Files
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
..

OPC 40223 Pumps samples

Two console applications that show the Opc.Ua.Pumps* libraries end to end: a server that publishes pumps with the fluent builders, and a client that discovers and reads them with PumpsClient.

Sample What it does
PumpsServer Serves a duty/standby pair of cooling-water pumps and simulates them once a second
PumpsClient Discovers every pump, prints the whole pump, then streams live values and supervision changes

The Pumps developer guide explains every API used here.

Run

In two terminals:

dotnet run --project samples/Pumps/PumpsServer -- --port 62547
dotnet run --project samples/Pumps/PumpsClient -- --insecure --seconds 30

--insecure makes the client accept the server's self-signed certificate; never use it in production. The client also takes --url <endpoint> (default opc.tcp://localhost:62547/PumpsServer) and --seconds <n> (how long to stream, 0 to skip).

The client prints something like:

Pump CoolingPump_A  (ns=1;i=3788608060)
  Acme Pumps CW-80, serial CW80-0042, built 2024/3 in DE
  location: Plant 1 / Cooling skid
  Design:
    ClockwiseRotation                  True
    MaximumAllowableContinuousSpeed    3000 1/min
    MaximumAllowableWorkingPressure    1.6E+06 Pa
  Implementation:
    PumpBestEfficiency                 78 %
    RatedFlow                          25 kg/s
    RatedSpeed                         2900 1/min
  SystemRequirements:
    Fluid                              Cooling water
    MaximumFlow                        32 kg/s
    MinimumFlow                        6 kg/s
  Measurements:
    BearingTemperature                 27.92 °C
    DifferentialPressure               367831 Pa  [0 … 1600000]
    MassFlow                           21.58 kg/s  [0 … 32]
    NumberOfStarts                     0
    PumpEfficiency                     75.08 %  [0 … 100]
    PumpPowerInput                     9.64 kW
    Speed                              2821.17 1/min  [0 … 3000]
  Measurements/DriveEndBearing:
    OverallVibrationVelocityRMS        2.88 mm/s  [0 … 11.2]
    ReferenceStandardForVibrationMeasurement ISO 10816-3
  Signals:
    PumpOperation                      True
    StandBy                            False
  MultiPump: role Master, mode RedundancyOperation, 1 of 2 pumps in operation
  supervision: no active signals
  maintenance: OperatingState, Level1, failure False, operating time 12480 h
  port Suction: InletConnection, direction In, DN100 PN16 flange
  port Discharge: OutletConnection, direction Out, DN80 PN16 flange
  port Motor: Drive, direction -, no category
  Motor/Measurements:
    MotorCurrent                       18.84 A
    MotorTemperature                   35.92 °C
  document OperationManualLink: https://pumps.example.com/manuals/cw-80.pdf
  document TechnicalDataLink: https://pumps.example.com/datasheets/cw-80.pdf

Pump CoolingPump_B  (ns=1;i=1919434908)
  …

Polled 7 measurements with PumpReadOptions.ValuesOnly; MassFlow = 21.58

Watching 8 values for 45s (the pumps swap duty every 90 s; cavitation appears once a minute) …
  00:04:19  CoolingPump_A DriveEndBearing vRMS 2.91
  00:04:19  CoolingPump_A Cavitation       False
  00:04:19  CoolingPump_B PumpOperation    False
  00:04:19  CoolingPump_B Cavitation       False
  00:04:19  CoolingPump_A MassFlow         21.75
  00:04:19  CoolingPump_B MassFlow         0
  …
  00:04:56  CoolingPump_A DriveEndBearing vRMS 7.1
  00:04:56  CoolingPump_A Cavitation       True
  00:05:02  CoolingPump_A Cavitation       False

NodeIds and namespace indices are whatever the server assigned; only the browse names are stable.

What the server shows

File Shows
Program.cs AddPumps() and ConfigurePumps(...) on the generic host
PumpFleet.cs CreatePumpAsync, WithNameplate, every group builder (Design, Implementation, SystemRequirements, Measurements, Signals, Supervision(...), MultiPump, MaintenanceCategory(...), AddPort, Documentation), engineering units and ranges
PumpFleet.cs A vibration measurement from the <Vibration> placeholder with AddVibration, and the PumpUnit holder of the builders the simulation writes through
PumpSimulation.cs A BackgroundService driving values, a duty/standby exchange every 90 s, and a cavitation episode once a minute
PumpDatasheet.cs Static pump data and UNECE engineering units built per OPC 10000-8 §5.6.3

Runtime updates. The simulation writes through the builders it kept at configuration time. Every Set/SetAnalog/SetDiscrete publishes the change, so subscribed clients see each update without further code.

What the client shows

Code in Program.cs Shows
connection.Session.Pumps(telemetry) Creating the client; registers the OPC 40223 structured types
pumps.IsSupported Detecting whether the server publishes OPC 40223
EnumeratePumpsAsync Discovery from the DI DeviceSet and the Machinery Machines folder
ReadPumpAsync → PumpSnapshot The whole pump in one pass; each group has its own Read…Async too
PumpValueSet / PumpValue Values with engineering unit and range, AsDouble, AsString
PumpValueSet.Groups Nested groups such as the DriveEndBearing vibration measurement
PumpSupervisionStatus.ActiveSignals Only the raised supervision signals
PumpMaintenanceData StateOfTheItem, MaintenanceLevel, HasFailure
ReadMeasurementsAsync(…, PumpReadOptions.ValuesOnly, …) Cheap polling once the metadata is known
Streaming.SubscribeDataChangesAsync(value.NodeId, …) Subscribing to a reading; PumpValue.NodeId is the node that carries it, also for discrete signals

SampleSession.cs is the session setup. It keeps the ApplicationInstance alive until the session closes, because the instance owns the CertificateManager the session validates with.

Publish as NativeAOT

Both samples are NativeAOT-compatible on net10.0:

dotnet publish samples/Pumps/PumpsServer -c Release -f net10.0 -r osx-arm64

Troubleshooting

Symptom Fix
Client reports BadCertificateUntrusted Pass --insecure for the demo, or trust the server certificate in the client's PKI (under the local application data folder, OPC Foundation/PumpsClient/pki)
The server publishes no pumps. Wait for the server log line Materialised pump … before starting the client
Port already in use Start the server with --port <n> and the client with --url opc.tcp://localhost:<n>/PumpsServer