Add DP033 duplicate-key scenario (S4) to plugin assemblies sample

DesignPatterns.Samples.PluginAssemblies/Providers.AlphaConflict/ConflictCard.cs

@@ -0,0 +1,10 @@
+using DesignPatterns.Behavioral;
+using PluginAssemblies.Sample.Contracts;
+
+namespace PluginAssemblies.Sample.Providers.AlphaConflict;
+
+[RegisterStrategy<ICardMotion>("alpha")]
+public sealed class ConflictCard : ICardMotion
+{
+    public string ProviderName => "alpha-conflict";
+}

DesignPatterns.Samples.PluginAssemblies/Providers.AlphaConflict/DesignPatterns.Samples.PluginAssemblies.Providers.AlphaConflict.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>PluginAssemblies.Sample.Providers.AlphaConflict</RootNamespace>
+    <DesignPatternsPluginProvider>true</DesignPatternsPluginProvider>
+    <Description>Duplicate alpha key provider for DP033 demo (plugin-assemblies sample).</Description>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Contracts\DesignPatterns.Samples.PluginAssemblies.Contracts.csproj" />
+  </ItemGroup>
+
+</Project>

DesignPatterns.Samples.PluginAssemblies/README.md

@@ -9,10 +9,12 @@ Maps to [PluginAssemblies.md](https://github.com/Skymly/DesignPatterns/blob/main
 ```
 Contracts/                 Shared interfaces (no provider code)
 Providers.Alpha/           Card motion — key "alpha"
+Providers.AlphaConflict/   Card motion — duplicate key "alpha" (DP033 demo only)
 Providers.Beta/            Card motion — key "beta" (optional reference)
 Providers.Gamma/           FC control + error — companion key "gamma"
 Host/                      Autofac host (references Alpha + Gamma, not Beta)
 Scenarios.InvalidKey/      DP025 compile-time failure demo
+Scenarios.DuplicateKey/    DP033 compile-time failure demo
 ```
 
 Each provider assembly emits its own `{Contract}Registry` in the **contract namespace** (e.g. `PluginAssemblies.Sample.Contracts.CardMotionRegistry` inside `Providers.Alpha.dll`).
@@ -24,11 +26,14 @@ Each provider assembly emits its own `{Contract}Registry` in the **contract name
 | **S1** | `dotnet run --project Host` | Starts; prints `Card=alpha`; `CardMotionRegistry.Keys` contains `alpha`, not `beta` |
 | **S2** | `dotnet run --project Host -- s2` | Exit code 1; `App.config` key `CardMissing=beta` resolves via `RegistryConfiguration` but `beta` is not registered (Providers.Beta not referenced) |
 | **S3** | `dotnet test` in sibling DesignPatterns repo (`UnknownRegistryKeyAnalyzerTests`) or IDE on `Scenarios.InvalidKey` | Diagnostic **DP025** for unknown literal key |
+| **S4** | `dotnet test` in sibling DesignPatterns repo (`CrossAssemblyRegistryKeyAnalyzerTests`) or IDE on `Scenarios.DuplicateKey` | Diagnostic **DP033** when Alpha and AlphaConflict both register `alpha` |
 
 `Host/App.config` selects `Card=alpha` and `FC=gamma` for S1. The host uses `DesignPatterns.Extensions.AppSettings.RegistryConfiguration` to map those keys to strategy registries (`CardMissing=beta` drives S2).
 
 `Scenarios.InvalidKey/InvalidKeyUsage.cs` shows the invalid literal pattern; DP025 is enforced by the DesignPatterns analyzer (IDE or NuGet package). Local sibling `ProjectReference` builds may not surface Info-level diagnostics on the command line — CI runs the analyzer unit test instead.
 
+`Scenarios.DuplicateKey` references **Providers.Alpha** and **Providers.AlphaConflict** (both register `ICardMotion` key `alpha`). DP033 is an **Error**; IDE or command-line builds with analyzers should fail. CI falls back to `CrossAssemblyRegistryKeyAnalyzerTests` when the demo project build does not surface DP033.
+
 ## Prerequisites
 
 Sibling [DesignPatterns](https://github.com/Skymly/DesignPatterns) clone with `DesignPatterns.Extensions.Autofac` and `DesignPatterns.Extensions.AppSettings` (merged on `main`).
@@ -40,4 +45,4 @@ dotnet run --project DesignPatterns.Samples.PluginAssemblies/Host -c Release
 
 ## CI
 
-`./build.ps1 --target Ci` builds the host, runs S1, asserts S2 failure output, and runs the sibling DesignPatterns **DP025** analyzer test for S3.
+`./build.ps1 --target Ci` builds the host, runs S1, asserts S2 failure output, and runs sibling DesignPatterns analyzer tests for S3 (DP025) and S4 (DP033).

DesignPatterns.Samples.PluginAssemblies/Scenarios.DuplicateKey/DesignPatterns.Samples.PluginAssemblies.Scenarios.DuplicateKey.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>PluginAssemblies.Sample.Scenarios.DuplicateKey</RootNamespace>
+    <DesignPatternsPluginAnalyzerDemo>true</DesignPatternsPluginAnalyzerDemo>
+    <Description>Compile-time DP033 demo for the plugin-assemblies sample (see README; CI uses analyzer tests).</Description>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Contracts\DesignPatterns.Samples.PluginAssemblies.Contracts.csproj" />
+    <ProjectReference Include="..\Providers.Alpha\DesignPatterns.Samples.PluginAssemblies.Providers.Alpha.csproj" />
+    <ProjectReference Include="..\Providers.AlphaConflict\DesignPatterns.Samples.PluginAssemblies.Providers.AlphaConflict.csproj" />
+  </ItemGroup>
+
+</Project>

DesignPatterns.Samples.PluginAssemblies/Scenarios.DuplicateKey/DuplicateKeyUsage.cs

@@ -0,0 +1,12 @@
+namespace PluginAssemblies.Sample.Scenarios.DuplicateKey;
+
+/// <summary>
+/// Illustrates DP033: the same strategy key for one contract in multiple referenced provider assemblies.
+/// See sibling DesignPatterns repo <c>CrossAssemblyRegistryKeyAnalyzerTests</c>; CI runs that test for S4.
+/// </summary>
+public static class DuplicateKeyUsage
+{
+    public static void HostReferencesConflictingProviders()
+    {
+    }
+}

build/Program.cs

@@ -37,6 +37,9 @@ static readonly (string RelativePath, bool RunAfterBuild)[] SampleProjects =
     AbsolutePath PluginAssembliesInvalidKeyProject =>
         Root / "DesignPatterns.Samples.PluginAssemblies/Scenarios.InvalidKey/DesignPatterns.Samples.PluginAssemblies.Scenarios.InvalidKey.csproj";
 
+    AbsolutePath PluginAssembliesDuplicateKeyProject =>
+        Root / "DesignPatterns.Samples.PluginAssemblies/Scenarios.DuplicateKey/DesignPatterns.Samples.PluginAssemblies.Scenarios.DuplicateKey.csproj";
+
     AbsolutePath DesignPatternsAnalyzerTestsProject =>
         Root / "../DesignPatterns/tests/DesignPatterns.Analyzers.Tests/DesignPatterns.Analyzers.Tests.csproj";
 
@@ -72,6 +75,7 @@ void RunPluginAssembliesScenarios()
     {
         Assert.FileExists(PluginAssembliesHostProject, $"Sample project not found: {PluginAssembliesHostProject}");
         Assert.FileExists(PluginAssembliesInvalidKeyProject, $"Sample project not found: {PluginAssembliesInvalidKeyProject}");
+        Assert.FileExists(PluginAssembliesDuplicateKeyProject, $"Sample project not found: {PluginAssembliesDuplicateKeyProject}");
 
         DotNetBuild(s => s
             .SetProjectFile(PluginAssembliesHostProject)
@@ -110,6 +114,19 @@ void RunPluginAssembliesScenarios()
             .SetProjectFile(DesignPatternsAnalyzerTestsProject)
             .SetConfiguration(Configuration)
             .SetFilter("FullyQualifiedName~UnknownRegistryKeyAnalyzerTests.ReportsDp025WhenStrategyRegistryKeyIsUnknown"));
+
+        var duplicateKeyBuild = StartDotNet(
+            $"build \"{PluginAssembliesDuplicateKeyProject}\" -c {Configuration}",
+            Root);
+        if (duplicateKeyBuild.ExitCode != 0 && duplicateKeyBuild.Output.Contains("DP033", StringComparison.Ordinal))
+        {
+            return;
+        }
+
+        DotNetTest(s => s
+            .SetProjectFile(DesignPatternsAnalyzerTestsProject)
+            .SetConfiguration(Configuration)
+            .SetFilter("FullyQualifiedName~CrossAssemblyRegistryKeyAnalyzerTests.ReportsDp033WhenSameStrategyKeyExistsInTwoReferencedAssemblies"));
     }
 
     static (int ExitCode, string Output) StartDotNet(string arguments, AbsolutePath workingDirectory)