Merge remote-tracking branch 'origin/master' into copilot/publisher3-upstream-parity-session-cleanup

# Conflicts:
#	Libraries/Opc.Ua.Client/Session/ManagedSession.cs
#	Tests/Opc.Ua.Server.Tests/QuickstartsServerUtilitiesTests.cs

Author: marcschier

.editorconfig

@@ -481,8 +481,11 @@ dotnet_diagnostic.CA1724.severity                                             =
 
 # CA1848: Use the LoggerMessage delegates
 dotnet_diagnostic.CA1848.severity = none
-# CA1873: Avoid potentially expensive logging
-dotnet_diagnostic.CA1873.severity = none
+# CA1873: Avoid potentially expensive logging. Enabled solution-wide (issue
+# #3908) now that the entire code base uses source-generated [LoggerMessage]
+# logging; any regression back to direct ILogger.Log* calls with expensive
+# arguments is flagged.
+dotnet_diagnostic.CA1873.severity = warning
 # CA1000: Do not declare static members on generic types
 dotnet_diagnostic.CA1000.severity = none
 # CA1031: Do not catch general exception types

.github/copilot-instructions.md

@@ -20,6 +20,7 @@ This is the official OPC UA .NET Standard Stack from the OPC Foundation. It prov
 - **Build**: Use Visual Studio 2026 or `dotnet build`
 - **Key solutions**:
   - `UA.slnx` - Contains all projects
+- **Contributor guide**: see [`Docs/DeveloperGuide.md`](../Docs/DeveloperGuide.md) for prerequisites, building (including per-TFM), testing, coding standards, and how-to recipes.
 
 ### Project Structure
 - `Libraries/` - Core OPC UA libraries (Client, Server, Configuration, etc.)
@@ -76,7 +77,7 @@ This is the official OPC UA .NET Standard Stack from the OPC Foundation. It prov
   - All source generated code, in particular ObjectType proxies should be used over manually calling service calls inside new clients.
   - Consider using the source generators to implement emitting "boilerplate", especially if it is related to the OPC UA standard (e.g. information model).
   - Base services: File System, Certificate manager, Secret store, State machine, Alarms and conditions Streaming subscription, Sessions, etc. in new code. (Documented in docs/*).
-  - Observability is plumbed through via `ITelemetryContext`. Use it to create a `ILogger` for logging.
+  - Observability is plumbed through via `ITelemetryContext`. Use it to create an `ILogger` for logging; follow the source-generated logging conventions in [`Docs/DeveloperGuide.md`](../Docs/DeveloperGuide.md#add-a-log-message-source-generated).
 - If reuse is not possible, ASK whether to extend an existing feature so it becomes reuseable.
 
 ### Code Style
@@ -102,6 +103,7 @@ This is the official OPC UA .NET Standard Stack from the OPC Foundation. It prov
 - Assembly prefix: `Opc.Ua` (Except applications, or if otherwise requested)
 - Package prefix: `OPCFoundation.NetStandard`
 - Always use a line break after `<summary>` and before `</summary>` for all members (except for documentation of fields). This applies to **every** XML-doc summary, including in sample/application code — never write a single-line `/// <summary> ... </summary>`; always put the text on its own line between the opening and closing tags.
+- Use source-generated `[LoggerMessage]` logging; never call `ILogger.LogInformation/LogError/...` directly. Follow the per-file `<Class>Log` and per-assembly `<AssemblyToken>EventIds` conventions in [`Docs/DeveloperGuide.md`](../Docs/DeveloperGuide.md#add-a-log-message-source-generated).
 
 ### Security Requirements
 - **Never hardcode credentials, certificates, or secrets** in source code
@@ -139,6 +141,7 @@ This is the official OPC UA .NET Standard Stack from the OPC Foundation. It prov
 - Update `/README.md` for significant changes
 - Keep `NugetREADME.md` updated for package-related changes
 - Document breaking changes prominently
+- Keep [`Docs/DeveloperGuide.md`](../Docs/DeveloperGuide.md) (the contributor onboarding guide) current when build, test, or coding-convention changes affect contributors.
 
 #### Documentation Style
 - Use clear, technical language

.github/workflows/preview-publish.yml

@@ -89,7 +89,7 @@ jobs:
           dotnet tool install --version 3.0.45 --tool-path "$env:TOOLS_DIR" NuGetKeyVaultSignTool
 
       - name: Setup NuGet
-        uses: NuGet/setup-nuget@v2
+        uses: NuGet/setup-nuget@v4
         with:
           nuget-version: '>=7.0.0'
 

Applications/ConsoleLdsServer/EventIds.cs

@@ -0,0 +1,45 @@
+/* ========================================================================
+ * Copyright (c) 2005-2026 The OPC Foundation, Inc. All rights reserved.
+ *
+ * OPC Foundation MIT License 1.00
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The complete license agreement can be found here:
+ * http://opcfoundation.org/License/MIT/1.00/
+ * ======================================================================*/
+
+namespace Opc.Ua.Lds.Server.Console
+{
+    /// <summary>
+    /// Centrally managed event id offsets for source-generated log messages in this assembly.
+    /// </summary>
+    /// <remarks>
+    /// Each per-file <c>&lt;ClassName&gt;Log</c> class allocates its event ids relative to the
+    /// offset constant below, using <c>offset + &lt;zero-based message index&gt;</c>. Every block
+    /// reserves at least five spare slots for future messages and is rounded up to the next
+    /// multiple of ten so that ids can be documented and managed from this single location.
+    /// </remarks>
+    internal static class ConsoleLdsServerEventIds
+    {
+        public const int Program = 0;
+    }
+}

Applications/ConsoleLdsServer/Program.cs

@@ -181,7 +181,7 @@ await application
                 }
                 catch (Exception ex)
                 {
-                    logger?.LogError(ex, "Fatal error starting LDS.");
+                    logger?.FatalErrorStartingLds(ex);
                     System.Console.Error.WriteLine(ex);
                     return 2;
                 }
@@ -194,4 +194,12 @@ await application
             return rootCommand.Parse(args).InvokeAsync();
         }
     }
+
+    internal static partial class ProgramLog
+    {
+        [LoggerMessage(EventId = ConsoleLdsServerEventIds.Program + 0, Level = LogLevel.Error,
+            Message = "Fatal error starting LDS.")]
+        public static partial void FatalErrorStartingLds(
+    this Microsoft.Extensions.Logging.ILogger logger, Exception exception);
+    }
 }

Applications/ConsoleReferenceClient/AlarmClientSample.cs

@@ -35,6 +35,7 @@
 using Opc.Ua.Client;
 using Opc.Ua.Client.Alarms;
 using Opc.Ua.Client.Subscriptions.Streaming;
+using Quickstarts.ConsoleReferenceClient;
 
 namespace Quickstarts
 {
@@ -141,7 +142,7 @@ await alarms.AcknowledgeAsync(
                     }
                     catch (Exception ex)
                     {
-                        m_logger.LogError(ex, "Acknowledge failed");
+                        m_logger.AcknowledgeFailed(ex);
                     }
                 }
             }
@@ -195,4 +196,12 @@ private static void PrintAlarm(ConditionTypeRecord record)
             }
         }
     }
+
+    internal static partial class AlarmClientSampleLog
+    {
+        [LoggerMessage(EventId = ConsoleReferenceClientEventIds.AlarmClientSample + 0, Level = LogLevel.Error,
+            Message = "Acknowledge failed")]
+        public static partial void AcknowledgeFailed(this ILogger logger, Exception ex);
+    }
+
 }