fix(repo): restore multi-TFM compatibility for Release pack

adapter/MTConnect.NET-Applications-Adapter/Service.cs

@@ -3,7 +3,9 @@
 
 using MTConnect.Services;
 using NLog;
+#if NET5_0_OR_GREATER
 using System.Runtime.Versioning;
+#endif
 
 namespace MTConnect.Applications
 {

agent/MTConnect.NET-Applications-Agents/Service.cs

@@ -3,7 +3,9 @@
 
 using MTConnect.Services;
 using NLog;
+#if NET5_0_OR_GREATER
 using System.Runtime.Versioning;
+#endif
 
 namespace MTConnect.Applications
 {

libraries/MTConnect.NET-Services/MTConnectAdapterService.cs

@@ -5,7 +5,9 @@
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
+#if NET5_0_OR_GREATER
 using System.Runtime.Versioning;
+#endif
 using System.ServiceProcess;
 
 namespace MTConnect.Services

libraries/MTConnect.NET-Services/MTConnectAgentService.cs

@@ -5,7 +5,9 @@
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
+#if NET5_0_OR_GREATER
 using System.Runtime.Versioning;
+#endif
 using System.ServiceProcess;
 
 namespace MTConnect.Services

libraries/MTConnect.NET-Services/WindowsService.cs

@@ -3,7 +3,9 @@
 
 using System.Linq;
 using System.Runtime.InteropServices;
+#if NET5_0_OR_GREATER
 using System.Runtime.Versioning;
+#endif
 using System.Security.Principal;
 using System.ServiceProcess;
 

tests/MTConnect.NET-Common-Tests/MTConnect.NET-Common-Tests.csproj

@@ -22,7 +22,10 @@
       (tests/MTConnect.NET-Common-Tests/Http/), which reflection-inspect
       MTConnectPostResponseHandler.ReadRequestBytes and drive the Ceen
       LimitedBodyStream drain path to pin the CA2022 short-read handling
-      contract across every TFM.
+      contract across every TFM. It is also referenced from
+      SupportedOSPlatformAttributePresenceTests
+      (tests/MTConnect.NET-Common-Tests/Platform/) to reflection-assert the
+      [SupportedOSPlatform("windows")] attribute on the HTTP server surface.
     -->
     <ProjectReference Include="..\..\libraries\MTConnect.NET-HTTP\MTConnect.NET-HTTP.csproj" />
     <!--
@@ -33,6 +36,19 @@
       equivalence under net9.0.
     -->
     <ProjectReference Include="..\..\libraries\MTConnect.NET-TLS\MTConnect.NET-TLS.csproj" />
+    <!--
+      Project references added for SupportedOSPlatformAttributePresenceTests
+      (tests/MTConnect.NET-Common-Tests/Platform/). The fixture loads each
+      assembly that owns one of the six Windows-only Service / HTTP-server
+      types decorated by commit dd2eb424 (2026-05-22) and reflection-asserts
+      the [SupportedOSPlatform("windows")] attribute is still present. The
+      references are deliberately reflection-only — no test instantiates
+      WindowsService or starts an HTTP server, so the heavier transitive
+      surface is fine to drag in.
+    -->
+    <ProjectReference Include="..\..\libraries\MTConnect.NET-Services\MTConnect.NET-Services.csproj" />
+    <ProjectReference Include="..\..\agent\MTConnect.NET-Applications-Agents\MTConnect.NET-Applications-Agents.csproj" />
+    <ProjectReference Include="..\..\adapter\MTConnect.NET-Applications-Adapter\MTConnect.NET-Applications-Adapter.csproj" />
   </ItemGroup>
 
 </Project>

tests/MTConnect.NET-Common-Tests/Platform/SupportedOSPlatformAttributePresenceTests.cs

@@ -0,0 +1,156 @@
+// Copyright (c) 2026 TrakHound Inc., All Rights Reserved.
+// TrakHound Inc. licenses this file to you under the MIT license.
+
+using System;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.Versioning;
+using NUnit.Framework;
+
+namespace MTConnect.NET_Common_Tests.Platform
+{
+    // Pins the [SupportedOSPlatform("windows")] decoration on every type or
+    // method that was annotated by commit dd2eb424 (2026-05-22) to silence
+    // the CA1416 platform-compatibility analyzer on .NET 8. The attribute
+    // type ships in System.Runtime on .NET 5.0+ but is absent from net4x
+    // and netstandard2.0; PR #218 wraps each declaration plus its
+    // using-directive in `#if NET5_0_OR_GREATER ... #endif` so the
+    // Release pack survives the full TFM matrix.
+    //
+    // This fixture only exercises the net8.0 build path (the only TFM
+    // every test project targets), and so cannot directly fail under the
+    // pre-fix code (net8.0 keeps the attribute regardless of the wrap).
+    // Its value is REGRESSION-PREVENTIVE: a future contributor who
+    // removes the attribute outright — or who narrows the wrap to a
+    // condition that excludes net8.0 — fails this test, and the
+    // protection the original commit added stays in place.
+    /// <summary>Pins SupportedOSPlatform("windows") on every site PR #218 wraps.</summary>
+    [TestFixture]
+    [Category("MultiTfmCompat")]
+    public class SupportedOSPlatformAttributePresenceTests
+    {
+        private static void AssertWindowsPlatform(MemberInfo member, string description)
+        {
+            var attributes = member
+                .GetCustomAttributes(typeof(SupportedOSPlatformAttribute), inherit: false)
+                .Cast<SupportedOSPlatformAttribute>()
+                .ToArray();
+
+            Assert.That(attributes, Is.Not.Empty,
+                $"{description}: expected [SupportedOSPlatform] attribute.");
+            Assert.That(
+                attributes.Any(a => string.Equals(a.PlatformName, "windows", StringComparison.Ordinal)),
+                Is.True,
+                $"{description}: expected PlatformName == \"windows\" but got " +
+                $"[{string.Join(", ", attributes.Select(a => a.PlatformName))}].");
+        }
+
+        /// <summary>MTConnect.Services.WindowsService carries the Windows-only attribute.</summary>
+        [Test]
+        public void WindowsService_carries_supported_os_platform_windows()
+        {
+            // WindowsService is internal — reach it via Assembly.GetType
+            // rather than typeof(...).
+            var servicesAssembly = typeof(MTConnect.Services.MTConnectAgentService).Assembly;
+            var windowsServiceType = servicesAssembly.GetType(
+                "MTConnect.Services.WindowsService", throwOnError: true);
+            AssertWindowsPlatform(windowsServiceType!,
+                "MTConnect.Services.WindowsService");
+        }
+
+        /// <summary>MTConnect.Services.MTConnectAgentService carries the Windows-only attribute.</summary>
+        [Test]
+        public void MTConnectAgentService_carries_supported_os_platform_windows()
+        {
+            AssertWindowsPlatform(typeof(MTConnect.Services.MTConnectAgentService),
+                "MTConnect.Services.MTConnectAgentService");
+        }
+
+        /// <summary>MTConnect.Services.MTConnectAdapterService carries the Windows-only attribute.</summary>
+        [Test]
+        public void MTConnectAdapterService_carries_supported_os_platform_windows()
+        {
+            AssertWindowsPlatform(typeof(MTConnect.Services.MTConnectAdapterService),
+                "MTConnect.Services.MTConnectAdapterService");
+        }
+
+        /// <summary>The agent-application Service class carries the Windows-only attribute.</summary>
+        [Test]
+        public void AgentApplications_Service_carries_supported_os_platform_windows()
+        {
+            // Both agent-application and adapter-application Service
+            // types live under the same MTConnect.Applications
+            // namespace; distinguish by assembly.
+            var agentServiceType = typeof(MTConnect.Applications.IMTConnectAgentApplication).Assembly
+                .GetType("MTConnect.Applications.Service", throwOnError: true);
+            AssertWindowsPlatform(agentServiceType!,
+                "MTConnect.Applications.Service (agent application)");
+        }
+
+        /// <summary>The adapter-application Service class carries the Windows-only attribute.</summary>
+        [Test]
+        public void AdapterApplications_Service_carries_supported_os_platform_windows()
+        {
+            var adapterServiceType = typeof(MTConnect.Applications.IMTConnectAdapterApplication).Assembly
+                .GetType("MTConnect.Applications.Service", throwOnError: true);
+            AssertWindowsPlatform(adapterServiceType!,
+                "MTConnect.Applications.Service (adapter application)");
+        }
+
+        /// <summary>The Ceen HTTP-server socket-handle sites carry the Windows-only attribute.</summary>
+        [Test]
+        public void CeenHttpServer_socket_handle_sites_carry_supported_os_platform_windows()
+        {
+            // Both annotated members are internal to MTConnect.NET-HTTP:
+            //   * Ceen.Httpd.HttpServer.InterProcessBridge.HandleRequest
+            //   * Ceen.Httpd.HttpServer.RunClient (private static)
+            // Reach them via Assembly.GetType + reflection.
+            var httpAssembly = typeof(MTConnect.Servers.Http.MTConnectHttpRequests).Assembly;
+            var httpServerType = httpAssembly.GetType(
+                "Ceen.Httpd.HttpServer", throwOnError: true)!;
+            var socketInformationType = typeof(System.Net.Sockets.SocketInformation);
+
+            // The [SupportedOSPlatform("windows")] attribute lives on
+            // Ceen.Httpd.HttpServer.AppDomainBridge.HandleRequest(
+            // SocketInformation, EndPoint, string) — AppDomainBridge,
+            // not InterProcessBridge, is the AppDomain-marshallable
+            // sibling that wraps the duplicated socket handle. The
+            // RunClient(SocketInformation,...) private static method on
+            // HttpServer itself is the second site.
+            var bridgeType = httpServerType.GetNestedType(
+                "AppDomainBridge", BindingFlags.Public | BindingFlags.NonPublic);
+            Assert.That(bridgeType, Is.Not.Null,
+                "Ceen.Httpd.HttpServer.AppDomainBridge nested type not found.");
+
+            const BindingFlags allInstance = BindingFlags.Public | BindingFlags.NonPublic
+                | BindingFlags.Instance;
+            // HandleRequest has two overloads; the SocketInformation-typed
+            // one is the Windows-only path the attribute decorates. The
+            // Socket-typed overload is cross-platform.
+            var handleRequestCandidates = bridgeType!.GetMethods(allInstance)
+                .Where(m => m.Name == "HandleRequest")
+                .ToArray();
+            var handleRequest = handleRequestCandidates
+                .FirstOrDefault(m => m.GetParameters().Length > 0
+                    && m.GetParameters()[0].ParameterType == socketInformationType);
+            Assert.That(handleRequest, Is.Not.Null,
+                "Ceen.Httpd.HttpServer.AppDomainBridge.HandleRequest(SocketInformation,...) overload not found among: " +
+                string.Join("; ",
+                    handleRequestCandidates.Select(m => $"{m.Name}({string.Join(",", m.GetParameters().Select(p => p.ParameterType.FullName))})")));
+
+            const BindingFlags allStatic = BindingFlags.Public | BindingFlags.NonPublic
+                | BindingFlags.Static;
+            var runClient = httpServerType.GetMethods(allStatic)
+                .FirstOrDefault(m => m.Name == "RunClient"
+                    && m.GetParameters().Length > 0
+                    && m.GetParameters()[0].ParameterType == socketInformationType);
+            Assert.That(runClient, Is.Not.Null,
+                "Ceen.Httpd.HttpServer.RunClient(SocketInformation,...) overload not found.");
+
+            AssertWindowsPlatform(handleRequest!,
+                "Ceen.Httpd.HttpServer.AppDomainBridge.HandleRequest");
+            AssertWindowsPlatform(runClient!,
+                "Ceen.Httpd.HttpServer.RunClient(SocketInformation,...)");
+        }
+    }
+}