥ 2^31 no longer breaks the managed browse (L9-2).
  - Null discovery URLs are skipped (L9-10).
  - `ModelChangeTracker` no longer cancels a joined start (L9-11).
- **Log changes:** `BrowserContinuationPointExistsButBrowse` (Browser +
0) was removed, and `BrowserServerReturnedEmptyReferencesBut` now
includes the round count.

### Subscriptions (default engine)
- **Recovery after a transfer delivers each message exactly once (L5-1,
G22).** Messages already dispatched are acknowledged instead of
republished and delivered again. Messages whose earlier republish failed
are now republished and delivered, with the Republish flag and after
newer messages, instead of being acknowledged and lost.
- **A keep-alive that proves a gap triggers republish at once (L5-5,
G23).** The dedup mark moves only past messages that were actually
recovered, so a failed republish is retried by the next data message.
- **Item changes that fail are retried with backoff (L5-3).** They are
retried on the next apply pass after the state manager's 250 ms–5 s
backoff, instead of six times back to back. The six attempts now span
about 13 s.
- **Extreme revised intervals no longer throw (L5-4, L6-1).** Very large
or NaN intervals and counts revised by the server are capped (NaN falls
back to the requested value). Before, the overflow could stop every
publish worker.
- **`SetTriggeringAsync` from a callback no longer hangs (L5-7, G21).**
While the subscription is deleted, recreated or disposed, it returns
`BadOperationAbandoned`. A cancelled reset no longer makes later calls
fail.
- **Publish responses for unknown subscription ids (L6-3, L6-4, G20).**
The client no longer re-sends acknowledgements the server already
processed. An unknown id seen while a creation is pending is left alone
instead of being deleted.
- **Smaller fixes:**
- A null and an empty `IndexRange` are treated as equal, and restored
snapshots use `null` (L5-6).
  - A failed partition attach during restore is rolled back (L6-2).
- `StreamingSubscription` throws `ObjectDisposedException` after dispose
(L6-6).

### Subscriptions (classic `Subscription`)
- **Republish no longer abandons other missing messages (L7-1).** A
Republish response no longer overwrites `AvailableSequenceNumbers`, so
other missing messages are not given up while the server still holds
them.
- **Late copies are no longer delivered twice (L7-2).** Copies of
already-processed sequence numbers are ignored, and creating a new
server subscription resets the sequence state.
- **Disposing from a keep-alive handler no longer deadlocks (L7-3).**
`Dispose()` from a keep-alive `PublishStatusChanged` handler can return
while that callback is still finishing.
- **Transfer of a restored subscription (L7-4, G27).**
  - It succeeds even when some saved items were never created.
- The server subscription is deleted only when this session's own
TransferSubscriptions just moved it and adoption failed definitively
(item count mismatch or a non-transient status). Transient errors and
`ReactivateSubscriptionsAsync` never delete it.
  - The public `Subscription.TransferAsync` never deletes.
- **Smaller fixes:**
  - Cloned items keep their triggering links (L7-5).
  - `CreateAsync` clears stale server ids (L7-6).
- A `Good_SubscriptionTransferred` for the client's own transfer is
ignored (L7-7).
- An item removed while its create is in flight is deleted afterwards
(L7-8).
- The publish timeout for very long keep-alives no longer overflows
(L7-9).
  - A negative `MaxMessageCount` is handled (L7-10).
  - `LastMessage` tolerates a wrong notification type (L7-11).
  - Pending acks exactly 2^31 away no longer throw (L4-1).
- **Log changes:** new log events `Subscription + 68..70`.

### Redundancy
- **Warm/Hot demotion (L4-2, G1, G3).**
- Without token reuse, the demoted leader closes its session and
reconnects as a fresh standby.
- With token reuse, it abandons the shared server session locally,
without CloseSession, so the new leader can reactivate it and keep its
subscriptions. This uses the new internal methods
`ManagedSession.AbandonServerSessionAsync` and
`Session.AbandonServerSession`.
- `RoleChanged(false)` is now raised before the standby connect and no
longer depends on it, so `CurrentSession` can briefly be `null`.
- Exceptions from `RoleChanged` handlers are logged and do not stop the
teardown.
- **Promotion (L4-3, G2).** A promoted standby that adopts the leader's
session first closes its own server session. A retried promotion keeps
the session it already adopted.
- **Client failover takeover (L4-4, partial).** Subscriptions the backup
prepared in advance (not yet created, `TransferId` set to the active
client's id) are moved through the session's own transfer and keep
publishing. `docs/HighAvailability.md` is updated.
- **`ShouldFailover` through the interface (L4-6).** Calling it through
`IServerRedundancyHandler` no longer fails over away from a server that
is still Healthy.

### Fluent / dependency injection
- **Shared DI session (L10-5).** The shared session from `AddClient` is
reconnected after a caller disposes it, and is disposed with the
container. After that the connect delegate throws
`ObjectDisposedException`.
- **New public API:
`ManagedSessionBuilder.WithServerRedundancyOptions(ServerRedundancyOptions)`
(L10-6).** This is additive. The `Session.ServerRedundancy` options are
now actually applied.
- **`AddDiscoveryAndConnect` rewrites the advertised address (L10-7).**
It replaces the host and port the server advertises with those of the
discovery URL (Part 4 §5.6.2.1, NAT/containers), and prefers endpoints
with the same scheme.

### State machines and role management
- **`GetSubStateMachineAsync` returns the instance's own sub-state
machine (L10-1).** Before, it returned the type's placeholder.
- **`WaitForStateAsync` reports failures with OPC UA status codes
(L10-2).** It throws `BadNotFound` when `CurrentState/Id` cannot be
resolved, and `BadInvalidState` when observation ends without reaching
the state. Before, both surfaced as `OperationCanceledException`.
- **`RoleManagementClient.ListRolesAsync` pages correctly (L10-3).** It
follows continuation points, releases them on any failure, and throws on
a Bad browse status instead of returning an empty list.
- **Role properties are read into the right fields (L10-4).** Properties
whose namespace cannot be resolved are skipped instead of shifting the
other values.

### File system, temporary files and alias names
- **Path escaping (L11-8, G12).**
- Path segments escape `:` and `/` with `&`, and `&` itself as `&&`
before those characters or at the end of a name.
- `Format` and `Parse` round-trip all names. Typed input ending in `&/`
now reads the slash as part of the name.
- A segment without a namespace prefix also matches a namespace-0 child
when nothing matches in the parent's namespace.
- **Stale path cache (L11-1).** When a cached lookup fails,
`GetInfoAsync` retries once from the server. `ExistsAsync` and
`GetFileAsync` report "not found" instead of throwing.
- **`GenerateFileForReadAsync` waits for the file (L11-2).** It waits
until the file-generation state machine reaches ReadTransfer (`Idle`
counts as not started yet), and throws `IOException` if it reports
Error. The wait is bounded only by the caller's token.
- **Non-recursive delete refuses hidden children (L11-3).** It refuses
when the directory holds children that the subtype options hide from
enumeration. Before, the server deleted them all.
- **Alias names (L11-5, L11-6, L11-7).**
- `BadMethodInvalid` maps to `NotSupportedException` for all alias
calls, so `UseVerbose` falls back to `FindAlias`.
  - A duplicate alias name resolves to all its targets.
- If the refresh strategy fails to start, the resolver logs a warning
and keeps working without automatic invalidation. New log event block
`AliasNameResolver = 560`.
- **Null profile entries (L11-4).** Null `ServerProfileArray` entries no
longer crash `GetConformanceInfoAsync`.

### WebApi transport
- **Failures come back as `ServiceResultException` (L12-1).**
  - A timeout becomes `BadRequestTimeout`.
- HTTP 429/503 becomes `BadServerTooBusy` with the Retry-After hint, on
every target framework. `WebApiClient` checks the status itself (reusing
`HttpsTransportChannel.CreateServerTooBusyException`), so callers of
`WebApiClient` also get a `ServiceResultException` instead of an
`HttpRequestException` for these two statuses (G15).
  - An IO error becomes `BadNotConnected`.
- **Timeouts (L12-1, G14).**
- `OperationTimeout` applies to each request. When `RequestTimeout` is
unset, HttpClient's 100 s default no longer cuts off long Publish
requests.
- The GetEndpoints call at open is bounded by `OperationTimeout`, and
cancelling the open now throws.
- **Core change:** `HttpsTransportChannel.MapRequestFailure` went from
private to internal so the WebApi channel can reuse it.

### ComplexTypes
- **Out-of-range union selector (L12-3).** A union whose SwitchField is
larger than its field count now fails with `BadDecodingError` when
decoded and `BadEncodingError` when encoded (Part 6 §5.2.8).
- **Verbose JSON unions (L12-4).** They now decode their selected field
instead of `null`.

## Not fixed / partial
- **L2-5 (skipped):** an identity provider combined with a
caller-supplied reverse connection still can't connect to an
undiscovered endpoint. Fixing it means choosing the identity after
CreateSession, a design change.
- **L4-5 (skipped):** the one-time KeyCredential token needs a fresh
token on each reactivation. Today reactivation fails and the client
falls back to a new session.
- **L4-4 (partial):** only subscriptions the backup prepared in advance
survive a takeover.
- **L3-2 (partial):** `AddNodes`/`RegisterNodes` batches are not rolled
back.
- **L2-3 (partial):** service calls still hold the session lock for
their whole round trip.
- **Known from the review, not fixed here:**
  - G7: the batch cleanup request can't be cancelled.
- G11: the DI session's close at host shutdown never reaches the server,
and a closed session keeps being handed out.
- G13: a file renamed by another client is still found under its old
path.
  - G25: a clone-based transfer doesn't mark the original subscriptions.
  - G27b: the transfer item check matches by count, not by ID.
- **Outside this PR:** the reference server ignores `ECDHPolicyUri` on
ActivateSession (`SessionSecurityPolicyHelper`), which breaks Part 6
§6.8.2. As a result, the L1-4 two-step ECC switch ends in
`BadSecurityPolicyRejected` against our own server.

## Testing
All suites on net10.0, on the branch before the master merge. Every
suite had 0 failures:

| Suite | Passed | Skipped |
|---|---|---|
| Opc.Ua.Client.Tests | 2698 | 0 |
| Opc.Ua.Redundancy.Client.Tests | 134 | 0 |
| Opc.Ua.Subscriptions.Classic.Tests | 57 | 0 |
| Opc.Ua.Bindings.Https.WebApi.Tests | 385 | 0 |
| Opc.Ua.Sessions.Tests | 782 | 379 |
| Opc.Ua.Subscriptions.Tests | 640 | 6 |
| Opc.Ua.Client.ComplexTypes.Tests | 2858 | 0 |

After merging current master (net10.0), every suite had 0 failures
except one, a flaky new test fixed in 9f52952b2:

| Suite | Passed | Skipped | Failed |
|---|---|---|---|
| Opc.Ua.Client.Tests | 2719 | 0 | 1 (the flaky test) |
| Opc.Ua.Redundancy.Client.Tests | 134 | 0 | 0 |
| Opc.Ua.Client.ComplexTypes.Tests | 2858 | 0 | 0 |
| Opc.Ua.Subscriptions.Classic.Tests | 57 | 0 | 0 |
| Opc.Ua.Bindings.Https.WebApi.Tests | 397 | 0 | 0 |
| Opc.Ua.Sessions.Tests | 790 | 379 | 0 |
| Opc.Ua.Subscriptions.Tests | 640 | 6 | 0 |

The touched test projects also build on net48 with 0 warnings.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: marcschier <11168470+marcschier@users.noreply.github.com>
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
2026-09-29 09:34:03 +00:00
Marc SchierandCopilot 46fa7d364a Harden recovery, concurrency, and resource lifetimes across the OPC UA stack (#4516)
# Description

Bound managed-session recovery, preserve Publish workers and recovery
ownership, and address the client, server, transport, and certificate
audit findings and subsequent concurrency review. Also reduce the memory
retained by exhaustive session-test diagnostics.

## Recovery and Publish ownership

- Add `ManagedSessionOptions.ChannelReconnectTimeout` through direct
construction, the fluent builder, and DI. The automatic duration is
`max(3 * KeepAliveInterval, revised SessionTimeout, OperationTimeout)`,
sampled at cycle start. Positive overrides are supported;
`Timeout.InfiniteTimeSpan` explicitly opts out. Raw sessions retain
their unlimited default.
- Add `CreateReconnectBudget(TimeProvider)` as a required
`IReconnectParticipant` member, as agreed in review. Custom participants
implement it and may return null for no participant-specific bound.
- Enforce the earliest participant/caller deadline through transport
reconnect, activation/recreation, and subscription restoration. Late
callers can shorten an active cycle but cannot extend it.
- Cancel and unwind recovery, fence late responses, and release channel
recovery ownership before the existing `Faulted` event hands control to
the outer reconnect/failover policy. Preserve session recreate admission
through final Publish cleanup and keepalive suppression until shared
recovery is complete.
- Treat participant budget creation/evaluation failures, including
exceptions at the exact deadline, as terminal shared-recovery failures.
Notify participants before exposing `Faulted`, preserve the original
diagnostic, and never silently replace a finite budget with unlimited
recovery.
- Keep caller-supplied replacement channels, managed bindings, wrapper
event subscriptions, and recovery-owner identities consistent across
success, failure, and cancellation. Reject replacement during active
recovery and fence retired callbacks so they cannot clear newer
ownership or suppress later keepalive recovery.
- Retain eligible Publish workers through temporary
subscription-identifier clearing without retaining workers for
never-created or removed subscriptions. Preserve cancellation,
acknowledgement rollback, and drain-before-replacement ordering.
- Coordinate automatic subscription updates with session recovery:
cancel admitted updates, keep them paused across a failed-restoration
handoff, and retry only after explicit restoration completes. This
prevents competing CreateSubscription requests and updates against a
retiring session, while preserving manual recreation, transfer fallback,
and pending option changes.
- Exercise the real ManagedSession, V2 subscription engine, and channel
ready gate with scripted transports and an injected clock. Cover
transfer fallback, deadline handoff, late completions, and resumed
notification delivery.

## Audit and review corrections

- Correct certificate/trust-list transactions, change-pump lifetimes,
validation, peer revalidation, and reset/resource ownership.
- Harden node admission, attribute/range/dimension validation,
monitored-item sampling and lifecycle transitions, event fanout, and
server shutdown. Run lifecycle readiness and compensation outside shared
monitored-item admission, with stale-completion ownership checks.
- Close synchronous node-manager admission before teardown and retain
resources until admitted service, lifecycle, and asynchronous method
work returns. Dispose the monitored-item manager outside both locks,
reject late calls before they can reach it, and forward asynchronous
disposal through the adapter so the master awaits the same completion.
Preserve reentrant shutdown initiation, cancellation/failure unwinding,
and shared cleanup-failure reporting.
- Bound WSS pending-request retention using connection-local wire
handles while preserving caller-visible request handles and translating
Cancel targets. Safely ignore retired replies and drain admitted
send/close users before resource disposal.
- Clarify that the shared `ClientBase` caller-handle sequence is
distinct from the non-wrapping WSS wire allocator. Existing
exhaustion/reopen, late-reply, and Cancel-translation regressions verify
the connection-local contract; no allocator behavior was changed by this
clarification.
- Preserve virtual-node validation and resolver service errors instead
of converting them to cached misses. A mismatched NodeId reports
`BadNodeIdInvalid`; callback type mismatches and resolver service errors
keep their exact status. Per-item boundaries preserve unaffected reads,
writes, history operations, method calls, browse paths, and
monitored-item creation/restoration, including permission-validation
paths. Caller cancellation still propagates; stored-item validation
failures are logged without aborting later restores.
- Correct client file/role/state-machine/streaming APIs, node-cache
behavior, redundancy/failover ownership, and session
configuration/identity handling.
- Cancel each owned peer-discovery scope before disposing it, including
when the bounded wait wins a cancellation-delivery race. Keep late
results out of the endpoint cache and preserve single-flight lookup
ownership.
- Keep materialized alias Browse results synchronized with the live
store by default, preserving explicit startup-only opt-out. Apply
HistoryUpdate service results per value while retaining explicit
all-or-nothing provider APIs.
- Update the directly related feature documentation and add focused
positive, negative, concurrency, and ownership regressions.

## Latest review-feedback corrections

- Fence stale failed lease observations with a successful-confirmation
generation distinct from the revocation epoch. Snapshot it before each
store read, including failed-CAS revalidation, so an old failure cannot
revoke or reschedule a newer lease while fresh ownership loss still
revokes leadership. Preserve independent overlapping acquisitions,
expiry, disposal, and late-success protections.
- Isolate attributable WSS response-decoding errors to their request,
including retired handles. Keep admitted socket sends connection-owned
so caller timeout/cancellation cannot abort sibling requests; shutdown
still cancels and drains those sends.
- Restart keepalive and classic Publish replenishment after successful
session reuse. Retire V2 worker demand after intentional
deletion/disable without confusing that state with temporary recovery
resets.
- Browse virtual directories lazily across continuation pages without
the 1,024-entry snapshot cap. Preserve active-page cancellation, bounded
metadata retention, pushback, and exactly-once asynchronous cursor
cleanup.
- Apply certificate/CRL staging in last-operation order, preflight
required issuer storage before writes, select actual policy-compatible
RSA keys for None endpoints, frame certificate chains independently of
signature OIDs, and preserve admitted validation results during
rejected-writer shutdown.
- Preserve base asynchronous disposal when a legacy override omits its
base call; avoid double derived disposal in the adapter. Let genuinely
admitted nested work finish while rejecting stale captured contexts and
returning null from closed lookup APIs.
- Re-park recovered monitored items if AddNodes rolls back. Give event
compensation a fresh finite deadline, and preserve healthy
Browse/Translate siblings at every reference/path boundary while
retaining starting-node errors and caller cancellation.
- Give final reconnect notifications a live, bounded shutdown-linked
lifetime. Synchronize child state before parent lifecycle handlers
outside the parent transition lock.
- Document the accepted existing policies: direct reverse connections
are single-use without a ReverseConnectManager, and multi-node stream
capacity is shared rather than reserved per node.

The expanded readiness controls also exposed a real generation-handoff
race: an old source could finish draining after activation was deferred
but before readiness tasks were collected, causing the wanted
replacement to be omitted from the wait set. A deterministic test gates
that exact interval; the fix keeps the replacement in the readiness
wait. The original race passed 200 repetitions after the fix. A separate
control now awaits both producer readiness and iterator entry under the
same original deadline, rather than treating those independent signals
as equivalent. Temporary logging and repetition are removed.

## CI integration contracts

The History and Server CI failures exposed integration tests that still
asserted the behavior intentionally changed by the audit fixes. A
Windows WoT negative test raced its caller deadline against upstream
retries. A subsequent Ubuntu Client failure exposed a real
automatic-update versus explicit-restoration race:

- History insertion collisions now verify exact per-value statuses and
all persisted timestamps/values, including preservation of the existing
conflicting entry. Explicit atomic-provider rollback controls remain.
- Alias materialization tests wait for actual publication and verify the
added node plus forward/inverse `AliasFor` references, instead of racing
a startup-only snapshot expectation. Explicit refresh opt-out controls
remain.
- The unavailable-upstream WoT test uses an explicit finite retry policy
through existing DI configuration, preserving its original four-minute
guard and requiring a mapped-value service error before caller
cancellation. Production retry defaults remain unchanged.
- The Client fix retains the exact one-create and late-response
assertions. Three deterministic real-subscription/real-manager cases
cover paused creation, disposal while paused, and cancellation of an
admitted create followed by explicit restoration and a pending option
update. Both composed restoration-deadline cases also prove automatic
updates stay blocked at the outer handoff and resume after restoration.
- The merged-head net48 correction prevents lost peer-resolver
cancellation and distinguishes the harness's delayed initial `Connected`
event from actual outer recovery completion. A deterministic timer-order
test covers both cooperative and cancellation-ignoring resolvers,
cancellation before return, rejection of late cached results, and a
fresh subsequent lookup.
- The remaining CodeQL alert was a false content flow through
`ArrayOf.Count` into an integer-only trust-list summary. Projecting the
same count through `Span.Length` keeps cardinality distinct from
serialized contents without allocating, dropping diagnostics,
suppressing the rule, or dismissing the alert. Five log-contract cases
cover null/empty/nonempty results and mixed chain-capable/fallback
listeners, asserting the exact count, message, and structured
properties.
- Classic transfer acknowledges messages selected for asynchronous
Republish only after their responses arrive. The existing locked
replay-selection decision returns the immediate-acknowledgement subset
to Session, preserving the public transfer API, advertised availability,
and immediate acknowledgement of older gapped messages not selected for
replay. A callback changing `RepublishAfterTransfer` cannot change the
already-selected acknowledgement ownership.
- Transfer integration tests explicitly control acknowledged versus
retained origin messages. Exact assertions distinguish retained replay
from requested fresh initial values by sequence number, client handles,
values, status, and source timestamp. Atomic counters, observed
delivery/keepalive progress, and failure-safe session/file cleanup
replace timing assumptions and racy resets.
- Server lifecycle tests verify the documented independent five-second
compensation deadline rather than requiring a non-cancellable token.
They cancel the actual request, prove compensation and unrelated
monitored-item creation still proceed one tick before the deadline,
preserve the original failure and ownership assertions, and verify the
completed deadline is retired.
- Synchronous and asynchronous directory-browser tests require the exact
provider exception instead of an empty-directory success, then verify
the failed cursor is not enumerated again. These correct expectations
left behind by the intentional, documented provider-error propagation
change; production behavior is unchanged.

No tests were disabled, assertions loosened, coverage thresholds
lowered, or CI checks made optional. Existing platform exclusions and
Explicit debug variants remain.

## Related Issues

- Fixes #4514
- Fixes #4515
- Builds on merged #4503 and retains the #4508 publishing-drain
behavior.

## Validation

**Lease-election review correction
(`a13afa641182c70983e16bbcfebf507e666a45a5`):**

The correction is based on the existing upstream merge
`43079e2b851fe338a4082066f8d14abfdafb6e32`. Three deterministic
stale-verdict
cases fail on the original source and pass with separate confirmation
fencing.
Six new cases cover the initial foreign-owner verdict, failed-CAS
revalidation
in both invocation orders, and fresh ownership loss through both read
paths,
including revalidation begun after another successful confirmation.

| Target and configuration | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net10.0 Debug | 120 | 0 | 0 |
| net48 Debug | 120 | 0 | 0 |

The selection is the full `Opc.Ua.Core.Tests.Redundancy` namespace,
including
all 38 `SharedStoreLeaseElectionTests` cases and the existing expiry,
clock
rollback, disposal, and overlapping-success regressions. New witnesses
are
`StaleForeignLeaseReadDoesNotRevokeNewerAcquisitionAsync`,
`StaleFailedRevalidationDoesNotRevokeNewerAcquisitionAsync`, and
`FreshForeignLeaseObservationRevokesLeadershipAsync`. They assert
resulting
leadership, exact transitions, independent progress, and the unchanged
expiry
boundary. Retaining the initial generation for the fallback read
independently
makes the fresh-loss-after-confirmation control fail; that mutation was
removed
before the final rebuilt runs.

The successful scoped command is
`dotnet test tests\Opc.Ua.Core.Tests\Opc.Ua.Core.Tests.csproj -c Debug
--no-restore --filter
"FullyQualifiedName~Opc.Ua.Core.Tests.Redundancy"`,
with `CustomTestTarget` and `-f` matching each row and that framework's
assets
restored. Both changed C# files pass formatting and analyzers through
informational severity on both frameworks. These are scoped results, not
a
full-solution test or measured coverage-delta claim. CI monitoring is
paused
for this feedback-only operation; no current-head CI success is claimed.

**Latest CI contract correction
(`1cd1f2047bb5b50c9bf300b1ff710b0b2e935a29`):**

All four failing Server shard 23 jobs in
[run
36120946740](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/36120946740)
reported the same six cases. Two local replays reproduced all six
failures.
The source changes and documentation from `cd43b831a` establish both
intentional
contracts: independent bounded event compensation and surfaced provider
errors.
Only the two test files are corrected; production code and CI policy are
unchanged.

| Target and configuration | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net48 Debug | 113 | 0 | 0 |
| net10.0 Release, CI Coverlet settings | 113 | 0 | 0 |

The selection contains `MonitoredItemManagerLifecycleTests`,
`DirectoryObjectStateTests`, `DirectoryBrowserBoundedEnumerationTests`,
and

`EventCompensationReadinessHasFiniteDeadlineWithInfiniteSourceTimeoutAsync`.
Both changed files pass formatting and analyzers through informational
severity
on both frameworks. Independent mutations restoring a non-cancellable
compensation token and swallowing provider errors fail all four
lifecycle
cases and both browser cases, respectively. Both mutations were removed
before
the final passing runs and commit.

The scoped command is `dotnet test
tests\Opc.Ua.Server.Tests\Opc.Ua.Server.Tests.csproj`
with `CustomTestTarget` and `-f` set to the selected framework,
`--no-restore`, and
`--filter
"FullyQualifiedName~MonitoredItemManagerLifecycleTests|FullyQualifiedName~DirectoryObjectStateTests|FullyQualifiedName~DirectoryBrowserBoundedEnumerationTests|FullyQualifiedName~EventCompensationReadinessHasFiniteDeadlineWithInfiniteSourceTimeoutAsync"`.
The modern run additionally uses `-c Release /p:CollectCoverage=true
--collect "XPlat Code Coverage" --settings
tests\coverlet.runsettings.xml`.
These are scoped results, not a full-solution test or measured
coverage-delta claim.
Hosted checks for that commit were pending at publication. The fail-fast
CI
watch was stopped when the requested operation switched to review
feedback;
no current-head CI success is claimed.

**Earlier master merge (`8b15ea6ef9fc2214ac8ec886f373bb3846dd6d6f`, base
`b4136d8e9bab0df680f41d9ef985f519160534b1`):**

The `TcpListenerChannel` conflict preserves both lifetime
responsibilities:
disposal clears the retained peer-certificate chain and unregisters the
quota-scoped message-assembly scheduler. Both fields and all upstream
deadline
handling remain intact. The only additional manual source adjustment
adds the
parentheses required by the existing analyzer around the session-count
fallback.

Master advanced during validation. The initial transport merge
`80303c434ce813cf75aa7fe54a6a32fe2aeafc30` was retained, and the newer
base was
merged normally in `8b15ea6ef9fc2214ac8ec886f373bb3846dd6d6f`, without
rewriting
history. The additional recovery, fluent-pipeline, and test-framework
overlaps
were inspected; the branch's cancellation, validation-error, and
acknowledgement
ownership fixes remain alongside the upstream changes.

Full `UA.slnx` builds passed on net10.0 and net48 with **0 warnings and
0 errors**.
The final scoped tests rebuilt against the committed tree
`2074f8efcb61d8d9c6106e7d6f76ee941940e358`:

| Target | Passed | Failed | Skipped |
| --- | ---: | ---: | ---: |
| net10.0 | 2,653 | 0 | 0 |
| net48 | 2,529 | 0 | 7 |

The net48 skips are existing platform exclusions: six RSA_DH_AesGcm
nonce cases
and one ClientWebSocket certificate-validation case requiring .NET 7 or
later.
The selection covers transport cleanup, reassembly
budgets/deadlines/admission,
peer-chain ownership, server session binding, fluent lifecycles and
source
generation, reconnect and keepalive, transfer acknowledgements, Publish
queues,
and JSON encoding. Modern-.NET WSS transport and real-server integration
cases
also pass. The resolved file passed solution-relative formatting and
analyzer
verification through informational severity on both frameworks.

These are scoped test results, not unfiltered full-suite or
measured-coverage
claims. Hosted CI was not monitored or repaired as part of this
merge-only
operation.

Selected local results below are overlapping validation runs, not
distinct-test totals.

**Earlier review-feedback batch
(`cd43b831a8f11de3f7d65c3681712a61e3c669a5`):**
The final net10.0 scoped selection passed **471 tests, with no failures
or skips**.
The final net48 solution-root selection passed **439 tests, with no
failures and
one unchanged platform skip**
(`ValidateServerCertificateFallsBackToTlsPolicyErrors`,
which requires newer ClientWebSocket certificate-validation support).
Both full nonincremental solution builds completed with **0 warnings and
0 errors**,
and all **40 changed C# files** passed informational-level
formatting/analyzer
verification. Both frameworks validated the identical final tracked
diff.
The focused matrix covers every one of the 20 current review threads,
including
real mid-frame WSS cancellation, stale admission contexts, directory
continuation
ownership, multi-element Browse/Translate failures, and the readiness
drain race.
The net10.0 solution-root test command has a separate pre-existing
runner conflict:
three unrelated AOT projects reject the VSTest target under
Microsoft.Testing.Platform
2.4.0 and SDK 10. Per-project net10.0 results are recorded separately;
no runner
migration, test exclusion, assertion relaxation, or CI-policy change is
included.
These are bounded selections, not unfiltered full-suite or measured
coverage claims.
At publication of `cd43b831a`, hosted CI was not green: the
`OPCFoundation.UA-.NETStandard` check reported `ACTION_REQUIRED`,
AppVeyor reported
`FAILURE`, and the two signed-build jobs were in progress. No CI jobs
were rerun,
cancelled, approved, or repaired as part of that feedback-only
operation.

**Classic transfer correction
(`f425376fca045794122e19aaf9cafebc4a717d91`):**
The preceding head's
[macOS net10.0 shard
25/30](https://github.com/OPCFoundation/UA-.NETStandard/actions/runs/35980326299/job/107570512458)
failed
`TransferSubscriptionTest(DisconnectedRepublish).TransferSubscriptionAsync(True,False)`
at the static-node count assertion: expected 10, received 20. The trace
contains a successful,
explicitly requested republish of retained sequence 1 and a fresh
initial-value batch at sequence 3,
not duplicate dispatch of one response.

Controlled lost origin acknowledgements reproduced that incorrect test
expectation on both the
preceding PR head and exact master base
`a2539cb53dd1666cef856f33812d7a8830d68909`.
The maintainer explicitly authorized correcting this existing issue in
the PR. Retained replay
and requested initial values are independent, as specified by
[OPC UA Part 4,
TransferSubscriptions](https://reference.opcfoundation.org/specs/OPC-10000-4/5.14.7).
The reason that the original hosted run retained its particular origin
message remains unproved.

The expanded full-suite run then exposed a **real production race**, not
just a count assertion:
Session queued acknowledgements for all transferred available messages
before the asynchronous
Republish responses arrived. Publish could delete those messages first,
causing
`BadMessageNotAvailable`. A gated real-Session/classic-engine regression
failed both replay-enabled
cases on the original implementation while both no-replay controls
passed. The ownership fix
passes all 24 combinations of empty/consecutive/unsorted-gapped queues,
replay preference,
sequential delivery, and a reentrant preference change.

All 40 normal real-server transfer cases pass on both frameworks.
Independent mutations
suppressing actual replay and duplicating observed sequence records each
fail the intended
assertion; both mutations were removed. The full classic suite passes on
both frameworks.
Hosted CI was pending when that correction was published; the earlier
failed hosted job was not
rerun for a lucky pass.

**Local net48 caveat:** the full Client run timed out in the
pre-existing fake-clock test
`ReconnectAsyncSwapsFaultedLeaseEntryAsync`, which does not exercise
subscription transfer.
Its unchanged isolated replay passed, but that does not resolve the
full-suite timeout.
No unrelated code or assertions were changed, and a clean full Client
net48 run is not claimed.

| Scope | net10.0 | net48 |
| --- | --- | --- |
| Full Client.Tests after transfer acknowledgement correction | 2,549
passed | 2,552 passed, 1 timeout failure noted above, 1 existing
platform skip |
| Full classic-subscription project after transfer correction | 57
passed, including all 40 normal transfer cases | 57 passed, including
all 40 normal transfer cases |
| Gated transferred-message acknowledgement ownership | 24 passed,
included above | 24 passed, included above |
| Saved-session consumer of the shared subscription helper | 40 passed |
16 passed, 24 existing unsupported-security-policy skips |
| Audit regression matrix | 2,339 passed | 1,934 passed, 34 existing
skips |
| Full Client.Tests after review follow-ups | 2,520 passed | Focused
selections only |
| Full Client.Tests after CI recovery correction | 2,523 passed, CI
coverage collector | 2,527 passed, 1 existing platform skip |
| Latest merged-head recovery/redundancy selection | 139 passed | 139
passed |
| Full Client.Tests after merged-head net48 correction | Focused
selection above | 2,529 passed, 1 existing platform skip |
| Lifecycle and actual-dimension regressions | 146 passed | 146 passed |
| Focused recovery follow-ups | 7 passed | 7 passed |
| WSS-related fixtures | 93 passed | Not applicable |
| CI History integration corrections | 28 passed | 28 passed |
| CI alias, dispatcher, and explicit-atomic controls | 63 passed | 63
passed |
| Full WoT sample project with CI coverage collector | 29 passed | Not
applicable |
| Trust-list effects and count-only summary contract | 22 passed | 22
passed |
| Virtual-node feedback, node-manager, dispatcher, and lifecycle
selections | 661 passed, 63 existing not-executed cases; all 48
virtual-node cases passed | 661 passed, 63 existing not-executed cases;
all 48 virtual-node cases passed |
| WSS wire-handle exhaustion, late replies, and Cancel translation | 9
passed | Not applicable |
| Synchronous node-manager disposal and related service/lifecycle suites
| 1,037 passed, 64 not-executed cases from existing fixture assumptions;
all 93 sampling/disposal cases passed | 1,037 passed, 64 not-executed
cases from existing fixture assumptions; all 93 sampling/disposal cases
passed |

- Full solution builds passed on net10.0 and net48 during the audit
work. The subsequent full non-incremental net10.0 build also completed
with zero warnings/errors.
- Modified source/test formatting and analyzer checks passed through
informational severity.
- Original composed recovery regressions passed repeated runs on both
frameworks. Independent mutations removing Publish cancellation,
bypassing the recreate drain call, or ignoring ready-gate cancellation
each failed the intended assertion; all mutations were restored before
passing runs.
- The latest recovery correction passed 100 executions of each original
restoration-deadline scenario with unchanged assertions. Restoring
premature update admission independently made both strengthened handoff
cases fail; the correct retention behavior was restored afterward.
- Startup-event and cancellation-delivery timing probes reproduced the
subsequent net48 failures, then passed 100 executions of each of the
three scenarios with the fixes. All timing probes and repetition were
removed. The permanent timeout-order regression also went RED on the
original cancellation cleanup without sleeps or scheduling
amplification.
- Final post-format recovery/subscription/engine checks passed all 151
selected cases on net10.0. The first local full net48 attempt aborted in
`clr.dll` with native access violation `0xc0000005`; an
unchanged-assembly full diagnostic rerun passed as recorded above. That
native host crash has not been attributed or claimed fixed.
- A minimal replay with the same CodeQL CLI and query-pack versions
reproduced the custom-count alert and confirmed that the standard
span-length projection is clean while direct sensitive-value and
raw-identifier logging controls remain flagged. The source was already
logging only a count; no identifier or certificate disclosure was
established at the reported location.
- The virtual-node feedback regressions first reproduced five
error-preservation/cache failures; expanded service-dispatch cases
exposed two additional whole-batch failures before the
operation-boundary fixes. The final selections pass on both frameworks.
Genuine misses remain cached, successful results remain reusable, failed
validation allows same-cache retry, and request cancellation still stops
the batch.
- Three deterministic synchronous-manager disposal regressions
reproduced early resource release and lifecycle calls reaching a manager
during disposal. The fix passes direct and adapted calls, a
sampling-worker join after the last operation exits, reentrant shutdown,
cancellation and failure paths, repeated disposal, and exact rejection
across 39 service/lifecycle entry points both during drain and after
cleanup. The original outside-node-lock disposal regression remains and
now requires the worker to observe closed admission.
- Prior-head CI on `c985f8bded77a60449d9cd381c8a004d8590ccf6` completed
with **168 passing checks, one expected release-package-publication
skip, and no failures or pending checks**. All test shards, signed
builds, container builds, the coverage check, and the CodeQL PR check
passed. Hosted CodeQL analysis `1829262912` completed successfully and
marks count-flow alert 385 fixed. This is evidence for that head, not a
claim that subsequent review follow-ups have completed hosted CI.

### Session-test diagnostic memory

Complete browse listings are streamed to unique NUnit attachments rather
than retained in inline NUnit/VSTest output. Detached regression-test
results are cleaned up without deleting runner-collected attachments.

- Two covered session-suite runs each completed with 782 passed and 379
existing skips. Peak working set fell from 4.86 GiB to 2.44-2.78 GiB.
- TRX output shrank from 303.1 MiB to approximately 40.7 MiB, retaining
all 46 complete browse attachments.
- Seven output regressions cover exact content, empty/single/large
listings, disabled/enabled output, bounded inline summaries, and unique
filenames.

The separate Azure build-18452 VM deprovisioning cause remains unproved
without provider logs. The memory measurements do not establish its
cause.

Unfiltered local `UA.slnx` tests, including the long stress/soak suites,
have not been run on both frameworks. A local coverage delta was not
collected; builds and focused tests are not substitutes for those
claims.

## Checklist

- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [ ] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] All checks on the latest review-follow-up head have completed
successfully; prior-head CI passed as recorded above.
- [x] I have addressed **all** PR feedback received.

Tests have been added and pass as recorded above; the hosted coverage
check passed on the prior head identified above. The combined
tests/coverage-increase checkbox remains open because no local coverage
delta was measured.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 68f26810-22b8-476f-abcd-0a8c82d6e208
2026-09-25 14:59:34 +00:00
Marc SchierandCopilot 138086863b Fix audit findings and review regressions across the OPC UA stack (#4503)
## Scope

Audit fixes and review follow-ups across the OPC UA Core, Client,
Server, transport, and redundancy components. This includes implemented
Tier 1, Tier 2, and Tier 3 work; it does not claim that every item in
the 244-finding audit backlog is complete.

The review batch fixes mandatory full-key record protection and owned
plaintext buffers; transactional pending-certificate claims;
shared-channel nonce and certificate ownership; discovery and
token-policy validation; reconnect/callback ordering without changing
unbounded buffering defaults; server permissions, filters,
monitored-item lifetime, and alarm topology; historian paging,
retention, and annotations; atomic user/password metadata; and canonical
file identities with bounded alias and role refresh workers.

## Review-batch verification at `ab686ccae`

The following results come from fresh test builds using `dotnet test`,
`--no-restore`, `-m:1`, and an explicit `CustomTestTarget`. They replace
the earlier description's library-build/`--no-build` totals, which did
not establish the state of the merged test sources.

| Scope | Target | Passed | Skipped |
|---|---|---:|---:|
| Core review regressions | net10.0 | 827 | 0 |
| Client and lifecycle regressions | net10.0 | 630 | 0 |
| Server review regressions | net10.0 | 1970 | 0 |
| Redundancy Server / Client / PubSub | net10.0 | 276 / 10 / 11 | 0 |
| Sessions / file-and-alias / streaming / HTTPS-WSS integration |
net10.0 | 8 / 21 / 30 / 20 | 0 |
| Core review regressions | net48 | 786 | 39 |
| Client recovery and policy regressions | net48 | 54 | 0 |
| Server ownership, aliases, queues, and user-state regressions | net48
| 137 | 0 |

Every listed run exited successfully. The 39 net48 skips are existing
platform/capability cases. New key-agreement tests assert
unavailable-policy behavior on unsupported targets rather than adding
skips or pretending those targets performed an unsupported handshake.
Additional exact node/permission/filter/alarm checks passed 13 Core and
46 Server cases.

The PR-scoped formatter verification covers 26 projects and 389
non-generated C# files. A Roslyn syntax audit covers 53 changed
interfaces and 263 members, with no missing
parameter/type-parameter/return contracts and a 120-column limit for
their declarations and documentation. No full-solution,
all-target-framework, or NativeAOT matrix is claimed from these local
runs; the new CI run must establish its own result.

## CI follow-up at `e1bc3ac3b`

The follow-up fixes the failures reported by Azure build 18400. TLS
certificates retain configured DNS names, including mixed-case URI
schemes, without relaxing hostname validation. Reverse-WSS fixtures use
the DNS identity in the client certificate. Reconnect completion is
published only after cycle cleanup, so a subsequent reconnect cannot
join an old completed cycle and retain old certificates.

Certificate-alarm roots now support event subscriptions. The pump sample
has one continuous notifier path, with no duplicate shortcut. Historian
and aggregate fixtures share the provider's retention clock. Alarm
collection lets the server expire idle Publish requests rather than
canceling only the client wait. The corrected server, WoT, and
managed-session fixtures exercise valid requests and initialized
lifecycle contracts. Downlevel crypto tests preserve real credential and
key-ownership assertions without enabling unsupported raw-ECDH policies
or adding skips.

Fresh local evidence after integration includes:

| Scope | Target | Passed | Skipped |
|---|---|---:|---:|
| Client lifecycle / channel ownership / builder fixtures | net10.0 and
net48, each | 96 / 103 / 123 | 0 |
| Combined server lifecycle, events, aggregates, crypto, and contracts |
net48 | 358 | 0 |
| Full lifecycle plus certificate-alarm and aggregate fixtures | net10.0
| 116 | 0 |
| Final server-contract and history-routing delta | net10.0 and net48,
each | 84 | 0 |
| Subscription / XRegistry / WoT event regressions | net10.0 | 7 / 2 / 3
| 0 |
| Full Sessions project | net10.0 | 780 | 379 |
| Full ComplexTypes project / downlevel resolver fixtures | net10.0 /
net48 | 2854 / 15 | 0 |
| Full WoT project / downlevel structured-write fixtures | net10.0 /
net48 | 1496 / 27 | 0 |
| TLS domain-name regressions | net10.0 and net48, each | 21 | 0 |

All listed runs exited 0. The Sessions skips come from existing endpoint
and policy capability guards; they are not counted as passes. No skip
was added. Worker validation also covered full DI (426 passes), full
History (540 passes, 21 existing skips), 38 exact downlevel
event/history failures, and 60 repeated certificate-rotation race cases.
The final crypto fixtures passed 73 cases on each target with the
unchanged leak detector; a temporary premature-disposal mutation made
all three borrower tests fail and was then removed.

All 29 C# files in this follow-up pass included-file formatting at info
severity across 12 projects. The complete PR interface audit now covers
54 interfaces and 271 members with zero missing contracts or line-width
findings. No full-solution or NativeAOT matrix is claimed. New-head CI
has started and remains authoritative for the remote result.

## Test-result gate follow-up at `4b6e1203a`

Azure build 18401 reported the net48 Client job as successful despite a
test-host crash after only 264 passing tests. Its old evaluator counted
per-test failures but ignored the failed run verdict. This was a partial
run, not a benign exit after the suite had completed.

The shared result evaluator now rejects aborted, errored, incomplete,
malformed, or inconsistent TRX reports. Each file must describe a
completed run, so a passing file cannot mask another file's failure. It
retains support for completed runs followed by a benign nonzero host
exit, existing skipped-result conventions, and no-TRX MTP jobs.

All 78 regression cases pass after integration using Windows PowerShell
5.1. Real completed Sessions and Client reports also pass. The
process-test fixture follows the existing NET10_0-only tools-test
pattern; its net48 build is not counted as a test run. Formatting passes
for the added test file.

The Client host crash itself has not reproduced locally. The isolated
fixture passed 59 tests, and two fresh full fast-CI selections each
completed with 2,392 passes and three existing skips, including a run
with crash collection enabled. The CI merge tree is identical to the
tested source tree. No speculative runtime change was made, and the
original partial CI run is not claimed as a full-suite pass. Azure build
18402 has now completed the full net48 Client run: 2,392 passed, three
existing console skips, and a successful test-host exit. The corrected
evaluator independently validated outcome=Completed. Across the matrix,
119 test-project jobs succeeded; Sessions net10.0 was canceled when the
remote provider deprovisioned its runner, so the overall Azure pipeline
was canceled. That cancellation is not claimed as a code failure or a
successful run. CodeQL and three Docker image jobs were still running at
the latest check. The migration discovery failure remains separate.

## Documentation follow-up at `57ed02bea`

The environment blocker has been removed by the maintainer. The three
bundled migration references now exactly match the canonical documents
after deterministic link rewriting; all 15 bundled documents pass
`validate-migration-plugin.ps1`. The canonical migration prose was not
rewritten. `FileSystemClient.md` now documents that extended Windows
roots preserve literal trailing-dot names, completing the filesystem
review follow-up.

The filesystem thread has been replied to and resolved after
publication. The review pass now has 108 of 110 threads resolved. The
two explanation-only threads remain open as requested; no unfinished
change request is being represented as resolved.

## Cross-platform follow-up at `0d9d936a8`

With migration discovery restored, the Linux and macOS test matrix
exposed two stale durable-subscription expectations. The expected value
83,442 encoded the old 32-bit overflow when converting 3,600 hours to
milliseconds. The existing overflow-safe server correctly returns
14,400,000 lifetime intervals at a 900 ms publishing interval. Only
those two expected constants changed; production behavior,
negotiated-hour checks, and all other assertions remain unchanged.

The exact local lifetime selection reproduced both failures before the
correction. The full durable suite now passes 36 cases with 11 existing
skips on each of net10.0 and net48. All four lifetime cases executed and
passed on both targets, and included-file info-severity formatting
passes.

## Session shutdown follow-up at `8daf7f091`

A late net48 Sessions failure exposed a shutdown race. Canceling an
in-flight keepalive read can produce a transport
`ServiceResultException`. The retiring worker treated its own
cancellation as proof that the peer was unavailable, so `CloseAsync` or
`DisposeAsync` could skip the server-side `CloseSession` request. The
worker now ignores that service error only when its own token is
canceled; genuine peer errors still update liveness.

The full integration fixture reproduced the original error-code
mismatch. Four deterministic mock-transport cases then produced three
failures and one passing genuine-error control before the fix. They
verify successful close, returned server error, asynchronous disposal,
and unchanged behavior for a real keepalive failure. Fresh related runs
pass 75 client and 101 integration cases on each of net48 and net10.0,
with no skips. Ten repetitions of the formerly flaky full net48 fixture
pass all 1,010 cases. All three changed files pass info-severity
formatting, and temporary diagnostic instrumentation was removed.

## Atomic listener snapshot follow-up at `82dc22b5d`

Ubuntu Core CI exposed an unsafe formatter rewrite in TCP listener
disposal: `ConcurrentDictionary.ToArray()` had become a collection
spread. A concurrent channel removal between the spread's count and copy
operations could leave a default entry, causing a null dereference
during disposal. The listener now uses the dictionary's atomic `Values`
snapshot and disposes those channels outside the listener lock.

Deterministic regressions close zero, one, or all channels at the copy
boundary. Before the fix, the one/all-removal cases reproduced the exact
null dereference; the unchanged-count control passed. All 23
admission/listener cases now pass on net10.0 and net48, and the full
fast Core net10.0 suite passes 5,267 cases with 88 existing platform
skips. Both changed files pass info-severity formatting. A bounded audit
of the formatter's other snapshot rewrites found no further verified
unsafe concurrent-registry copies.

## Shutdown-test observation follow-up at `58403ee8b`

The net48 shutdown-order test raced its own observation: it read
`m_publishWorkerTask` after starting shutdown, which can legitimately
drain the worker and clear that field immediately. The test now captures
the worker before shutdown starts and confirms it is initially running.
It still requires the worker to finish while shutdown remains blocked by
the held manager semaphore. Production behavior is unchanged.

A temporary scheduling perturbation reproduced the exact null-field
failure. The corrected capture passed 100 perturbed iterations; both the
temporary repeat and yield were then removed. The final 126
subscription/lifecycle cases pass on each of net48 and net10.0, and
formatting passes. A complete local Sessions net10.0 run also passed 780
cases with 379 existing capability skips in 7m20s after the earlier
keepalive correction.

## Retirement and alias-startup follow-up at `1a048ff39`

The shadow-generation test now observes its documented asynchronous
cleanup through the existing bounded helper. Removing the replacement
does not join a background drain that already claimed the retired
generation. The test still checks live-registration removal immediately
and requires the old node to disappear; no timeout or production
lifecycle behavior changed. All 81 lifecycle cases pass on each of
net10.0 and net48.

Initial alias-node materialization now retries one timed-out, read-only
snapshot query before creating nodes for that root. The retry is logged
through source-generated logging. Each query retains the original shared
100 ms deadline; repeated timeouts, other errors, and cancellation still
abort startup. Client searches and live refresh do not gain this
immediate retry. Fault-injection tests cover success after one timeout,
a persistent timeout, a different store failure, and cancellation. All
187 related alias/hosting cases and the original certificate-rotation
integration case pass on each target; the positive test records exactly
one retry warning. The alias documentation now accurately describes the
shared request budget.

All changed C# files pass formatter checks, and the complete
54-interface/271-member documentation audit passes. Fresh CI is running
on `1a048ff39`; the previous completed matrix exposed only the two
failures corrected in this batch and their dependent summaries.

## Sample endpoint allocation follow-up at `d08a94925`

The strong-cluster test harness allocated OPC UA and Raft endpoints in
separate released-port batches. Uniqueness was enforced only inside each
batch, so the same OS-assigned port could appear in both protocol
groups. The harness now requests one distinct batch for both groups and
splits it before launching any replicas.

Deterministic one- and three-replica allocation cases reproduced
overlapping groups with the old plan and pass with the corrected plan.
The complete 17-case short-haul sample suite passes without skips; all
failover, historian-continuation, and service assertions remain
unchanged. Both changed files pass info-severity formatting. This
prevents intra-cluster self-collisions but does not claim to reserve
released ports against unrelated external processes.

## Code-review follow-up at `085fd9636`

A review of the complete branch diff found five defects this PR
introduced. All are now fixed, each in its own commit.

`RelatedTo`'s recursive-to-iterative rewrite defaulted the optional
`includeTypeDefinitionSubtypes` and `includeReferenceTypeSubtypes`
operands to `false`. Part 4 §7.7.4 specifies both default to `true`, so
a filter that omitted them silently stopped matching subtypes.
Dynamically created key-credential nodes derived their namespace from
the containing folder, which is the standard `i=18155` node in namespace
0 — the namespace reserved for the OPC UA standard address space; they
now resolve the server-owned namespace and fail with `BadInternalError`
rather than guessing index 1. The retained audience-less
`CreateTokenData` overload produced tokens that verification always
rejects, so it is now `[Obsolete]` and throws instead. A failed
reference to a remote parent left the new node registered with a
one-sided inverse reference, and is now rolled back. An existing `.pfx`
is restricted before it is rewritten, rather than after its new key
bytes are on disk.

One further reported finding was rejected after investigation.
`JwksIssuerKeyResolver` deliberately does not dispose retired key
snapshots: `RetiredKeysAreCollectibleWhileResolverRemainsAliveAsync`
proves the resolver retains no retired snapshot, and
`ReturnedKeysSurviveRepeatedRefreshAndResolverDisposalAsync` requires
already-returned keys to keep verifying across refreshes and resolver
disposal. Adding disposal would have broken that tested contract, so the
exploratory change was reverted.

Validated on net10.0 and net48: 256 Core and 633 Server cases pass, with
one pre-existing net48 skip. The build reports zero compiler and
analyzer diagnostics, all eight included-file info-format checks pass,
the contract audit covers 58 interfaces and 310 members with no
findings, and the 15 bundled migration documents validate. All 122
review threads are resolved; the key-credential namespace thread was
reopened to retract an earlier incorrect answer and then resolved
against the real fix.
## Review-body follow-up at `da0d59cfb`

The re-review at `8daf7f091 + 82dc22b5d` listed four items in its
summary that had no inline thread of their own, so they had not been
picked up. All four are now fixed.

Both event-dispatch permission gates had been tightened from not-Bad to
`IsGood`, which silently dropped events whose permission verdict is
Uncertain; the data-change path in the same file still treated Uncertain
as deliverable, so the two had diverged. `EventSourceRegistry` only
cleared `ConsecutiveFailures` when a source was deactivated, so a source
that had backed off to the 30-second cap kept that delay for the rest of
the process even after starting successfully.
`UserNameIdentityTokenHandler` built a temporary issuer chain whose
`Add` calls take independent certificate references, and never released
them.

The fourth was the receiver-side sequence rollover, which the reviewer
had correctly re-flagged as still open despite its thread being
resolved. `m_sequenceRollover` was set permanently, so the second legal
wrap on a long-lived channel was rejected and faulted the channel along
with the transport-reconnect OPN. OPC 10000-6 does not cap a
SecureChannel at one wrap. The flag is now cleared once an accepted
number has traversed the normal range, which keeps rejecting a replayed
low number that never left the rollover window.

Validated on net10.0 and net48: 636 / 593 Core cases and 135 / 134
Server cases pass, including the new
`UaSCBinaryChannelSequenceRolloverTests` and the Uncertain-permission
delivery cases. The build reports zero compiler and analyzer diagnostics
and the changed files pass included-file info-format checks on both
targets.

The previous head `085fd9636` was fully green: 279 checks passed and
Azure build 18414 succeeded with 137 of 137 jobs, after the platform
automatically retried a job whose NuGet tool download had hit a
transient TLS error.
## Reported issues #4508 and #4509 at `6ad1ecf16`

**#4508 (V2 subscription recreate deadlocks against a faulted transport)
was not yet fixed and is now closed by `bac260a06`.** Both drain sites
the report identifies were still unbounded. A publish worker that
started its request before the quiesce parks inside the service call on
the channel ready gate while holding an active publish request; the
recreate that would make the channel ready is the very operation
awaiting the drain, so the wait never ends.

The drain now cancels in-flight attempts through a per-attempt token
linked to the worker token. An aborted worker rolls its acknowledgements
back, releases the request and returns to the paused park instead of
terminating, so it resumes when the caller leaves the quiesce. Publish
ingress stays quiesced for the caller's operation, so
`DropPendingForSubscription` keeps the guarantee the report asks to
preserve and no blind timeout is added. The new regression parks a
worker on a cancellable gate that never completes on its own: it
reproduces the hang for the full 30-second budget before the change and
passes after it.

**#4509 (identity provider fails the initial connect) was already fixed
for its primary symptom.** `HandleConnectAsync` materializes the
provider's identity through `CreateIdentitySelectionContext` before the
first `CreateAsync`, so Anonymous is no longer substituted against a
UserName-only endpoint. `6ad1ecf16` adds the two remaining details from
the report: the enabled-policy set now includes the negotiated channel
policy, so a client cannot reject the policy it already accepted as
`NotEnabledByClient`; and when discovery has not populated the
endpoint's token policies the connect keeps the configured identity so
the attempt fails at the transport layer for the reconnect policy to
retry, instead of failing at the identity layer.

Validated on net10.0 and net48: 477 / 473 client session and
subscription cases pass, the build is free of compiler and analyzer
diagnostics, and the changed files pass included-file info-format checks
on both targets. The full `Opc.Ua.Sessions.Tests` suite also passes
locally on net10.0 with 782 passed and 379 pre-existing capability
skips.

GitHub checks are green on this head: Build and Test .NET 10.0, Docker
Sample Images CI, and NuGet Publish all succeeded. Azure build 18417
completed 134 of its 135 jobs successfully; its net10.0 Sessions job was
cancelled by the hosted-agent provider ("Received request to
deprovision"), the same infrastructure flake that hit build 18409
earlier on a head predating these changes. That job is not claimed as
passing, and the local full-suite run above covers the same project. The
previous head `da0d59cfb` completed Azure build 18415 with every job
succeeded.
## Review follow-up at `a08f0c12b`

Eleven new review threads arrived, nearly all documentation. Before
acting on each "this is new in 2.0" remark I checked the API against
`master378` rather than assuming, because a genuine 1.5 API still needs
its migration entry.

`ManagedSession`'s server-redundancy refresh had two hard-coded
two-second bounds. The new `ServerRedundancyOptions` exposes
`RefreshTimeout` for the metadata read and `PeerDiscoveryTimeout` for
each peer lookup, defaults both to the previous two seconds, validates
that a bound is positive or `Timeout.InfiniteTimeSpan`, and flows
through `ManagedSessionOptions`, `ManagedSession.CreateAsync`, the
fluent builder, and `DefaultServerRedundancyHandler`.

`AsyncCustomNodeManager` and `KeyCredentialBridgeAuthenticator` are both
absent from `master378`, so their obsolete members had no compatibility
constraint and are removed rather than carried:
`AsyncCustomNodeManager.ReadInitialValue`, the audience-less
`CreateTokenData` that only threw, and the audience-less `CreateProof`
that produced a proof no server accepts.
`CustomNodeManager2.ReadInitialValue` and the `MonitoredNode2` migration
section are genuine 1.5 APIs and are untouched.

The documentation now states master's behaviour instead of the delta
from 1.5.378, with each moved item already covered under
`docs/migrate/2.0.x/`. `IHistorianAnnotationProvider` is described by
its annotation-time key rather than as "legacy" — it is new in 2.0, so
the label implied a compatibility constraint that does not exist. The
KeyCredential bridge payload's `"version"` field is explained as a
vendor-extension format version with no OPC UA counterpart, and its
version-1 upgrade narrative is gone. `CertificateManager.md`'s migration
walkthrough is replaced by the resolver API it targets.
`NodeManagers.md`, `Sessions.md`, `AsyncServerSupport.md`,
`Certificates.md`, and `Profiles.md` no longer announce features
relative to 1.5. `Benchmarks.md`, `WhatsNewIn2.0.md`,
`DeveloperGuide.md`, and `docs/migrate/` keep their 1.5.378 references,
which are their subject.

CI then exposed a defect this batch introduced: five fixtures resolve
`ManagedSession`'s private constructor by its exact positional parameter
types, so the added parameter compiled cleanly but made `GetConstructor`
return `null` at run time. `7df1d5c40` updates every site;
`Redundancy.Client` passes 126 of 126 and the affected client fixtures
112 of 112.

The BouncyCastle question is answered and tracked in #4510:
`Opc.Ua.Core` already project-references `Opc.Ua.Security.Certificates`,
which already carries the conditional BouncyCastle reference, so the
raw-ECDH polyfill belongs there rather than as a new Core dependency.
The `IUserDatabase` metadata question is addressed to another maintainer
and is deliberately left open.

## Reported issue #4509 follow-up at `5d4d13d63`

The reporter verified `6ad1ecf16` and found one case still failing,
correctly. The empty-token-policies branch kept the configured identity
so a server that is down surfaces a transport failure rather than an
identity error. A provider-only configuration has no configured
identity, so it kept `null`: `OpenCoreAsync` turned that into Anonymous
and `OpenValidateIdentity` rejected it with `BadIdentityTokenInvalid`,
silently ignoring the configured provider.

The branch now requires a configured identity to defer to. Without one
the provider is consulted, so its own `BadIdentityTokenRejected` names
the offered and rejected policy set instead. Two regression tests cover
both configurations; the first fails against the previous behaviour by
reaching the session factory with a `null` identity, which is the exact
step that produced the reported error. That branch had shipped without a
test, which is why the case was missed.

## Review and CI status at `5d4d13d63`

**All actionable review threads are resolved: 132 of 133.** The single
open thread is a question the reviewer addressed to another maintainer
about moving user metadata into `IUserDatabase`; it is left open for
them rather than resolved silently. Every resolved thread carries a
reply naming its fix commit.

**Latest-head CI is green on `5d4d13d63`: 279 checks passed, zero
failed, zero pending**, with one conditional signed-package publishing
job skipped. Local validation for this batch: the full
`Opc.Ua.Client.Tests` suite passes 2,430 of 2,430 on net10.0,
`Opc.Ua.Redundancy.Client.Tests` 126 of 126, and `Opc.Ua.Server.Tests`
590 of 590 for the affected selections. Both net10.0 and net48 build
clean for `Opc.Ua.Client`, `Opc.Ua.Server`, and the changed test
projects, and all changed files pass included-file info-severity
formatting on both targets.

The PR remains open; no merge was performed. As stated at the top, this
does not claim that every item in the 244-finding audit backlog is
complete.
## Latest CI follow-up at `b6f2dfa43`

Azure build 18442 exposed a net48 compile regression in the Kafka
adapter: `RuntimeHelpers.GetUninitializedObject` is unavailable on .NET
Framework. Commit `2cf1e0eed` now uses normal `ProducerMessage`
construction on `NETFRAMEWORK` while retaining reflection-based
construction for modern targets that can load a different Dekaf runtime
asset. The exact net48 CI selection passes 92 of 92 tests, and the
netstandard2.1 adapter guard selection passes 11 of 11.

After merging the latest `master`, GitHub Actions run 35643592139 is
green. The initial Ubuntu Core.Schema job built successfully and passed
160 of 160 tests, then hit an external 403 while finalizing its
test-result artifact; its failed-job rerun completed successfully. Azure
build 18451 was canceled when its remote provider deprovisioned the
net10.0 Sessions runner (`Received request to deprovision: The request
was cancelled by the remote provider`). Azure attached no test task log
or source error, and the canceled parent left that child check stale as
in-progress. No source workaround, test skip, or check relaxation was
made for either infrastructure failure.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 68f26810-22b8-476f-abcd-0a8c82d6e208
2026-09-22 09:10:58 +02:00
romanettandClaude Opus 5 ea93c86da2 Fix the Opc.Ua.Client defects reported by the client stack audit (#4471)
# Description

Fixes the 78 `Opc.Ua.Client` findings of a read-only bug audit of
`Opc.Ua.Client` / `Opc.Ua.Types` / `Opc.Ua.SourceGeneration` taken at
a05a36055, plus the regressions a subsequent review of those fixes
turned up. Every behavioural change was checked against the OPC UA
specification, and the citations are in the code comments.

## Session, reconnect and failover

- The reconnect `finally` re-acquired `m_reconnectLock` with the
caller's token, so a cancelled reconnect left the session stuck in
`Reconnecting` forever and every later reconnect failed. It now uses
`CancellationToken.None`.
- An in-place session recreate tore down subscriptions it should not
have: `transferred` is all-or-nothing, so a single failed transfer reset
and recreated the ones the server had just taken over, orphaning them on
the new session. `TransferSubscriptions` now reports the
per-subscription outcome and only the subscriptions the server did not
take over are recreated. A token-reuse failover keeps the same server
session, so nothing is transferred or reset there at all.
- In-place recreate only tears down the channel it created itself; a
caller-supplied channel or a channel-manager lease is left to its owner.
- `Snapshot(out SessionState)` went through the `SessionOptions` record
copy constructor, which drops every member declared on `SessionState`,
so the paired `Snapshot`/`Restore` API could not round-trip.
- The user-token policy override restored the policy URI on failure but
had already disposed the ECC ephemeral key the previous identity needs,
so the identity the rollback claims to preserve could no longer be
reactivated. The key is now parked and restored.
- `SetTriggering` batching sliced the remove list past its end when a
call had more adds than removes (Part 5 §6.3.11 bounds the *sum* of both
arrays, so an individual list may be shorter than the limit).
- The certificate-less `None` attempt dropped the request header, and
with it the ECDH ephemeral key that travels in `additionalHeader` (Part
4 §7.1/§7.15).
- `Session.Equals` compared a `ConfiguredEndpoint` against an
`EndpointDescription`, so a session did not equal a session on the same
endpoint.

## Managed session, pool and connection state machine

- `ManagedSession.Dispose()` blocked on the connection state machine's
worker, which raises `ConnectionStateChanged` synchronously — disposing
from that handler deadlocked permanently. The machine now recognises its
own flow and completes the teardown as the worker's continuation.
- `ManagedSessionFactory` dropped `updateBeforeConnect`, `connection`
and `reverseConnectManager` on all four `CreateAsync` overloads.
- The session pool ran its shared connect on no token at all, so once
the only caller gave up nothing could abort it and
`RemoveAsync`/`DisposeAsync` waited out the whole reconnect budget. Each
entry now owns the token that aborts its connect, and removal closes
*and* disposes the session.
- An explicit `engineFactory` was silently ignored for
`DefaultSessionFactory` subclasses, which quietly downgraded the session
to the classic subscription engine.

## Subscriptions

- Fixed a lock-order inversion between `m_subscriptionLock` and the
partition locks in `CompleteAsync` and `DisposeAsync`.
- `OwnsSubscriptionId` stopped at the first registered subscription
carrying the id — but in the very case it guards, the asker still holds
its own retired id, so the answer depended on `HashSet` enumeration
order and the delete could still tear down a sibling that had been
handed the recycled id.
- `MessageProcessor`'s republish gap walk was unbounded; it is now
bounded by the server's retransmission queue (Part 4 §5.14.5).
- A publish acknowledgement is sent even when a notification handler
throws — the ack means "the server may delete the message" (Part 4
§5.14.5.2), not "I processed it".
- Loaded monitored items did not raise the process-wide client-handle
counter, so a fresh process minted handles that collided with the loaded
ones; a transfer-restored item was also stamped `BadOperationAbandoned`
and left at the default monitoring mode.
- `AutoSetQueueSize` was not idempotent, so the queue size ratcheted up
on every subscription state change.
- The snapshot dropped the partition and recovery options entirely, and
clamped the sampling interval and the secondary-partition idle timeout
to zero — turning the Part 4 §7.21 "use the publishing interval"
sentinel and "never delete an idle partition" into something else.
- The state stream is positional OPC UA binary and the reader cannot
detect an absent field, so appending the partition options would have
mis-decoded every previously saved file. The stream now carries a format
version and the first format is decoded through a frozen copy of its
shape.

## Browse, node cache and the remaining clients

- Managed browse wrote a retry pass's status into whatever node happened
to sit at that offset in the caller's list, and retried
continuation-point errors without any bound. It now keeps the caller's
slot and gives up on passes that make no progress — a fixed pass cap
would cut short a large browse against a conforming server with a small
continuation-point quota.
- Continuation points are released when a consumer stops enumerating
early, as Part 4 §5.9.3.2 requires.
- The node cache reordered its batched results relative to the inputs,
which mispairs them for every consumer that matches positionally; its
supertype walks could also spin forever on a server whose `HasSubtype`
chain loops back on itself.
- A browse error was cached as "this node has no references"; it is now
surfaced to the direct caller, while the bulk and hierarchy walks treat
the node as having no references for that one operation without caching
it, so a single un-browsable node cannot fail a whole batch.
- `WebApiClient` mutated a caller-supplied (typically
`IHttpClientFactory`-pooled) `HttpClient`, which throws once that client
has sent its first request; those instances are configured per request
instead.
- `PathCache` was not thread-safe.

## Review follow-ups

The last two commits are the result of reviewing the audit fixes
themselves. Worth calling out: the `Task.WaitAsync(CancellationToken)`
polyfill in `Opc.Ua.Types` never checked `IsCompleted`, so an
already-finished task plus an already-cancelled token reported
cancellation on every pre-net8.0 target where the BCL overload returns
the result. It is now aligned with the BCL and pinned by a test.

## Related Issues

- No tracking issue; this PR is the result of a read-only audit of the
client stack.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

### Verification

35 regression tests were added under
`tests/Opc.Ua.Client.Tests/AuditRegressions/` (category
`AuditRegression`), one per fixed defect where the defect is observable
at unit level; most were mutation-checked by reintroducing the bug and
confirming the test fails.

Locally on **net10.0**: `Opc.Ua.Client.Tests` 2252/2252,
`Opc.Ua.Client.ComplexTypes.Tests` 2773/2773,
`Opc.Ua.Bindings.Https.WebApi.Tests` 346/346, and all 23 library and
test projects that reference `Opc.Ua.Client` build clean.
`Opc.Ua.Client` also builds clean for **netstandard2.1**, the target
that actually compiles the `WaitAsync` polyfill. The full **UA.slnx**
solution and the .NET Framework targets have not been run locally — left
to CI.

One pre-existing failure in `Opc.Ua.Types.Tests` is unrelated to this
branch:
`WotSpecFixtureManifestTests.EveryEmbeddedExampleMatchesItsRecordedHash`
(embedded WoT fixture hashes) fails identically with these changes
reverted.

### Notes for reviewers

- Two review findings were deliberately left unfixed and are documented
in the code: `ManagedSession.CreateAsync` has to write the engine choice
onto a caller-supplied `DefaultSessionFactory` subclass (the only
alternative is changing the `ISessionFactory.Create` contract), and the
connection state machine's "am I on my own worker" flag is an
`AsyncLocal`, so it also flows into work a `StateChanged` handler
spawns. The previous behaviour in that second case was a hard deadlock.
- `Session.Dispose()`'s single `GetAwaiter().GetResult()` bridge to
`CloseAsync` is left as is: `Dispose(bool)` must be synchronous and
`DisposeAsync` already exists.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-09-14 08:22:28 +02:00
a451053758 Fix the recurring and permanent CI failures on master (#4446)
# Description

Almost every `master` build was reporting yellow or red, which meant the
pipeline signal had stopped being useful: a genuinely broken build
looked the same as a healthy one. I triaged every `master` build from
the last week across Azure DevOps (definition 14, 38 builds) and GitHub
Actions, clustered the errors by root cause, and fixed the nine that
were still live.

The headline finding is that the two loudest problems were not test bugs
at all. Codecov rejects the upload on **28 out of 28 builds**, and that
single warning is what turned every master build `partiallySucceeded`.
Separately, the weekly HA long-haul soak was mathematically incapable of
passing: the configured duration is per *scenario*, and the two
`[NonParallelizable]` soaks run back to back, so the floor is 2 x 60
minutes plus teardown against a 110-minute step budget.

A tenth cluster (the `Opc.Ua.Sessions.Tests` reverse-connect flake, 6
hits around Aug 31) was already fixed by #4366 and has not recurred, so
it needed no work.

## Clusters and root causes

| Cluster | Frequency | Root cause |
|---|---|---|
| codecov upload exits 1 | **28/28 builds** | Codecov returns
`Repository not found`; the resulting warning made every master build
yellow |
| `No space left on device` in coverage merge | nightly | Hosted Ubuntu
agent disk exhausted by the per-matrix coverage artifacts |
| Sample HA Long-Haul timeout | weekly | 2 soaks x 60 min against a 110
min budget, so it could never pass |
| `Artifact coverage-report already exists` | on stage re-run | Pipeline
artifact names must be unique per build |
| `NodeCache*` -> `address already in use` | macOS | `ServerFixture`
retried only `BadNoCommunication`; Kestrel https throws
`IOException`/`AddressInUseException` and escaped the retry, failing the
whole `OneTimeSetUp` |
| `MetricsAreEmittedForChannelLifetimeAsync` | macOS | Entry teardown
emits `close` *before* the `active(-1)` up/down counter, but the test
only waited for `close` |
| `OnPublishReceivedKeepAliveShouldDispatchKeepAliveAsync` | net472 |
The processor queues the ack *after* dispatching the notification the
test waits on |
| `ACarriedPartIsAuthoredAtTheGripperItRidesInAsync` | macOS | A single
starved sample (0.2125 m) tripped a 0.20 m absolute worst-case bound |
| `RobotIntentLiveChannelTests` fixture timeout | net472 | 30 s startup
budget too tight, and the failure text interpolated `lastException`
*before* the polling that assigns it, so it always read `Last error: .`
|

## Approach

**Pipeline.** Coverage reporting is best-effort by design, so the
codecov step now swallows the uploader's exit code and reports the
failure as plain log output rather than a warning that colours the run.
The coverage merge job reclaims the unused Android/GHC/Swift/CodeQL
toolchains before anything writes to the agent, and qualifies its
artifact name on a retry only, so the normal first attempt still
publishes `coverage-report`. The long-haul budgets were raised above the
real floor in both the workflow and the ADO pipeline, and the display
names now say `min/scenario` so the next reader does not repeat the same
miscalculation.

**Tests.** Each test fix targets the specific ordering or bound that was
wrong, rather than adding sleeps. The two metric/ack races now wait on
the measurement the assertions actually depend on. The OpenUSD test
gates the 95th percentile instead of the absolute worst case: the defect
it guards is systematic and moves *every* sample 0.25-0.49 m while the
robot drives, so it still fails that gate loudly, while one straddled
sample no longer can.

## Worth a careful look

- **The port-collision fix is the one real behavioural change.**
`ServerFixtureUtils.IsPortUnavailable` now classifies every transport's
form of the collision, including matching Kestrel's
`AddressInUseException` by type name so the test framework needs no
reference to the ASP.NET Core connection abstractions. It deliberately
does *not* match unrelated failures, which is covered by a negative
test, so a certificate error still surfaces immediately instead of being
retried 25 times on different ports.
- **I dropped an integration test I had written for that fix.** While
validating it I found the UA-TCP listener tolerates a partial bind on
Windows, so `StartAsync` succeeds on the same port and the test asserted
something untrue. I replaced it with deterministic unit tests of the
classifier instead of shipping a test that would itself become flaky.
- **The codecov fix is a mitigation, not a cure.** The `Repository not
found` response is account-side: the `CODECOV_TOKEN` is stale or the
repository is not activated. This change stops it from colouring the
build and logs the failure plainly, but uploads will not actually land
until someone refreshes the token. Flagging that explicitly so it is not
mistaken for a full fix.

## Related Issues

N/A - this addresses CI failures observed directly on `master` builds
rather than a filed issue.

## Checklist

_Put an `x` in the boxes that apply. You can complete these step by step
after opening the PR._

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [x] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

### Notes on the checklist

- Documentation: no doc updates were needed. The changes are CI
configuration and test-harness fixes with no public API surface, and the
rationale is captured in comments at each changed site.
- Local verification: all touched projects build clean on **net10.0**
and **net48**, and the targeted tests pass (Server 5/5, Client 46/46,
Features 31/31, Robotics.Intent 20/20, plus the Di and Core.Tests
cases). One pre-existing local `net48` PKI-store failure in
`Opc.Ua.Robotics.Intent.Tests` reproduces on unmodified `master` and is
unrelated to this change; CI's `net472` leg runs that project fine.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: marcschier <11168470+marcschier@users.noreply.github.com>
2026-09-09 09:16:35 +00:00
Marc SchierandCopilot cef83550cb OPC UA Vision: a vision-guided bin-picking demo an LLM agent can see and drive (#4235)
# Description

Implements **OPC UA — Vision** and uses it to build the demo the
companion specifications were drafted for: an eye-in-hand camera watches
a bin of parts, a language model *looks at the frame*, decides which
part matches the instruction, and commands the robot through Robot
Intent — with the OpenUSD viewer showing the arm move and the bin empty
out.

> **Draft, and stacked.**
[#4195](https://github.com/OPCFoundation/UA-.NETStandard/pull/4195) has
merged and master is merged in, so what is left on top of `master` is
the Vision work plus the unmerged `marcschier/ai-model-management`
branch, which the demo needs for the model/dataset/deployment
provenance. Review the Vision commits; the AI Model Management work
lands with its own PR.

## What is here

**The specification, implemented.** `Opc.Ua.Vision` is generated from
the spec's own `Opc.Ua.Vision.NodeSet2.xml`, vendored byte-identically
(SHA-256 `79C592C6…`, verified against a fresh download and stored
LF-preserved like the Robot Intent NodeSet). `Opc.Ua.Vision.Server`
builds the §4.2 discovery object, sensors, the coordinate-frame tree,
calibrations, media endpoints, inference pipelines and the §9 feedback
methods, with rendering and inference behind injectable providers.
`Opc.Ua.Vision.Client` is built on the generated ObjectType proxies and
composes transforms across the frame tree, which is what turns a
detection in camera coordinates into a pose a robot can act on.

**Two perception paths behind one contract**, which is exactly what
`InferenceLocationEnum` is for. `OnServer` is a deterministic detector
derived from the stage's ground truth — no model, no network, no GPU, so
CI can exercise the whole loop. `EdgeOffServer` is the agent: it sees
the frame over MCP and calls `SubmitDetections`, and the Server
publishes results it did not compute. A client reads
`DetectionResultType` identically either way.

**The agent's eyes.** `tools/Opc.Ua.Mcp.Vision` adds 22 `vision_*`
tools, which with the four shared connection tools makes the `vision`
profile 26; `vision_get_frame` returns the camera image as an MCP
`ImageContentBlock`, so the model looks at pixels rather than reading a
description of them. Tool profiles now compose — `--profile
vision,robotics` yields 62 tools — so one agent can both see and act
without dragging in the full 136-tool catalogue.

**The cell.** `samples/Robotics/BinPickingCell` follows the spec's own
Robotics-Vision Addendum: the `world → robot_base → flange →
gripper_tcp` frame tree with `camera_eih` on the flange, the `HandEye`
extrinsics and the `Intrinsics612x512` intrinsics — the addendum's
2448×2048 calibration scaled to the 4×4-binned grid the camera actually
delivers. `samples/Robotics/BinPickingClient` hosts the composed MCP
catalogue and optionally the viewer.

**Documentation.** `docs/Vision.md` (~800 lines) covers the model,
hosting, the build context, every topology builder, both perception
paths, feedback, the MCP profile and the limitations; linked from
`docs/README.md`, with the profile table in `docs/McpServer.md` and
READMEs for both samples.

## Evidence, not assertions

Each of these was measured on a running system rather than assumed:

| Claim | Evidence |
|---|---|
| The camera sees the bin | 612×512 frame with the bin and all five
parts in view — red `(212,47,47)`, green `(61,193,71)`, blue
`(54,85,218)`, yellow `(215,196,58)`, orange `(209,119,55)` |
| An agent can act on what it sees | Over MCP, `vision_get_frame`
returns a 612×512 PNG that decodes from base64 to 1,254,051 bytes, the
descriptor beside the detections says 612×512, and all five
`BoundingBox2D` centres land **inside** the frame on the pixel colour
their own detection claims |
| The geometry is right | A detection composed `camera_eih → world`
lands on the authored position, residual **0.0000 m** — on both the
on-server and off-server paths |
| The detector tracks the world | Placing a part drops the next scan
from 5 detections to 4, with that part absent |
| The robot obeys the agent | Scripted run took command authority and
completed a pick and a place, both `Succeeded` |
| Tool catalogues are honest | Counted from a running server: vision 26,
robotics 40, `vision,robotics` 62, full 136, **zero duplicates** |
| Every node is browsable by NodeId | Eight representative NodeIds —
both folders, a pipeline, a frame, the sensor, its Calibrations folder,
the HandEye calibration, the Media folder — all `Good` |

That tool-count check matters because the profile tests collapse names
into a `HashSet` and *cannot see* a duplicate registration — so the new
tests count registrations, not names.

## Things that were wrong, and are not now

Writing the tests found three defects of one kind — code that answered
instead of refusing. A zero-norm quaternion was silently rewritten to
identity, so a caller with an all-zero orientation got a confident wrong
grasp pose. `SubmitCorrection` rewrote a null `ResultId` to empty and
called the sink anyway. A bad `StageIdentifier` **killed the host
process** inside native `UsdStage.Open`, via an exception .NET cannot
catch. All three now refuse loudly and are pinned by tests.

**Nodes that existed but could not be reached.** The node manager
indexes the Vision root before configurators run, so everything the
fluent builder grafted on afterwards — both folders, the pipelines with
their Results and Feedback, the frames, the sensors with their optics,
calibrations and media endpoints — was never added to the index.
Browsing *forward from a parent* worked, because that walks
`NodeState.Children` in memory; browsing any of those nodes *by its own
NodeId* returned `BadNodeIdUnknown`, which is how an ordinary client and
the MCP discovery tools navigate. Registration is now deferred and
flushed after each configurator. The first fix covered only the DI path
and left the documented non-DI fallback broken in exactly the same way,
so `ConfigureVisionAsync` now exists and registers what it builds.

That defect survived a green suite because every test browsed children.
The new tests assert by NodeId, and were checked against the broken code
— with the flush removed, they fail.

**Every Method was uncallable.** The Server passed 426 unit tests while
not one of its Methods could be invoked over a real session —
`RunInference` returned `Bad_TooManyArguments`, and so did every other
Method that takes arguments, which is all of them but `StartContinuous`
and `Stop`. Three independent faults, each sufficient on its own: the
Method nodes were never created (they are Optional children, and the
dispatcher guards every attachment with a null check, so it silently
attached nothing); nothing declared the arguments, so the stack
concluded none were expected; and `MethodDeclarationId` pointed at a
synthesised NodeId rather than the NodeSet declaration a client calls
with, so the lookup missed the instance Method entirely. The builder now
creates the Methods, the `Results` folder and the `Feedback` object when
a provider or sink is configured, declares every signature, and names
the right declaration.

Unit tests could not have caught this: they invoke the handler delegates
directly and never go through `MethodState.Call`. It took an end-to-end
test over a real session. Relatedly, children created by the generated
`CreateOrReplace` helpers carry no `ReferenceTypeId`, so nothing could
reach them — fixed once in the build context rather than at the several
dozen call sites.
**And one where I was wrong.** Earlier in this branch I reversed my own
agents' decision and made `SubmitDetections` accept an empty detection
set, reasoning that "I looked and the bin is empty" is a correct
observation and refusing it forces a correct agent to invent a
detection. The reasoning is sound; it is also an argument *against* the
specification rather than an implementation of it. §9.5 is normative and
explicit — its StatusCode table lists `Bad_InvalidArgument` for
"`Detections` empty; or `SubmitCorrection` supplies both or neither
corrected array".

Worse, **none of §9.5's argument rules were enforced anywhere** — the
dispatcher forwarded every submission straight to the feedback sink, so
conformance depended on whichever sink a host installed. They are Server
obligations, so they now live in the dispatcher, ahead of the sink,
proven by strict mocks that would throw if the sink were consulted. The
usability problem is real and does not go away by conforming, so it is
raised where it can be fixed:
[opcua-drafts#70](https://github.com/marcschier/opcua-drafts/issues/70).

## Tracking the updated drafts

The Vision, Robot Intent and AI Model Management NodeSets on
`opcua-drafts` `main` have moved, partly because of feedback this branch
raised. All three are re-vendored byte-identically — verified by
comparing git blob hashes against the upstream files rather than by eye
— and the implementations follow.

**Two statements that were previously inexpressible now have a wire
representation.** `SubmitDetections` takes `SceneIsEmpty` and
`SubmitCorrection` takes `RetractAll`, so an agent can report "I
examined this frame and there is nothing in it" — the terminating
condition of the bin-picking task — and can retract a false positive by
correcting a result down to nothing. Both are checked in both
directions, because the flag is exactly what separates a deliberate
empty observation from a lost payload: an empty array without the flag
is refused, and the flag with an array attached is refused as two
contradictory claims about one frame. Implemented in the dispatcher, the
client, the MCP tools the agent drives, and the sample cell.

Also absorbed: `LampType` and `LightingMode` became enums (§66),
`ProfileName` became `DefaultProfileName` on the endpoint (distinct from
the `ProfileName` a caller passes to `GetStreamEndpoint`, which keeps
its name), AI `Invoke`/`InvokeAsync` gained `PayloadUri` under the same
exactly-one rule, and AI `ListModels` gained a `ContinuationPoint` —
because `MaxResults` alone puts everything past the bound permanently
out of reach.

**OpenUSD is on `0.9.0-alpha`**, verified on the running cell rather
than by restore alone: D3D12 backend, 612×512 frame, the bin and all
five parts in view and detected — the same result `0.8.0-alpha`
produced.

The one local workaround that survives is `VisionMethodArguments`, and
its reason has changed rather than gone away: the builder materialises
these Methods as Optional children through `CreateOrReplace`, which
constructs the state object directly and never runs the generated
factory that now carries the signatures. Checked rather than assumed —
removing the declarations fails five of the eight
`VisionMethodSurfaceTests`.

## Review feedback

Three threads, all addressed in `0fe2803a3`:

- **The AI Model Management work is now a library family, not a
sample.** `src/Opc.Ua.AI` (model), `.Inference` (`IInferenceBackend` and
backends), `.Server` (node manager) and `.Client` (discovery, reads,
calls, artefact transfer), in the same shape as the Robotics and Vision
families; the samples become `samples/AI/ModelManagementServer` and
`ModelManagementClient`. The client library needed real work rather than
relocation: its browsing surface was `private` inside the sample's
scenario runner, so moving the file alone would have produced a library
nobody could call.
- **No cloud-vendor SDK is referenced anywhere.** Inference goes through
`Microsoft.Extensions.AI` — an `IChatClient` is implemented by hosted
services and on-device runtimes alike, which is exactly the property
clause 8.1 asserts. `Azure.Identity` is gone: workload identity is not
an Azure feature, every platform projects a token into a file and each
SDK reads that file behind its own API, so the resolver reads it
directly. The comment claiming `Microsoft.Extensions.AI` would force a
`System.Text.Json` bump was stale — it pins 10.0.10, which this
repository already centralises on.
- **`BinPickingCell` and `BinPickingClient` moved into
`samples/Robotics/`**, which is where they belonged: the cell was
already linking the arm, its kinematics and both USD assets out of
`IntentEnabledRobot`.

## Upstream

Work that belonged elsewhere went elsewhere rather than being worked
around locally:

- **`openusd-dotnet`
[#13](https://github.com/marcschier/openusd-dotnet/pull/13)** — merged
and shipped in `0.8.0-alpha`. `SilkFrameCapture.Capture` rendered only
the first capture of a session and silently returned a blank frame for
every one after it. Also filed
[#14](https://github.com/marcschier/openusd-dotnet/issues/14) (no
camera-by-prim API) and
[#15](https://github.com/marcschier/openusd-dotnet/issues/15) (skipped
tests reported as passed — which fooled me for several runs). Both are
fixed; this branch takes `0.8.0-alpha` and deletes two workarounds,
including 143 lines of hand-rolled projection maths.
- **`opcua-drafts`
[#66](https://github.com/marcschier/opcua-drafts/issues/66)–[#69](https://github.com/marcschier/opcua-drafts/issues/69)**
— a close read of the spec produced 22 candidate ambiguities; 12 were
discarded as misreadings with clause citations and the remaining 10
filed. One is concrete: five members exist in the NodeId CSV that no
clause documents.
- **`opcua-drafts`
[#70](https://github.com/marcschier/opcua-drafts/issues/70)** — §9.5
could not express an empty observation or a false-positive retraction.
**Adopted**, with the explicit-flag resolution argued for:
`SubmitDetections` gained `SceneIsEmpty`, `SubmitCorrection` gained
`RetractAll`, and the corrected-array rule relaxed from *exactly one* to
*at most one*.
- **`opcua-drafts`
[#71](https://github.com/marcschier/opcua-drafts/issues/71)** — the
Vision NodeSet browse-named all 13 `InputArguments` / `OutputArguments`
Properties in the Vision namespace rather than the base namespace, so a
stack could not find them and every Method in the specification was
uncallable. **Fixed**; this branch now tracks the corrected artefact.

## The defect underneath it all

The end-to-end suite was removed earlier in this branch because nine of
its
fourteen tests failed on one symptom: a client could not open a
pipeline's
`Feedback` object or enumerate its `Results`, even though browsing the
same
parent listed both. Restoring it meant explaining that, and the
explanation
was not in Vision.

`RelativePathElement` initialised **`IsInverse` to `true`**. A caller
that
sets a `ReferenceTypeId` and a `TargetName` — which reads as *"the child
reached by this Reference"* — was therefore asking the Server for the
**inverse** Reference, and got `Bad_NoMatch` with nothing in the request
to
suggest why.

`ObjectTypeClient.ResolveChildNodeIdAsync` is such a caller, and it is
what
**every source-generated Optional-child accessor in the stack** is built
on
— the accessor whose own documentation cites
`AlarmConditionTypeClient.GetShelvingStateAsync`
as an example. Vision is merely where it surfaced, because Vision puts
two
Optional children on the path an off-Server agent must take. The sibling
helper in `StateMachineTypeClientExtensions` already set `IsInverse =
false`
by hand, which is the shape of a trap rather than a default.

The default is now forward, `ResolveChildNodeIdAsync` says so
explicitly,
and the existing test that had recorded `true` as *expected* now pins
`false` with the reasoning. Of the forty `RelativePathElement`
construction
sites in the tree, that accessor was **the only one relying on the
default at
all** — every deliberate caller already set it.

Two further defects were found underneath it, both real and both fixed:

- The generated `CreateOrReplace` helpers construct a child state object
directly and leave **`TypeDefinitionId`** unset as well as
`ReferenceTypeId`.
A child referenced by nothing cannot be browsed; one with no type
definition
is a malformed Object that a client filtering by type silently skips —
which
  is exactly what `EnumerateResultsAsync` does. Normalisation moved to
`VisionNodeManager`, so it also covers the case the builder cannot see:
a
result published **at runtime** by an inference provider, long after the
address space was built. That path produced results a client could list
but
  not read.
- `Opc.Ua.AI` shipped without an `AssemblyInfo`, so the solution built
with
  six `CA1014` warnings.

I had initially "fixed" this in the Vision client with Browse-based
fallbacks,
on the strength of a probe that appeared to show
`TranslateBrowsePathsToNodeIds`
failing even for `Server → ServerStatus`. That probe was wrong: it used
an
unqualified `ReferenceTypeIds`, which inside a `Opc.Ua.Vision.*`
namespace
binds to *Vision's* `ReferenceTypeIds` and yields a nonsense NodeId.
Chasing
that to the end is what turned up the real cause. **The fallbacks are
gone** —
they would have hidden a stack-wide bug behind a Vision-shaped
workaround, and
one of them matched on browse name while ignoring the namespace index.

`tests/Opc.Ua.Vision.Intent.Tests` is restored and back in `UA.slnx`,
passing
**14/14** on its own merit rather than through a client-side workaround.
A
registration test now pins the pipeline's `Feedback` and `Results`
children,
which nothing covered before.

## Running it, and what that found

The demo's premise is that a language model **looks at the bin and
reasons
about what it sees**. Running it end to end showed it could not, for
reasons
no test covered, because every one of them lived between components.

**The sample did not compile.** Two `CS8604` nullable errors with
`TreatWarningsAsErrors`, so neither the cell server nor the demo could
be
started at all. Worth recording that my first explanation was wrong: CI
*does*
build this project - the Linux leg's `net10.0` pass compiles it,
log-confirmed -
so this is not a coverage gap in the workflow, and no workflow change
was made.

**`Pick` and `Place` never moved the arm.** They were a delay plus a
gripper
action, so the operations reported `Succeeded` while nothing travelled.
They now
solve IK once and interpolate in joint space. **And the parts never
moved**: the
arm swung but the bin stayed full, because nothing tied the held object
to the
world state. The connector now creates 11 monitored items where it
created 6,
and a scripted run delivers `SeqNo=151` across 10 messages where it
delivered
`SeqNo=3` across 1.

**The frame was smuggled through a string field.** The media provider
put a
base64 *data URI* of the PNG into `VisionImageReferenceDataType.Uri` - a
field
meant to be a *reference*, while the bytes were already returned in the
inline
`ByteString`. Every response therefore shipped the image twice, and a
1,311,400-byte PNG became a 1,748,536-character string against a
`MaxStringLength` of 65,535: **26.7x over**. That is why raising
`MaxByteStringLength`, `MaxArrayLength` and `MaxMessageSize` never
helped - none
of them govern a `String`. Separately the MCP tool assigned raw bytes
where
`ImageContentBlock` requires base64, so the wire carried
`"data":"�PNG..."` -
every non-UTF-8 byte replaced by U+FFFD, destroying the image and
inflating the
response to 6.8 MB.

**The camera was aimed at nothing.** The arm's home pose, the flange
scan pose
the Vision model declared and the joint angles in the USD stage were
three
independent claims about where the camera was, and they disagreed - the
declared
flange orientation pointed the view 86 degrees away from the projection
camera.
Solving them as one thing exposed two further constraints that are easy
to miss:
the camera has to sit off the tool axis or it photographs its own
gripper, and
the IK branch has to be elbow-back or a link parks under the camera and
fills the
frame with the arm's own upper arm. A third was a regression this branch
introduced and `Opc.Ua.Robotics.Tests` caught - aiming a straight-down
camera
from a point on the base's own X-Z plane puts the wrist on the J4/J6
singularity, so every motion away from home fails to solve. A 15-degree
camera
roll, free because the camera still looks straight down, gets 25 degrees
clear,
which is the margin the poses before this branch had.

**The frame and the detections were different images.** The sensor
declared
2448x2048, the clip endpoint 1280x1024, and the renderer produced
640x512 - not
even the same aspect ratio. The ground-truth detector projects through
the
declared intrinsics, so its boxes lived in 2448x2048 space while an
agent was
handed a 640x512 picture: *"pick the red cube you can see"* arrived with
coordinates that pointed off the image. Everything now agrees at
612x512, an
exact 4x4 bin of the native sensor with the intrinsics scaled to match;
the
native size stays in the model and serial number, where it describes the
hardware rather than the image.

**`LatestClip` was created and never written**, so it reported
`Bad_NoDataAvailable` for the life of the Server and a consumer
following the
model - read the published frame, call the method only if there is none
- never
got a frame. The dispatcher now publishes a clip it has just encoded,
for every
Vision server rather than this sample alone.

One genuine API gap turned up on the way: `OpcUaServerOptions` exposes
`MaxByteStringLength`, `MaxArrayLength` and `MaxMessageSize` and **no
`MaxStringLength`**, so a Server that legitimately needs a long string
could not
raise the limit through the hosting API at all. Added, with tests. It is
not the
fix for anything above - that was a design bug - but the missing knob
was real.

## Not finished

- **Two projects sit below the repository's 80% line coverage.**
`Opc.Ua.Vision.OpenUsd` is at 71.1% — what is left only executes with a
real OpenUSD stage and plugin tree, which is not on every build agent.
`Opc.Ua.AI.Inference` is now at **86.7%**, up from 12.9%: the code this
branch *wrote* is covered by 25 tests, and `RestChatCompletionsBackend`
— previously the whole of the shortfall — is covered by 18 more against
a stubbed `HttpMessageHandler`, exercising success, refusal, throttling,
retry-after, timeout and cancellation without a network. Everything else
clears the bar — `Opc.Ua.Vision.Server` 92.1%, `Opc.Ua.AI` 91.4%,
`.Vision.Client` 88.1%, `Opc.Ua.Vision` 85.7%, `Opc.Ua.AI.Server` 80.1%,
all measured with coverlet. The CI coverage gate reports itself as
advisory and non-blocking.
- **`SamplesCollected` is not counted here, and `docs/Vision.md` now
says so.** Section 9.4 requires a Server to count a negative example
(`SceneIsEmpty` / `RetractAll` carrying a `GroundTruthLabel`) exactly as
it counts one carrying geometry. `VisionNodeManager` does not, and
structurally cannot: `SamplesCollected` is a property of
`LearningJobType`, which the *AI Model Management* companion defines,
and Vision reaches the job through a `NodeId` value rather than a
Reference **precisely so this model takes no dependency on the model
that defines it**. What the Server does guarantee is that the negative
example survives the hop intact — both flags are carried verbatim to
`IVisionFeedbackSink` — so a host that binds a learning job has
everything it needs to satisfy the clause on the counter it owns. Stated
in the limitations rather than left implied.

## Related Issues

Was stacked on #4195, now merged. No tracking issue yet for the Vision
implementation itself — happy to open one if you would like the design
recorded as an ADR before this goes further.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage. — *Types 8562, Server 4072,
Client 2123, InformationModel 1063, Robotics 540, Tools 466, Vision 442,
AI 74 and the restored Vision+Intent end-to-end suite 14/14, all green
on net10.0. Only `.OpenUsd` (71.1%) is below the 80% bar — see Not
finished.*
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings. — *`dotnet build UA.slnx -c Release`: 0 errors, 0
warnings.*
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed. — *net48:
Types 8555, Client 2126, Vision 385 green. Two net48 Server tests fail
(`CreateUserManagementSeamBindsTheModelToTheServerAsync`, and
`DurableDataValueQueueVerifyReferenceBatchingAsync` only under parallel
load); both were confirmed **pre-existing** by re-running them with the
`IsInverse` change reverted, which fails identically.*
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings. — *The net48 build legs failed because the
restored end-to-end project used `ValueTask.FromResult` /
`string.Create`, which do not exist on .NET Framework; fixed in
`fb57522da` and verified building on every TFM.
`DisposeDrainsHeldConnectionCallbackBeforeListenerDisposal` failed once
on the Ubuntu Client leg — a 13 ms timing-sensitive reverse-connect
disposal test that passes locally 2123/2123 and touches no browse
paths.*
- [ ] I have addressed **all** PR feedback received.
## Typed Vision-guided Robotics MCP workflows

The branch now also makes the demo workflow first-class in the Full MCP
profile:

- replaces stringified Robotics intent and mission inputs with typed
request schemas and exact name-or-NodeId selectors;
- adds bounded operation/mission paging, stable step-to-operation
identity, retained mission discovery, and `robotics_wait_mission`;
- makes `vision_run_inference` return bounded typed detection,
inspection, or segmentation summaries in one call;
- adds same-session `robotics_vision_pick` to select a detection and
submit Pick or Pick/Place work without implicitly taking authority,
retrying, cancelling, or waiting; and
- starts Publish workers for classic subscriptions so an independently
launched OpenUSD viewer receives live robot and part updates.

The migration guide documents the intentionally breaking MCP
request-schema changes.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 1dab1302-19c5-4a9b-a50c-d97d389713aa
Copilot-Session: a248a589-9a20-4372-868e-5d347e57001b
Copilot-Session: 99d1ab42-f83a-41ab-bf3e-85bf81fadace
Copilot-Session: bcbc8ac9-5abd-42a8-8bac-e10533790e2e
2026-08-29 19:34:15 +02:00
Marc SchierandCopilot 3713641479 Throttle client publish worker on undeliverable publish responses (+ CodeQL OOM fix) (#4121)
# Description

Fixes a busy-spin in the client publish worker that crashed the
**net48** CI test host (e.g. [build
16092](https://opcfoundation.visualstudio.com/opcua-netstandard/_build/results?buildId=16092&view=results),
`Test Release` reported *"The active test run was aborted. Reason: Test
host process crashed"* on
`SubscriptionManagerTests.PublishWorkerDefersDeletingUnknownSubscriptionWhileCreationIsPendingAsync`).

It also carries a small, self-contained CI fix for the repository-wide
CodeQL out-of-memory failure (see the last section).

## Root cause

In `SubscriptionManager.PublishWorkerAsync`, a publish response whose
`SubscriptionId` does not resolve to a subscription the manager owns set
`moreNotifications = true`. That flag **skips the ack-wait throttle**,
so the worker immediately re-issues `Publish`.

The condition is *persistent* — the server keeps answering with the same
undeliverable identifier — so the worker spun with **zero delay**,
logged at `Information` level on every iteration, and in the orphan
branch issued `DeleteSubscriptions` for the very same subscription on
every single response. With a transport that completes synchronously the
loop additionally never released its thread pool thread.

Measured on the unmodified code, for a single 485 ms test:

| Metric | Before |
|---|---|
| `DeleteSubscriptions` calls for one orphan | **16,500** |
| "deferred unknown subscription" log lines | **4,296** |
| TRX produced by that one test | **4.86 MB** (47% of the whole
2,124-test assembly) |
| Peak test host working set | ~528 MB |

On a slow 2-core hosted agent the polling loops stretch out, the spin
runs far longer, and the unbounded log/allocation growth takes the test
host down.

Beyond the CI symptom this is a real client defect: against a live
server the client would hammer it with `Publish`/`DeleteSubscriptions`
and flood the log whenever a subscription identifier cannot be resolved.

## Changes

`src/Opc.Ua.Client/Subscription/SubscriptionManager.cs`

- Undeliverable publish responses (retired identifier, identifier still
pending creation, or genuine orphan) now **always throttle** through a
new `DelayUnresolvedSubscriptionAsync` — an escalating, bounded backoff
(20 ms doubling to a 250 ms cap) — instead of republishing immediately.
- After deleting an orphan, its identifier is passed to
`RetireSubscriptionId`, so responses already in flight (or emitted
before the delete takes effect) are ignored rather than triggering
another delete. **One delete instead of thousands.**
- The deferral message is logged once per run of the same unresolved
identifier instead of once per response.
- The unresolved-response counters reset as soon as a response is
dispatched successfully.


`tests/Opc.Ua.Client.Tests/Subscription/Fakes/FakeSubscriptionManagerContext.cs`

- The call recordings were plain `List<T>` appended to from
publish-worker threads while the test thread read them. They are now
guarded by a `System.Threading.Lock` and exposed as snapshot
`IReadOnlyList<T>` getters.
- Added `DeleteCallsCount`, a locked count accessor, so polling wait
conditions do not allocate a snapshot per iteration.

`tests/Opc.Ua.Client.Tests/Subscription/SubscriptionManagerTests.cs`

- `PublishWorkerThrottlesWhileSubscriptionIdIsUnresolvedAsync` — bounds
the publish count over a 500 ms window; fails loudly on the old code.
- `PublishWorkerDeletesUnknownSubscriptionOnlyOnceAsync` — asserts
exactly one `DeleteSubscriptions` call for an orphan.

## Results

| Metric (single test) | Before | After |
|---|---|---|
| Deferred log lines | 4,296 | 3 |
| `DeleteSubscriptions` log lines | 16,500 | 3 |
| TRX size | 4,856,749 B | 6,466 B (**750×** smaller) |

The full-assembly TRX dropped from 10.30 MB to 4.92 MB.

No public API change; behaviour change is limited to the
undeliverable-publish-response path.

## CodeQL out-of-memory fix (`.github/workflows/codeql-analysis.yml`)

The CodeQL job has been failing repository wide — on `master` and on
every open PR — with:

```
CodeQL is out of memory. Try running CodeQL on a larger runner (hosted or self-hosted).
Error running analysis for csharp: ... codeql database interpret-results --threads=4 ...
Exit code was 99
```

The CodeQL step builds `UA.slnx` without `CustomTestTarget`, so
`targets.props` falls through to its default and multi-targets up to
**six** frameworks (`net472`, `net48`, `netstandard2.1`, `net8.0`,
`net9.0`, `net10.0`). CodeQL therefore extracts every source file once
per framework. The same multiplier applies to source-generated code,
which `EmitCompilerGeneratedFiles` materializes on disk —
`Opc.Ua.Core.Types` alone emits **52 MB** of generated C# for a *single*
framework. The database and source archive grew until
`interpret-results` exhausted the runner's memory.

- Pin the CodeQL build to `-p:CustomTestTarget=net10.0` so every source
file is extracted once instead of ~6×. Verified locally: `UA.slnx`
builds with **0 errors** under that property.
- Limit the analyze step to `threads: 2`, bounding the peak memory of
the step that failed.

This is unrelated to the publish-worker fix and is happy to be split out
if maintainers prefer.

## Review feedback addressed

- Snapshot properties are read once into a local before asserting, so
two reads cannot observe different snapshots.
- Wait conditions poll the new non-allocating `DeleteCallsCount` instead
of `DeleteCalls.Count`.
- The sync root is declared as the fully qualified
`System.Threading.Lock`. An `object`-typed sync root was **not** used:
repository coding standards forbid it, and
`Opc.Ua.Types/Polyfills/System.Threading.cs` already backports a public
`System.Threading.Lock` for every TFM below net9.0.

The branch was rebased onto current `master` (`8a10139b8`).

## Related Issues

- No tracked issue; reported via the failing `Test Release` (net48) leg
of build 16092.

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation. _(Internal behaviour
fix, no API or documented-behaviour change.)_
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings. _(0 warnings, 0 errors on net48 and net10.0.)_
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
  - `Opc.Ua.Client.Tests` **net48** (CI filter): 2,124 passed, 0 failed
  - `Opc.Ua.Client.Tests` **net10.0**: 2,121 passed, 0 failed
- `Opc.Ua.Subscriptions.Tests` **net10.0** (integration): 602 passed, 0
failed
- `SubscriptionManagerTests` fixture run 5× on net48: 36/36 every run
(no flakiness)
- [x] I have addressed **all** PR feedback received.
- [x] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 6615d151-e4af-43c7-8a32-4531842e7461
2026-08-03 09:50:41 +02:00
Marc SchierandCopilot 636912bd4c Harden subscription retirement after #4114 and refresh the client namespace table on model change (#4115)
# Description

Two things, both surfaced by the live NodeManager registration work in
#4094.

> **Rebased on #4114.** Upstream landed #4114 (`cc4667d0b`) while this
PR was open; it fixes the
> same #4113 root cause. `origin/master` is merged in and the conflicts
were resolved **in favour of
> the upstream API shape** — `CompleteAsync(IMessageProcessor, uint
subscriptionId, ct)` with the
> last known server id passed as an argument. The
`IMessageProcessor.LastServerId` member this
> branch had added is dropped again. What remains here is the orthogonal
hardening #4114 does not
> cover, plus all of the #4100 work.

## 1. Remaining subscription-retirement hardening (on top of #4114)

#4114 fixed the id-collision itself. Three related holes in the same
paths are still open:

- **Retirement was not atomic with removal.** `RetireSubscriptionId` is
now called *under*
`m_subscriptionLock` from both `CompleteAsync` and
`RemoveSecondaryPartitionAsync`. `GetById`
resolves incoming publish responses under the same lock, so a worker
could otherwise observe the
subscription as removed while its id had not yet reached the retired-id
ring — and send a
redundant `DeleteSubscriptions` for an already-retired id.
`RemoveSecondaryPartitionAsync` did not
  record the retired id at all.
- **The retired-id ring was far too small.** `kMaxSubscriptionHistory`
10 → 256, so subscription
  churn cannot evict live history.
- **The orphan delete was unguarded.** The publish worker no longer
sends `DeleteSubscriptions` for
an unresolved id while any subscription is still awaiting its id. A
publish response can overtake
the `CreateSubscription` continuation that assigns the id, and deleting
in that window kills a
healthy subscription. Leaving a genuine orphan alive until its lifetime
expires is the safe
  trade-off.
- **`PublishControllerAsync` lost resize signals.** It re-created its
`AsyncAutoResetEvent` waiter on
every loop iteration; the abandoned waiter stayed enqueued and swallowed
a later `Set()`, so the
publish worker pool stopped resizing. This is a second, latent
starvation path independent of the
id collision. The wait is now created once and only re-armed after it
completes.

## 2. Managed client does not refresh the namespace table on model
change (#4100)

`NodeManagerLifecycle.NotifyCommittedChangeAsync` updates
`NamespaceArray`, bumps `UrisVersion`, and
then reports a **`BaseModelChangeEvent`** — an event shape that carries
no `Changes` payload. The
client tracker *did* observe it and cleared the `INodeCache`, but it
held only an
`IStreamingSubscription`, an `INodeCache` and an `ILogger`, so nothing
could re-read the namespace
table. A tracking client therefore resolved NodeIds from a namespace
added by a live NodeManager
registration against a stale `NamespaceUris` table.

- **New `INamespaceTableRefresher`** (`NamespaceUris` +
`FetchNamespaceTablesAsync`). The member
signatures match what `Session` and `ManagedSession` already expose, so
both satisfy the interface
without any new members. `ISession` is deliberately left untouched —
moving its members onto a base
  interface would be a binary break for 1.5.378 consumers.
- **`ModelChangeTracker`** takes the refresher as an optional *trailing*
constructor argument, which
keeps every existing call site source-compatible and makes `null` the
opt-out. A refresh runs when
the event carries no per-node detail, when an affected node is
`Server_NamespaceArray`, or when an
affected namespace index is beyond the client's table. It runs
**before** the cache is invalidated
and before `ModelChanged` is raised, so subscribers that re-browse from
the handler already see the
  new uris. A failing refresh is logged and swallowed.
- **`ModelChangedEventArgs.NamespaceTableRefreshed`** reports the
refresh to applications.
- **`ManagedSession.EnableModelChangeTrackingAsync`** wires the session
in, so opting into tracking
is all an application has to do — no new option, no change to the
positional `CreateAsync`
  signature.
- **`ModelChange.TypeDefinition`** changes from `NodeId?` to `NodeId`.
`NodeId` is a readonly struct
implementing `INullable` and must not be wrapped in
`System.Nullable<T>`; use `NodeId.Null` and
`IsNull` instead. The type is 2.0-preview only (absent from 1.5.378),
and the only producer is the
tracker itself, which already assigns a non-null `AffectedType`. Per
review feedback the type is
also now a `readonly record struct`, matching `DataValueChange` /
`EventNotification`.

## Tests

Every new regression test was run against a temporarily re-introduced
defect and **fails** there:

| Test | Covers |
|---|---|
|
`CompleteAsyncRetiresOnlyTheCompletedSubscriptionWhenOthersArePendingCreationAsync`
| retire-by-identity (also guards #4114's fix) |
| `CompleteAsyncRemembersRetiredServerIdAfterIdWasResetAsync` |
retired-id history |
|
`PublishWorkerDefersDeletingUnknownSubscriptionWhileCreationIsPendingAsync`
| orphan-delete guard |
| `PublishControllerKeepsResizingAfterWorkersExitAsync` |
publish-controller signal loss |
| `ConcurrentAddAndCompleteRetireOnlyCompletedSubscriptionsAsync` |
parallel add/retire registry integrity |
| `ConcurrentSubscriptionChurnNeverStarvesASubscription` (integration) |
#4113 repro against the reference server |
| 7 × `ModelChangeTrackerTests` namespace-refresh cases | each trigger,
no-trigger, throwing refresher, `null` refresher, ordering |
| `LiveNodeManagerAddRefreshesTheClientNamespaceTable` (integration) |
#4100 repro — times out without the wiring |

`FakeMessageAckQueue` records both the completed id (upstream's
assertions) and the completing
instance (the identity assertion in `MessageProcessorTests`), so neither
side's coverage was lost in
the merge.

Results after merging `origin/master`:

- `Opc.Ua.Client.Tests` — **2119/2119** pass on net10.0; the new
`ModelChange` and
  `SubscriptionManager` fixtures also pass on **net48**.
- `Opc.Ua.Subscriptions.Tests` churn + coverage fixtures — **28/28**
(net10.0); churn fixture also
  passes on net48.
- `Opc.Ua.Server.Tests` `NodeManagerLifecycle*` — **49/49** on net10.0;
the new fixture also passes
  on net48.
- No new analyzer warnings; only the three pre-existing `CA1873` hits in
`NodeCacheResolver.cs` and
  `ClassicSubscriptionEngine.cs` (untouched files) remain.

## Documentation

- `docs/ModelChangeTracking.md` — new **Namespace table refresh**
section with the trigger table,
updated `ModelChangedEventArgs` / `ModelChange` snippets, updated
manual-construction snippet, and
  a quick-reference row.
- `docs/NodeManagerRegistration.md` — client-side half of the
**Namespaces** section.

No `docs/migrationguide.md` entry: every changed type is either
`internal` or 2.0-preview-only.

## Related Issues

- Fixes #4100
- Follow-up hardening for #4113 (closed by #4114)
- Related to #4094, #3993

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: e22f9b3c-1682-40bd-8b72-31a11352fa2c
2026-07-30 12:17:00 +02:00
dpseandMarc Schier cc4667d0b5 Complete client subscriptions by identity instead of id (#4114)
# Description

Completes subscriptions by passing `IMessageProcessor` and last known
server subscription id to prevent incorrect subscription removal when
multiple subscriptions with id 0 exist.

## Issue

During calls to `SubscriptionManager.CompleteAsync`, the subscription
manager looked up the subscription entry to remove by the passed
subscription id. But newly created subscriptions not yet having received
an id from the server have their id set to 0, meaning that disposing an
unrelated subscription also with id set to 0 could remove the wrong one
(as there can exist multiple subscriptions with the same zero-id), which
in turn could lead to the id no longer being resolved, and the publish
worker treating it as unknown. Deleted subscriptions also have their id
reset to zero, which could potentially clash as well.

## Fix

- Internal interface `IMessageAckQueue` is changed so that
`CompleteAsync` also takes `IMessageProcessor` as an argument.
- `MessageProcessor` stores the known server id (if set) and passes
itself along with that id to `CompleteAsync`.
- With the `IMessageProcessor` argument, `SubscriptionManager` no longer
needs to look up subscription by id and therefore removes the correct
subscription.
- Additionally, `SubscriptionManager` receives the non-zeroed server id
and no longer enqueues zero-value ids to the subscription history.

## Related Issues

- Fixes #4113 

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [ ] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.

---------

Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
2026-07-30 09:33:50 +02:00
Marc Schier 39991bfea1 Harden managed subscription recreation and reapply (#4065)
## Summary

- Makes managed subscription recreation generation-safe by quiescing
publish ingress, draining in-flight requests, retiring queued messages
and acknowledgements from the old server-side generation, then
recreating monitored items as one serialized operation.
- Exposes `RecreateAsync` on `ISubscription`, rejects recreate/dispose
reentrancy from notification callbacks, preserves the active generation
when server-side deletion fails, and coordinates disposal with an
in-flight recreate.
- Aggregates logical subscription recovery state across partitions and
adds pending/reapply APIs so monitored items can be deterministically
re-created after model or configuration changes.
- Initializes the Quickstarts Boiler logger with `NullLogger` so
simulation updates remain safe before a logger is assigned.
- Keeps the new logical recovery test compatible with net48.

## Review follow-up

- Documents the `RecreateAsync` callback-reentrancy and disposal
exceptions on the public interface.
- Extends generation-retirement coverage with a 1,024-message stale
burst and verifies that only ordered current-generation callbacks are
delivered.
- Proves manager disposal cancels a cancellation-aware operation holding
publish quiescence and waits for the gate to release safely.
- No runtime timeout or blanket channel drain was added: the quiesced
production delegate is internal and cancellation-aware, while
unconditional draining could discard or reorder current-generation
messages arriving through direct ingress.

## Validation

Current head: `edb4a75145c8b03bd03da15eb71327e3bffda091`.

Review follow-up validation on the current head:

- `Opc.Ua.Client` and `Quickstarts.Servers` build successfully for
net472, net48, netstandard2.1, net8.0, net9.0, and net10.0.
- focused `SubscriptionTests` and `SubscriptionManagerTests`: 72 passed
on net10.0 and 72 passed on net48.

The runtime implementation is unchanged from
`7b944ac68616e2d6c0595957c65179f86e78a637`, which passed:

- net10.0 `Opc.Ua.Client.Tests`: 1,974 passed.
- net10.0 `Opc.Ua.Sessions.Tests`: 738 passed, 379 skipped.
- net10.0 `Opc.Ua.Subscriptions.Tests`: 601 passed, 6 skipped.
- focused net48 managed-subscription tests: 122 passed.
- win-x64 Native-AOT publish succeeded; subscription, monitored-item,
and Boiler AOT cohorts: 14 passed.
2026-07-23 09:54:26 +02:00
Marc Schier 7cec2d614d Move repository files to the consolidated layout 2026-07-16 06:25:54 +02:00