# Description
`ConditionState.m_branches` (a plain `Dictionary`) was read and written
from multiple threads without synchronization. A state change on a
background thread could mutate the dictionary while readers
(`GetRetainState`/`UpdateRetainState`, `ConditionRefresh`, `GetBranch`)
enumerated it, yielding torn entries and native access violations
(observed as `IsBranch` on a null `this`). This ports the master378 fix
to `master`, where the type lives at
`Stack/Opc.Ua.Core.Types/State/ConditionState.cs` and uses
`ByteString`/nullable refs.
- **Lock all branch access**: added a private `m_branchesLock` guarding
every read/write of `m_branches` (`CreateBranch`, `GetBranch`,
`ReplaceBranchEvent`, `RemoveBranchEvent`, `ClearBranches`,
`GetBranchCount`).
- **Snapshot enumeration**: `GetBranches()` now returns a copy taken
under the lock, so internal readers and
`AlarmHolder.GetBranchesForConditionRefresh` iterate a stable collection
while other threads mutate the live one. Public signature is unchanged.
- **Test**: added `ConcurrentBranchAccessIsThreadSafe`, stressing
concurrent create/clear writers against enumerate/count readers.
`lock` is used rather than `SemaphoreSlim` because all affected methods
are synchronous. Each `ConditionState` holds its own lock, so the
recursive `UpdateRetainState` traversal across branches neither contends
nor deadlocks. `ConcurrentDictionary` was rejected: it would change the
public return type and still leave compound read-modify-write sequences
(e.g. `ReplaceBranchEvent`) unprotected.
## Related Issues
## 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.
- [ ] 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: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Suciu Mircea Adrian <Mircea-Adrian.Suciu@softing.com>
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.
* Add per-namespace NodeSet2 export and CLI option
Implemented ExportNodesToNodeSet2PerNamespaceAsync in ClientSamples to export nodes into separate NodeSet2 XML files per namespace, excluding OPC Foundation companion specs. Added a helper for safe filename generation. Introduced a new -e/--export command-line option in Program.cs to trigger this export after node fetching. Also added System.Xml.Linq import for potential XML handling.
* Add NodeSetExportOptions for flexible NodeSet2 export
Introduce NodeSetExportOptions to control which attributes and values are exported to NodeSet2 XML, with Default, Minimal, and Complete presets. Overload ExportNodesToNodeSet2 to accept these options and update internal logic accordingly. Update CreateNodeState to honor export preferences. Add comprehensive unit tests for all export modes and ensure backward compatibility. Update ClientSamples to use Complete export mode.
* Refactor NodeSet export options for minimal default output
- Change ExportValues default to false; values only for Complete option
- Remove ExportUserAccessLevel and ExportMethodDeclarationId options
- Always export MethodDeclarationId; export UserAccessLevel only if different from AccessLevel
- Remove Minimal option; Default now produces minimal schema output
- Update export logic and tests to reflect new option semantics
- Rename and revise unit test to verify new default and complete behaviors
* Remove unused BitVector32 import
* Add ExportUserContext option to NodeSet2 export
Introduce ExportUserContext to NodeSetExportOptions, allowing selective export of user context attributes (UserAccessLevel, UserExecutable, UserWriteMask, UserRolePermissions) in NodeSet2 files. Update export logic to honor this option and add unit tests to verify correct behavior. This enhances flexibility and control over exported user-specific metadata.
---------
Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
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