# Description
Introduces a pluggable user-identity provider model covering all OPC UA
Part 6 §6.5 mechanisms (Anonymous, UserName, X509, IssuedToken/JWT) on
both client and server, with full
`Microsoft.Extensions.DependencyInjection` integration, plus the Part 12
§9 `AuthorizationService` two-phase token-request flow **including
refresh-token rotation**, the Part 12 §8 KeyCredential Push model, and a
clean provider model for OPC 10000-12 §7.2 `ApplicationSelfAdmin`. The
work is split across phase-by-phase commits so it can be reviewed
independently; nothing here changes wire-level behaviour or forces
existing applications to migrate.
### Documentation
All under `Docs/`:
- `IdentityProviders.md` — full developer guide: three-layer model,
recipes, configuration reference, "what gets auto-wired" matrix, JWS
algorithm table, identity-augmenters section, **"Implementing your own
provider"** how-to subsections for Entra / OIDC / Windows / AspNetCore
(sibling files merged in per review feedback).
- `DependencyInjection.md` — `Identity` sections with `appsettings.json`
examples, identity-extension matrix, `WithAuthorizationService` +
`WithKeyCredentialPush` + `AddIdentityAugmenter` extensions documented.
- `RoleBasedUserManagement.md` — claim-criteria callout describing
`IIdentityClaims` probe surface.
- `AuthorizationService.md` — Architecture diagram +
`IAccessTokenProvider` conceptual narrative restored from master; modern
`StartRequestToken` / `FinishRequestToken` flow leads; refresh-token
recipe added.
- `KeyCredentialService.md` — Push model + Pull vs Push vs Bridge
decision matrix + Hybrid (Push + Pull) section; explicit experimental
warning for the bridge.
- `GDS.md` — KeyCredential Push, `StartRequestToken`,
`GdsApplicationSelfAdminProvider`, **shipped Refresh-token support with
rotation policy and audit semantics** all documented.
- `MigrationGuide.md` — User Identity Providers section listing
`[Obsolete]` markers + mechanical recipes; SelfAdmin migration via
`IIdentityAugmenter`; `EnableRefreshTokens` default note.
- `README.md` index entries.
## 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.
- [x] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
Drive the solution to zero warnings / zero errors with analyzers on,
promote the consistently-fixed rules to error, and lock in coverage
on the only line of new logic.
Introduces a consistent `Microsoft.Extensions.DependencyInjection`
surface across the OPC UA libraries. Every consumer starts from a single
root entry point and chains feature-specific extension methods on a
unified builder. PubSub is intentionally excluded per the original
scope.
```csharp
services
.AddOpcUa() // Stack/Opc.Ua.Core
.AddServer(o => { /* … */ }) // Libraries/Opc.Ua.Server
.AddNodeManager<MyNodeManagerFactory>()
.Services
.AddOpcUa()
.AddClient(o => { /* … */ }); // Libraries/Opc.Ua.Client
```
Manual non-DI constructors (`new ApplicationInstance(...)`, `new
StandardServer(...)`, `new LdsServer(...)`, `new ManagedSession(...)`,
etc.) remain unchanged — DI is purely additive for users who want the
.NET Generic Host to own application lifetime, logging, and
configuration.
### What ships
| Feature library | Method on `IOpcUaBuilder` | Returns |
|----------------------------------------------|-------------------------------------------|--------------------------|
| `Opc.Ua.Core` (root) | `services.AddOpcUa()` | `IOpcUaBuilder` |
| `Opc.Ua.Configuration` | `builder.AddApplicationInstance()` |
`IOpcUaBuilder` |
| `Opc.Ua.Client` | `builder.AddClient(opt => …)` |
`IOpcUaClientBuilder` |
| `Opc.Ua.Client.ComplexTypes` | `builder.AddComplexTypes()` |
`IOpcUaBuilder` |
| `Opc.Ua.Server` | `builder.AddServer(opt => …)` |
`IOpcUaServerBuilder` |
| `Opc.Ua.Gds.Client.Common` | `builder.AddGdsClient(opt => …)` |
`IGdsClientBuilder` |
| `Opc.Ua.Gds.Server.Common` | `builder.AddGdsServer(opt => …)` |
`IGdsServerBuilder` |
| `Opc.Ua.Lds.Server` | `builder.AddLdsServer(opt => …)` |
`ILdsServerBuilder` |
| `Opc.Ua.WotCon.Server` | `builder.AddWotConServer(opt => …)` |
`IWotConServerBuilder` |
| `Opc.Ua.WotCon.Client` | `builder.AddWotConClient(opt => …)` |
`IOpcUaBuilder` |
### Design highlights
- **Binary-safe inheritance** — `IOpcUaBuilder :
IDependencyInjectionBuilder` so any existing `AddLogging(this
IDependencyInjectionBuilder)` callers keep compiling unchanged.
- **Three options overloads** per feature: `Action<TOptions>`
(AOT-safe), `IConfiguration`, `IConfigurationSection`. The two binding
overloads are annotated `[RequiresUnreferencedCode]` /
`[RequiresDynamicCode]`. Section names follow the `OpcUa:<Feature>`
convention (`OpcUa:Server`, `OpcUa:Client`, `OpcUa:Gds:Server`,
`OpcUa:Lds`, …).
- **Generic Host integration** — each server feature (regular, GDS, LDS)
registers its own `BackgroundService`. Marker singletons throw
`InvalidOperationException` on duplicate `.AddServer()` /
`.AddGdsServer()` / `.AddLdsServer()`. A regular server + GDS + LDS can
coexist in one host; each owns its own `IApplicationInstance` produced
by a shared `IApplicationInstanceFactory` so PKI roots, endpoints, and
certificates don't collide.
- **Registration isolation** — node managers registered under the
regular server via `.AddNodeManager<T>()` are wrapped in
`OpcUaServerNodeManagerRegistration` so they don't bleed into the GDS /
LDS hosted services.
- **WoT Connectivity server** composes on top of the regular server
feature: `.AddServer(...).AddWotConServer(...)` registers
`WotConnectivityNodeManagerFactory` as a server node-manager
registration.
- **Unified telemetry** — `services.AddOpcUa()` registers
`ITelemetryContext` via `TryAddSingleton` using a new
`ServiceProviderTelemetryContext` that resolves the host's
`ILoggerFactory` on first use. User-supplied registrations win.
### Removed pre-release DI surface
The pre-release `services.AddOpcUaServer(...)`,
`services.AddOpcUaClient(...)`, `services.AddOpcUaGdsClient(...)`
extensions are deleted. `IClientBuilder` was renamed to
`IOpcUaClientBuilder`. In-repo callers migrated:
- `Applications/MinimalCalcServer/Program.cs`
- `Applications/MinimalBoilerServer/Program.cs`
- `Tests/Opc.Ua.Client.Tests/ClientBuilder/OpcUaClientBuilderTests.cs`
(renamed from `OpcUaClientServiceCollectionExtensionsTests.cs`)
- Docs (`MigrationGuide.md`, `Sessions.md`,
`SourceGeneratedNodeManagers.md`, README, new
`Docs/DependencyInjection.md`)
### csproj audit
Pruned every redundant `Microsoft.Extensions.*` package reference.
`Opc.Ua.Core` already pulls in `Microsoft.Extensions.Diagnostics` and
`Microsoft.Extensions.Logging`, which transitively expose DI / Options /
Configuration.Abstractions / Options.ConfigurationExtensions to every
downstream library. Only `Microsoft.Extensions.Hosting.Abstractions`
stays explicit on the server libraries (it isn't transitively
available). Also pruned redundant `System.Formats.Asn1` (Bindings.Https)
and `System.Collections.Immutable` (Security.Certificates).
### Tests
50 new tests in eight projects:
| Project | Tests |
|--------------------------------------|-------|
| `Opc.Ua.Core.Tests` | 12 |
| `Opc.Ua.Client.Tests` | 4 |
| `Opc.Ua.Client.ComplexTypes.Tests` | 3 |
| `Opc.Ua.WotCon.Tests` | 6 |
| `Opc.Ua.Lds.Tests` | 5 |
| `Opc.Ua.Gds.Tests` | 6 |
| `Opc.Ua.Server.Tests` (integration) | 10 |
| `Opc.Ua.Aot.Tests` (smoke) | 4 |
| **Total** | **50** |
Combined-host integration tests cover the rubber-duck-driven scenarios:
telemetry-context override across legacy and new entry paths, server +
GDS + LDS coexistence with distinct ports and PKI roots,
duplicate-registration rejection, and node-manager isolation across
features.
### AOT
`dotnet publish Tests/Opc.Ua.Aot.Tests -c Release -r win-x64
--self-contained` reports zero `IL2026` / `IL3050` / `IL2104` warnings
from the new DI surface. All generic registrations carry
`[DynamicallyAccessedMembers(PublicConstructors)]`. AOT consumers stick
to the `Action<TOptions>` overload exclusively; the new
`Tests/Opc.Ua.Aot.Tests/HostingAotTests.cs` smoke fixture exercises this
end-to-end.
Concrete sub-types of the abstract OptionSet DataType (i=12755, e.g. AccessRights, CarExtras, OptionSetBase) were silently skipped by ComplexTypeSystem.LoadBaseStructureDataTypesAsync when only an EnumDefinition or OptionSetValues property was available. This change registers them with a new runtime class Opc.Ua.Encoders.OptionSet that reuses the generated Opc.Ua.OptionSet wire format (Value/ValidBits ByteStrings) and self-registers via IEncodeableType.
Key changes:
- New Stack/Opc.Ua/Types/OptionSet.cs with EnumDefinition-driven bit accessors (by name and index), GetSetFieldNames helper, and a fixed ByteLength derived from the highest declared bit per OPC UA Part 3 paragraph 8.40 / 3.2.8. SetBit throws ArgumentOutOfRangeException outside that range and always materializes Value/ValidBits to the fixed length.
- New AddOptionSetType entry point on IComplexTypeBuilder (source-breaking addition for custom implementations); DefaultComplexTypeBuilder implements it. The Reflection.Emit ComplexTypeBuilder throws NotSupportedException.
- ComplexTypeSystem detects OptionSet descendants via a HasSubtype walk and resolves the EnumDefinition from DataTypeDefinition or the OptionSetValues property fallback before the old skip path.
- Removed stale V1.04 OptionSet limitation remark from ComplexTypeSystem.
- 10 unit tests in Tests/Opc.Ua.Client.Tests/ComplexTypes/DefaultOptionSetTests.cs covering factory registration, bit accessors, binary round-trip via ExtensionObject, hand-crafted Part 6 wire format, Clone/CreateInstance semantics, and the ByteLength invariant.
- Live-verified against opc.tcp://DESKTOP-BGFJS91:48010 (UA C++ SDK demo): AccessRights/CarExtras/OptionSetBase now appear in the registered custom-type list; no skip-log entries; LoadAsync(throwOnError:true) returns true.
- Docs/ComplexTypes.md Known Limitations reworded; Docs/MigrationGuide.md gains an OptionSet DataType support subsection.
UInteger-backed OptionSet DataTypes remain intentionally opaque (carried as their unsigned integer in a Variant).
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* make most ptojects aot compatible
* Remove newtonsoft
* Migrate all projects from Mono.Options to System.CommandLine 2.0.5
* Fix array clone
* Replace serializers for storage using new attribute driven type geberator
* Add new AOT integration tests covering all functional areas
* Documentation updates
Generate stack and application code using source generators
Change built in types to readonly structs
Update localized text implementation to use JSON text serializer
Status code with symbolic names
Immutable node ids
No boxing for all built in types <= 8 bytes in Variant.
Split user identity token and token handling via token handler
Add migration guide for breaking changes
This pull request modernizes the OPC UA .NET codebase and tests, removes .NET Standard 2.0 support from certificate/security code, and updates test code to use C# 12 and .NET 8+ features for clarity and maintainability.
- Certificate and BouncyCastle interop files (e.g., CertificateBuilder.cs, X509Extensions.cs, X509SignatureFactory.cs) are refactored to drop NETSTANDARD2_0 support and use modern .NET APIs and conditional compilation.
- Test code across the codebase is updated to use default, strongly-typed Parse methods, collection expressions, and improved async/await patterns.
- Exception handling and assertions in tests are modernized, and test method naming is made consistent with Async suffixes.
- The project and build files are updated to clarify Roslynator analyzer usage and remove obsolete netstandard tags.
- General code and test cleanup includes improved null safety, type safety, and removal of deprecated or unused code.
This change adds a **new Opc.Ua.Types** nuget that contains core types that do not rely on generated code. Why the name? Because almost all code that was in the Types subfolder is part of it, and because we do not want to change the name of the Opc.Ua.Core nuget/assembly because code relies on it. Any other name like base or bootstrap felt out of place due to the current structure already defining the name "types". Key design is to depend on only a small set of libraries with limited transitive dependencies, that includes hashcode, logging.abstraction, and for non standard20 builds System.Text.Json (needed for localizedText mul parsing). Also, key is to support .netstd 2.0 to support source generators and to allow removal of EEC_SUPPORT defines by removing std2.0 from core and all libraries.
The changes are mostly restructuring, and thus small but contain some key changes:
- **Status code** struct now comes with a Symbol field, which is used to carry symbols in case the code is not generated. Currently (until generated) the status code struct must be manually created with a symbol or the ToSymbolicId extension must be called in the core project. Future will generate Status code constants just like NodeId that contain the symbol which also removes the reflection-based lookup. Several tests needed to be adjusted as they checked the status code symbol strings instead of the code.
- **Core identifiers** are copied as they were needed for code to compile, that includes attributes, a subset of status codes and node identifiers. These will never change so no need to generate them.
- The types folder now contains **encoders**, except for json which is still in core. Once the json encoder is ported to system.text.json it will also be included and Newtonsoft.Json dropped as dependency (-> #3329).
- Since types relies on **IOperationContext** and **ISystemContext**, and these export IUserIdentity which relies on crypto, these were split and extended in core with ISessionOperationContext and ISessionSystemContext, which mean changes to ServerSystemContext and introduction of SessionOperationContext and SessionSystemContext classes that extend OperationContext and SystemContext. Some runtime checks in the server are therefore needed to get at the session and auth info, however, those are anyway optional fields and are not on the critical paths, and thus a type check is in order (and was done in the past already, but against OperationContext class).
- **Manifest resources** are now split between Core (nodeset zip, some generated resoures) and Types (built in bsd/xsds). This needs to be revisited later if the bsd/xsd need to be regenerated during type generation. Note that the embedded resource names changed as a result. Since these are only used internally and do not constitute public API this feels reasonable vs duplication of resources in 2 assemblies.
- Reflection however now needs to load not just the built in **encodeables** from Opc.Ua.Types assembly, but also the generated encodeables from Opc.Ua.Core assembly. For this a new helper Utils method was added to get the Core assembly when linked against Opc.Ua.Core otherwise null.
- Whatever utils methods needed to be split out into the new Opc.Ua.Types assembly, they are now in **CoreUtils** static class in Opc.Ua.Types, and Utils.xxxx forwards to them to ensure minimal changes. Later we would want to obsolete them in favor of CoreUtils, although it might make sense to split them again into domain specific utilities, such as networking, files, etc
- Allow setting ReturnDiagnostics on the session factory to ensure the diagnostic settings are part of "Create" also. Set them to SymbolicIdAndText by default.
- Better logging in unit tests, now also logs to progress including exception traces, also prefixes SERVER and TEST on console to attach the logs to the server or client side.
- GDS client stability improvements to ensure client reliably reconnects between calls when connection is lost.
- Do not dispose the application certificate when it is updated from GDS client to avoid existing sessions to crash with CryptographicException. This needs more improvements later on because it is rather hacky today.
- Remove the certificate cache in CertificateFactory (as per discussion and agreement) which allowed re-enabling the older UserIdentity API
- Logging improvements here and there to analyze issues in unit tests better
- Replaced `IList<INode>` with `List<INode>` in
`ComplexTypeSystem.cs` and `BaseComplexType.cs` for
better type safety.
- Updated string comparison in `ReverseConnectManager.cs`
to `StringComparison.Ordinal` for improved performance.
- Added a method to `ISession.cs`, `Session.cs`, and
`SessionAsync.cs` to trigger reloading instance certificates.
- Minor fixes in error handling in `Subscription.cs` and using pattern matching for type checks in several locations to improve code readability.
- Made minor adjustments to comments and documentation
for clarity and improved code quality.
- Updated `Variant` handling in preparation for immutable struct.
- Changed return types in `BaseObjectState.cs` and `BaseVariableTypeState.cs` to use `ObjectTypeIds` for iperf
- Cleaned up `ExpandedNodeId`
- Enhanced memory management error handling and readabilityand error handling in encoders
* Enhance enum definition handling and validation
Added a `string enumTypeName` parameter to the `ToEnumDefinition` methods in `ComplexTypeSystem.cs` and `DataTypeDefinitionExtension.cs` to improve enum field name generation, especially when original names are null or empty. Implemented a fallback mechanism to ensure robust naming.
In `ComplexTypeBuilder.cs`, added null checks for `typeName` to prevent runtime errors and ensure valid type definitions. Updated logic for defining enum literals to handle empty field names, ensuring unique names are generated based on `typeName` and enum value.
* Update Libraries/Opc.Ua.Client.ComplexTypes/TypeBuilder/ComplexTypeBuilder.cs
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Update Libraries/Opc.Ua.Client.ComplexTypes/DataTypeDefinitionExtension.cs
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Fix issue from code review
---------
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Add missing constants for JSON encoding.
* Update generated files to 1.05.04.
* Update NuGets
* Fix compile errors due to abstract types.
* Update nodesets.
* Update JSON Encoder/Decoder.
* Update with JSON encoder.
* Change prefix char.
* Change prefix to uppercase.
* Fix JsonEncoder
* Fix null pointer.
* Update encoders to suppress artifacts.
* JSON encoding fixes.
* Fix JSON RawEncoding
* Update JSON encoders.
* Revert changes for Matrix in Variant.
* Update NodeSet.
* Resolve name conflict with new Opc.Ua types.
* Fix failing Tests
* Fix unit tests after change to Verbose/Compact encoding.
* Add final 1.05.04 generated classes and unit test fixes.
* Fix more unit tests.
* Update NodeSet to released version.
* Remove unintended changes to UANodeSet.xsd
* Update Schema/UANodeSet.xsd
* Merge breaking changes to JsonEncoder.cs from develop/main374
* Allow JObject in ExtensionObjects.
* fix version json
* Update generated files to UA-1.05.04-2025-01-08
* Some cleanup of the new APIs and Union implementation. (#2927)
* Some cleanup of the new APIs and Union implementation.
* fix build
* Handle status code Uncertain according to the specification (#2898)
* #2896: Write output arguments for good and uncertain status code
When a method state's call method is invoked the output arguments should be written in case the status code is good or uncertain. This behavior would be conform with the current specification.
* #2896: The service result corresponds the method call result
The result of the Call method in the CustomNodeManager2 class represents the status of the CallMethodResult. It does not correspond to the ServiceResult of the CallResponse, thus returning Good as a general response is incorrect behavior.
* Add SetHiResClockDisabled & fix Rejected Store Creation in ApplicationConfigurationBuilder (#2909)
Add the method SetHiResClockDisabled to IApplicationConfigurationBuilder
Fix the type of RejectedStore Created by the Builder to: CertificateStoreIdentifier
* revert based on feedback
* move some logic from class code to encoder/decoder
* Fix race condition on Nuget build (#2930)
- nodeset xmlzip is created in obj folders if multiple targets are built in parallel
* update common comments
* Update NodeSet files.
* Fix ReadSwitchField Implementation.
* Make UserIdentity.DisplayName writeable.
* Fix merge failures.
* Fix XmlElement encoding and bad NamespaceIndex fallback logic.
* Fix 2D array raw encoding.
* Add support for DesignToolOnly.
---------
Co-authored-by: Randy Armstrong <randy@sparhawksoftware.com>
Co-authored-by: Martin Regen <mregen@microsoft.com>
Co-authored-by: Martin Regen <7962757+mregen@users.noreply.github.com>
- Reduce memory allocations in JSON encoder by using stackalloc/ArrayPool
- Fix some new warnings in .NET9 code analyzers
- Fix fuzzing error in JsonDecoder
- do not use .NET9 libraries with .NET8 LTS builds #2931, #2940
- Bump langversion to 9 (max VS2019)
- Use official ASP.Net 2.3. libraries for .NET Framework (rel. Jan 15th)
- Port support for ECC NIST/Brainpool profiles from prototyping_ecc branch
- Implement CertProvider to load certs per connection / profile
- Backward compatibility of configuration for existing apps
- SecurityConfiguration specifies app cert types for each profile
- Autodetect the ECC support for brainpool/nist based on platform (mac OS 10 doesn't support brainpool)
- ECC supported on net48 / net5.0 / net 6.0 / netstandard2.1
- ECC supported on windows / linux / macOS (brainpool not < macOS11)
- Self signed certs for each profile are created on start similar to RSA
- RSA only profiles are supported on .NET standard 2.0
Co-authored-by: Martin Regen <mregen@microsoft.com>
- A CRL without revokedcertificates and other extensions caused a decoding error
- Add tests to permutate decode without revokedcertificates and extensions
- Fix: Add check for additional data after NextDateTime, skip otherwise
Fix warnings regarding localization, CLS compliance, performance. No functional changes.
Many but not all adressed:
CA1859
CA1868
CA1305
CA1310
CA1861
- based on the discussion, use IFormatProvider where appropriate in ToString
- bug: if the nested complex type is derived from an abstract type like a Union, the decoder uses the abstract type instead of the actual type to decode
- fix: the loop to determine the supertype of the type to be decoded stops too early and returns an invalid type reference, e.g. for Unions. Instead the loop will now continue until a valid BuiltInType or a Structure or Enumeration type is found.
- ICloneable was removed from generated code for the first port to .NET Standard 1.x, instead MemberwiseClone was used
- Reenable ICloneable for generated code
- Add ICloneable to built in types
- Fix code where MemberwiseClone is called instead of Clone
Fixes an issue found with a server with an address model that implements structures with abstract complex types and with structures which allow subtypes. The client could hang endless when building the complex type system in this case.
The StructureFieldAttribute has the wrong AttributeTypeIds set.
The changes add an API to ComplexTypeSystem to retrieve data type definitions that were created during type building to leverage them to build DataSetMetaDataType for OPC UA PubSub.
The changes include the following:
* Combine all conversion of enumerations into EnumDefinition and use the resulting to build the type
* Remove all other API from the type builder interface and implementation.
> The assumption is that these interfaces are used internally and removal will not cause a breaking change.
* Combine everything previously covered elsewhere into existing AddEnumType function.
* Add a NodeIdDictionary cache and fill that cache during load, as well as API to retrieve the data type definitions
* A complex type which has a property with datatype Number, UInteger or Integer causes an exception on encoding/decoding because the BuiltInType which is used in the BaseComplexType is BuiltInType.Null instead of BuiltInType.Variant.
* BaseComplexType may not handle enumerations as property correctly on encoding/decoding and may cause an exception.
Expose an 'ISession' interface as abstraction to ease unit testing.
Breaking changes are kept to minimal impact, but some changes maybe required to use ISession objects instead of Session.
Note: ISessionClientMethods is hand created, not yet by ModelCompiler
Improvements for complex types.
- Support to encode/decode complex type structures with multidimensional arrays.
- Perf improvements for type loader using new NodeCache fetch multiple interfaces.
- DataTypeDictionary validation when dependencies are used.
- interface for complex type resolver, to build custom types in code.
- improvements of console client to demonstrate browse/read of custom values
+++ Breaking changes +++
IDecoder interface change of the `ReadArray` method
- Return type is now `Array` for all types of arrays. Previously the method returned an array for 1-dim and a `Matrix` type for multidimensional arrays. In addition the convention in generated code is to use `Collection` for all 1-dim arrays, and so was built the `BaseComplexType`. The new convention is to expose the native `Array` type from a complex type, in all cases, hence the return type of `ReadArray` was changed to reflect that for a consistent programming model.
- `ReadArray` has a new parameter `systemType` to efficiently read encodeable types. Previously the `Type` of an encodeable was determined by the encodingid and lookup in the type factory, even when the Type is already known by the caller. The 'old' style is still supported.
- `ReadArray` supports to read encodeable type arrays which are directly encoded in structures. These arrays differ from standard encoding of arrays and they are handled when `BuiltInType.Null` is used as parameter.
Marc Schier