# 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>
## Summary
- Qualify unprefixed `CreateDirectoryAsync` path segments with the
current parent namespace.
- Preserve qualified segments after cached and uncached resolution so
returned `FullPath` values
are canonical.
- Keep explicit namespace-prefix validation tied to caller input and use
the server-reported
`BrowseName` after creating a directory.
- Add unit coverage for both `createIntermediate` modes, canonical file
and directory paths, and
cached resolution.
- Add an integration regression using the reference server,
`FileSystemNodeManager`, and
`PhysicalFileSystemProvider`.
## Testing
- `Opc.Ua.Client.Tests` filesystem category on `net10.0`: 118 passed.
- `FileSystemClientIntegrationTests` on `net10.0`: 14 passed.
- `Opc.Ua.Client.Tests` filesystem category on `net48`: 118 passed.
- `FileSystemClientIntegrationTests` on `net48`: 14 passed.
Fixes#4362
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: romanett <7413710+romanett@users.noreply.github.com>
Co-authored-by: Marc <marcschier@hotmail.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
**Stack 1/5** — base `master`. Part of the #4096 split; see #4096 for
the overall picture.
## What this is
The core stack changes the Robotics, OpenUSD and Positioning work
depends on. No new projects; every change is to an existing one, so this
is reviewable without any of the companion specs.
## Contents
**`Opc.Ua.Server`**
- `FileSystem` gains a reusable `IFileDirectoryBinder` and
`IFileSystemHost`, so any node manager can serve a Part 5
`FileDirectoryType` over `IFileSystemProvider` instead of that binding
living inside one companion model.
- Entry names are validated before they reach the provider. The contract
promises forward-slash provider-relative paths but never enforced it, so
a backslash payload such as `..\..\..\Windows\System32\evil.txt`
bypassed the obvious provider-side check on Windows. Defence in depth —
the shipped `PhysicalFileSystemProvider` was already safe.
- `Location` adds a single `IGeoLocationProvider` seam so one provider
implementation serves both OPC 10000-211 GPOS and OPC 10030 ISA-95. The
two specs disagree on representation, not on content, so the difference
is a projection rather than a reason to write the provider twice. Ships
a WKT text formatter and an in-memory provider.
- `StateMachines` adds `FiniteStateMachineDispatcher`, the Part 16
transition guard used by DI software update and later by Robotics task
control.
**`Opc.Ua.Types`**
- Node copies no longer consume NodeIds from the `NodeIdFactory`.
`Initialize` materialises children through `CreateChild`, which assigns
a per-instance NodeId, but the copy then overwrites every child NodeId
from its source, so the assignment is discarded. A counting factory
silently burned identifiers; a tracking one leaked them.
- `JsonDecoder` resolves a relative encodeable type id against the
namespace table before the factory lookup.
**`Opc.Ua.Client`** — a file system path segment written without a
namespace prefix is qualified with the namespace of the parent it is
resolved against, matching the provider-owned BrowseNames.
**`Directory.Build.targets`** — the `RestrictForLegacyTfm` no-op now
also applies when a project pins a single `TargetFramework` and
`CustomTestTarget` names a different one. That is the same situation it
already handled for the legacy frameworks, and it is what keeps the
per-TFM CI matrix green once net10.0-only projects appear later in the
stack.
## Validation
`dotnet build UA.slnx` — 0 errors.
| Suite | Result |
| --- | --- |
| Opc.Ua.Types.Tests | 8088 / 0 |
| Opc.Ua.Server.Tests | 3873 / 1 |
| Opc.Ua.Client.Tests | 2105 / 0 |
| Opc.Ua.Core.Tests | 4145 / 0 |
| Opc.Ua.Features.Tests | 134 / 0 |
The single `Opc.Ua.Server.Tests` failure is
`ConfigureApplicationBuildsSharedClientAndServerConfigurationAsync`,
which is pre-existing and environmental: the PKI path in my working
directory exceeds MAX_PATH. It reproduces on clean `master` and passes
from a shorter directory.
---------
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 8cbb8cd0-f0cb-4ab0-bea2-6202fbf69485
romanett