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Author SHA1 Message Date
romanett 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
Marc Schier 168b3de353 Replace the RequestManager AsyncLocal guard with an explicit operation context (#4163)
# Description

`RequestManager` tracked whether the calling flow was serving a Client
request in a `private readonly AsyncLocal<bool> m_inServiceDispatch`. It
was set by a `StandardServer.ProcessRequestAsync` override and read by
`NodeManagerLifecycle`, so that a lifecycle operation (`AddAsync` /
`ReloadAsync` / `RemoveAsync`) started from inside a request fails fast
with `InvalidOperationException` instead of draining — and therefore
waiting for — its own request.

Two problems with that mechanism, raised in review of #4093:

1. An `AsyncLocal<T>` written inside an `async` method never flows back
to the caller that awaited it, so every scope had to chain to the
previous value by hand and restore it on dispose. Subtle, and easy to
get wrong when a new entry point is added.
2. Ambient state is invisible at the call site, so the lifetime of the
mark could not be reasoned about from the code that depended on it —
especially once work is handed to a background task.

`RequestManager` also had no business carrying ambient state on behalf
of a different subsystem; its job is tracking requests for the drain.

## What changed

The guard is now an **exact identity lookup** against the request
registry `RequestManager` already maintains, and the operation is
threaded **explicitly**:

* **`RequestManager`** — `internal bool
IsExecutingRequest(IOperationContext?)` performs a reference-identity
lookup against `m_requests` under the existing `m_requestsLock`.
`m_inServiceDispatch`, `EnterServiceDispatchScope()`, the nested
`ServiceDispatchScope` class and the flag-based `IsExecutingRequest`
property are gone.
* **`StandardServer`** — the `ProcessRequestAsync` override is removed;
it existed only to open the dispatch scope.
* **`INodeManagerLifecycle`** — every member (`AddAsync` ×2 factory
kinds, `ReloadAsync` ×2, `RemoveAsync`) now takes the caller's
`IOperationContext?` directly, ahead of `CancellationToken ct =
default`. No overloads and no parallel signature are kept: the interface
is new in 2.0 and outside the 1.5.378 compatibility rule, so call sites
state their context explicitly or pass `null`.
* **`HostedNodeManagerLifecycle`** and
**`RuntimeNodeSetLifecycleExtensions`** thread the argument through;
`AddRuntimeNodeSetAsync` / `ReloadRuntimeNodeSetAsync` remain single
methods.
* **`SystemContextOperationExtensions.GetOperationContext(this
ISystemContext)`** (new, `Opc.Ua.Core`) lets a NodeManager or Method
callback hand over the operation it already received without
downcasting. It switches on `SessionSystemContext` and `SystemContext`,
the two independent roots every context derives from. No new interface
is introduced: casting the context to `IOperationContext` would not do,
because a context implements that by delegating to the operation it was
created for, so the cast yields the context rather than the operation.
* **`NodeManagerLifecycle.EnsureNotRequestCallback`** no longer consults
`ServerState`. The previous `CurrentState == Running` predicate could
let a genuinely re-entrant call slip past while the server was shutting
down; the request registry answers exactly in every state.

A NodeManager or Method callback now reads:

```csharp
await m_lifecycle.ReloadAsync(m_registration, replacement, context.GetOperationContext(), ct);
```

and a control-plane caller (hosted service, DI consumer) passes `null`.

## Behaviour

Unchanged for the case the guard exists to catch: a lifecycle call made
on behalf of an executing request is still rejected up front with the
same `InvalidOperationException` and the same message.

Two deliberate differences:

* **Improvement** — an internal `OperationContext` that was never
enrolled as a Client request is now correctly allowed through. The
boolean flag could not distinguish it from a real request.
* **Accepted trade-off** — a caller inside a request that passes no
operation is no longer detected at entry and falls back to the
pre-existing bounded `RequestManager.RequestDrainTimeout`, which already
covered any request that bypassed the service pipeline. Automatic
detection for an uncooperative caller inherently requires ambient state,
which is exactly what this change removes. Documented in
`docs/NodeManagers.md`.

## Alternatives considered and rejected

| Alternative | Why rejected |
| --- | --- |
| Delete the guard, rely only on `RequestDrainTimeout` | Turns a clear
immediate error into a multi-minute hang. |
| Infer the caller from the `CancellationToken` it passes | Works only
for the exact request token, breaks on linked tokens; ambient magic of a
different kind. |
| In-flight callback counter on `MasterNodeManager` | False positives:
rejects legitimate control-plane calls whenever any request is
concurrently dispatching. |
| Defer the drain to a background task so re-entrancy cannot deadlock |
The drains are woven into transactional commit / rollback and binding
reconciliation; deferring them breaks the transactional guarantees. |
| `Activity.Current` / `ThreadLocal` | The same ambient magic the issue
asks to remove. |

## Testing

* `RequestManagerTests` — the three `EnterServiceDispatchScope` tests
are replaced by coverage for `IsExecutingRequest(context)`: null,
never-registered, only-while-scope-open, visible across an `await` and a
background `Task.Run`, and two concurrently executing requests not
confusing each other.
* `NodeManagerLifecycleTests` — rejection from an executing request for
Add / Reload / Remove without invoking the factory, acceptance for a
context that is not an executing request, acceptance once the request
has completed, and the full callback shape
(`ServerSystemContext.Copy(operation)` → `GetOperationContext()` →
rejected).
* `HostedNodeManagerLifecycleTests` — forwarding tests for the
caller-context argument on all five members.
*
`tests/Opc.Ua.Core.Tests/Stack/State/SystemContextOperationExtensionsTests.cs`
(new) — `GetOperationContext` across both context roots and the
null-argument guard.

## Related Issues

- Fixes #4149

## 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.
- [ ] I have addressed **all** PR feedback received.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 14402d11-e540-4faa-a5cd-94881bd7ce85
2026-08-03 20:31:51 +00:00