fix: attribute check now checks immediate type and not any other partials

.github/copilot-instructions.md

@@ -0,0 +1,140 @@
+# GitHub Copilot Instructions for Vogen
+
+This document is aimed at AI agents working on the **Vogen** repository.  The
+codebase is a .NET source‑generator + analyzer that wraps primitives in
+strongly‑typed value objects.  Understanding the structure, build/test
+workflows, and project‑specific conventions will make an agent productive
+quickly.
+
+---
+
+## 🚀 High‑Level Architecture
+
+* **Core library** lives in `src/Vogen`.  It contains the Roslyn
+  source‑generator and analyzer logic.  Look under `Generators` for the
+  template code that emits structs/classes/records, and `Conversions` for the
+  plumbing that handles primitive conversions.
+* **Code fixers** are in `src/Vogen.CodeFixers`; they plug into the validator
+  diagnostics produced by the analyzer.
+* **Packaging** happens in `src/Vogen.Pack`; this project bundles the
+  analyzer/generator dlls for multiple Roslyn versions (`roslyn4.4`,
+  `4.6`, `4.8`, `4.11`, `4.12`) so consumers can reference the correct one.
+* **Shared types** used by tests live in `src/Vogen.SharedTypes`; these are
+  compiled as metadata references when snapshotting across frameworks.
+* **Sample/consumer apps** under `samples/*` and the `Consumers.sln` show
+  real‑world usage (WebApplication, OrleansExample, etc.).
+
+The generator is invoked during normal `dotnet build` on a project that
+contains `[ValueObject]` attributes.  The analyzer emits `VOG###` diagnostics to
+prevent invalid construction.  Codefixers offer automatic fixes.
+
+---
+
+## 🗂 Repository Structure (key folders)
+
+```
+src/            ← core projects (Vogen, CodeFixers, Pack, SharedTypes)
+tests/          ← unit, snapshot, analyzer and consumer tests
+samples/        ← lightweight example applications
+RunSnapshots.ps1← PowerShell helper for resetting/running snapshot tests
+Build.ps1       ← full build-pack-test script used by CI and maintainers
+CONTRIBUTING.md ← developer guidance (tests, thorough mode, etc.)
+```
+
+Snapshots live alongside generated code under `tests/SnapshotTests/snapshots`.
+AnalyzerTests generate code in‑memory and assert diagnostics/solutions.
+ConsumerTests are end‑to‑end projects that reference Vogen via NuGet (see
+`Build.ps1` for how the local package is built and consumed).
+
+---
+
+## 🛠 Developer Workflows
+
+1. **Quick build** – `dotnet build Vogen.sln -c Release` builds the generator,
+   analyzer, codefixers and tests.  `Directory.Build.props` sets
+   `LangVersion=preview`, `TreatWarningsAsErrors`, and common suppression
+   flags.
+2. **Snapshot tests** – run `.\RunSnapshots.ps1` from repo root.  this
+   script cleans snapshot folders, builds with `-p Thorough=true` and runs
+   `dotnet test tests/SnapshotTests/SnapshotTests.csproj`.  Pass
+   `-reset` to delete existing snapshots first.  Add `-p THOROUGH` to the
+   build/test invocation for the full permutation set (used by CI).
+3. **Analyzer tests** – `dotnet test tests/AnalyzerTests/AnalyzerTests.csproj`.
+   These compile generated snippets and assert diagnostics / codefixes.  They
+   depend on `SnapshotTests` for the generated output.
+4. **Consumer / sample validation** – run `Build.ps1` which:
+   * builds the core projects for each Roslyn version;
+   * packs `Vogen.Pack` into a local folder with a unique 999.X version;
+   * restores `Consumers.sln` using `nuget.private.config` pointing at the
+     local package;
+   * builds/tests samples and consumer tests in both Debug and Release;
+   * optionally rebuilds with `DefineConstants="VOGEN_NO_VALIDATION"`.
+5. **Publishing** – `Build.ps1` ends by packing a release NuGet into
+   `./artifacts`.
+
+> **Note:** pull requests should include updated snapshots if the
+> generator output changes; run the reset script and commit the diffs.
+
+---
+
+## 🧪 Testing Conventions
+
+* Tests target multiple TFMs; snapshot project is multi‑targeted
+  (`net461`, `netstandard2.0`, `net8.0` …) to ensure generated code works
+  everywhere.  The code generating the tests lives in `tests/SnapshotTests`.
+* The `THOROUGH` MSBuild property expands the permutation matrix
+  (struct/class/record/readonly, underlying types `int`, `string`, …,
+  conversions, etc.).  It slows down local runs; CI always sets it.
+* `AnalyzerTests` use XUnit attributes and in‑memory compilation helpers
+  (`CompilationHelper.cs`).  They also check codefixers in
+  `Vogen.CodeFixers`.
+* `ConsumerTests` are plain projects referencing the NuGet package; they are
+  rebuilt by `Build.ps1` to exercise packaging scenarios.
+* `tests/Testbench` contains scratch code that developers use when
+  experimenting; not part of CI.
+
+---
+
+## 🔧 Project‑Specific Patterns
+
+* **Generator templates:** strings assembled with `$@` inside classes like
+  `StructGenerator`, `ClassGenerator`, `RecordStructGenerator`.  Helpers in
+  `Util.cs` and the `Conversions` namespace produce small fragments.
+* **Attribute‑driven design:** `[ValueObject]` (in the `Vogen` namespace) is
+  the only public API for consumers.  Additional configuration comes from
+  `[ValueObjectConverter]`, `[ValueObjectTypeAttribute]`, etc.  `GenerationParameters`
+  and `VoWorkItem` carry the state through the generator.
+* **Roslyn versioning:** the `RoslynVersion` MSBuild property is used in
+  `src/Vogen/Vogen.csproj` and `Vogen.CodeFixers.csproj` to produce assemblies
+  that target specific engine versions – this drives the packaging logic.
+* **Compile-time switches:** `VOGEN_NO_VALIDATION` disables the runtime
+  validation code; used in consumer tests.  `THOROUGH` and
+  `ResetSnapshots` control test behaviours.
+* **`Nullable` handling:** the generator has explicit support for nullable
+  underlying types (`string?`, `int?`) using helpers like
+  `Nullable.QuestionMarkForUnderlying` and `WrapBlock`.
+* **Performance-first:** generated types are designed to be as thin as
+  possible; tests under `tests/Vogen.Benchmarks` validate performance.
+* **Style:** the codebase is very terse and uses C#8/9/10/11 features; maintain
+  consistency with existing files when adding or editing generators.
+
+---
+
+## 📌 Integration & External Dependencies
+
+* The only external package references in core code are Roslyn (`Microsoft.CodeAnalysis`)
+  and test frameworks (xUnit, FluentAssertions, etc.).
+* Consumer examples depend on ASP.NET, Orleans, Refit, ServiceStack, etc.
+* CI pipeline (GitHub actions) invokes `Build.ps1` and `RunSnapshots.ps1`.
+
+---
+
+## 👀 Getting Help / Next Steps
+
+If a section here is unclear or you'd like more detail (e.g. typical test
+patterns, how conversions are added, build script flags), let me know and I
+can elaborate or add examples.
+
+---
+
+*Last updated March 2026.*

samples/Vogen.Examples/Types/PartialString.Json.cs

@@ -0,0 +1,5 @@
+namespace Vogen.Examples.Types;
+
+public partial class PartialString
+{
+}

samples/Vogen.Examples/Types/PartialString.cs

@@ -0,0 +1,7 @@
+namespace Vogen.Examples.Types;
+
+[ValueObject<string>]
+public partial class PartialString
+{
+
+}

samples/WebApplication/OrdersController.cs

@@ -1,5 +1,6 @@
 using Microsoft.AspNetCore.Mvc;
 
+[ApiController]
 [Route("api/[controller]")]
 public class OrdersController : ControllerBase
 {
@@ -32,5 +33,12 @@ public IActionResult GetByOrderId(OrderId orderId)
             return new NotFoundResult();
         return Ok(order);
     }
+
+    [HttpPost]
+    [Produces(typeof(Order))]
+    public IActionResult Post([FromBody]OrderId[] orderIds)
+    {
+        return Created();
+    }
 }
 

samples/WebApplication/Program.cs

@@ -26,19 +26,19 @@
 
 
 var builder = Microsoft.AspNetCore.Builder.WebApplication.CreateBuilder(args);
+builder.Services.AddEndpointsApiExplorer();
 
-#if USE_MICROSOFT_OPENAPI_AND_SCALAR
-    builder.Services.AddOpenApi((OpenApiOptions o) =>
-    {
-        o.MapVogenTypesInOpenApiMarkers();
-    });
-#endif
+    #if USE_MICROSOFT_OPENAPI_AND_SCALAR
+        builder.Services.AddOpenApi((OpenApiOptions o) =>
+        {
+            o.MapVogenTypesInOpenApiMarkers();
+        });
+    #endif
 
 
 #if USE_SWASHBUCKLE
 // Add services to the container.
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
-builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen(opt =>
 {
     // the following extension method is available if you specify `GenerateSwashbuckleMappingExtensionMethod` - as shown above

samples/WebApplication/README.md

@@ -11,5 +11,29 @@ You can switch by changing `<OpenApiMode>` in the `.csproj` file to `MicrosoftAn
 or `Swashbuckle-net10`. 
 The launch settings for `MicrosoftAndScalar` is `https openapi and scalar`.
 
+## Run from the command line
+
+The `WebApplication` project uses conditional compilation constants to switch between OpenAPI setups.
+Use the `OpenApiMode` MSBuild property from the command line to set those constants.
+
+### Run with Swashbuckle (`USE_SWASHBUCKLE`)
+
+```bash
+dotnet run --project samples/WebApplication/WebApplication.csproj -p:OpenApiMode=Swashbuckle-net8
+```
+
+```bash
+dotnet run --project samples/WebApplication/WebApplication.csproj -p:OpenApiMode=Swashbuckle-net10
+```
+This will generate the swagger page at `/swagger`, and the OpenApi spec at `/swagger/v1/swagger.json`
+
+### Run with Microsoft OpenAPI + Scalar (`USE_MICROSOFT_OPENAPI_AND_SCALAR`)
+
+```bash
+dotnet run --project samples/WebApplication/WebApplication.csproj -p:OpenApiMode=MicrosoftAndScalar
+```
+
+This will generated the OpenApi spec at `/openapi/v1.json`
+
 The companion project to this is `WebApplicationConsumer` which demonstrates how to consume an API that uses value 
-object as parameters.
+object as parameters.

samples/WebApplication/WebApplication.csproj

@@ -4,7 +4,7 @@
         <Nullable>enable</Nullable>
         <ImplicitUsings>enable</ImplicitUsings>
         <UseLocallyBuiltPackage>true</UseLocallyBuiltPackage>
-        <OpenApiMode>Swashbuckle-net8</OpenApiMode>
+        <OpenApiMode>MicrosoftAndScalar</OpenApiMode>
     </PropertyGroup>
 
     <PropertyGroup Condition=" '$(OpenApiMode)' == 'Swashbuckle-net8'">

src/Vogen/GenerateCodeForAspNetCoreOpenApiSchema.cs

@@ -134,6 +134,38 @@ private static void MapWorkItemsForOpenApi(IEnumerable<Item> workItems, StringBu
 
             sb.Append(_indent, 3).AppendLine($"}}");
             sb.AppendLine();
+
+            // array handling
+            sb.Append(_indent, 3).AppendLine($"if (context.JsonTypeInfo.Type.IsArray && context.JsonTypeInfo.Type.GetElementType() == typeof({typeExpression}))");
+            sb.Append(_indent, 3).AppendLine("{");
+            if (v is OpenApiVersionBeingUsed.One)
+            {
+                sb.Append(_indent, 4).AppendLine("schema.Type = \"array\";");
+                sb.Append(_indent, 4).AppendLine($"schema.Items = new Microsoft.OpenApi.Models.OpenApiSchema {{ Type = \"{typeAndPossibleFormat.Type}\"{(string.IsNullOrEmpty(typeAndPossibleFormat.Format) ? "" : $", Format = \"{typeAndPossibleFormat.Format}\"")} }};");
+            }
+            if (v is OpenApiVersionBeingUsed.TwoPlus)
+            {
+                sb.Append(_indent, 4).AppendLine("schema.Type = Microsoft.OpenApi.JsonSchemaType.Array;");
+                sb.Append(_indent, 4).AppendLine($"schema.Items = new Microsoft.OpenApi.OpenApiSchema {{ Type = Microsoft.OpenApi.JsonSchemaType.{typeAndPossibleFormat.JsonSchemaType}{(string.IsNullOrEmpty(typeAndPossibleFormat.Format) ? "" : $", Format = \"{typeAndPossibleFormat.Format}\"")} }};");
+            }
+            sb.Append(_indent, 3).AppendLine("}");
+            sb.AppendLine();
+
+            // generic collection handling (List<>, IEnumerable<>, etc.)
+            sb.Append(_indent, 3).AppendLine($"if (context.JsonTypeInfo.Type.IsGenericType && context.JsonTypeInfo.Type.GetGenericArguments().Length == 1 && context.JsonTypeInfo.Type.GetGenericArguments()[0] == typeof({typeExpression}))");
+            sb.Append(_indent, 3).AppendLine("{");
+            if (v is OpenApiVersionBeingUsed.One)
+            {
+                sb.Append(_indent, 4).AppendLine("schema.Type = \"array\";");
+                sb.Append(_indent, 4).AppendLine($"schema.Items = new Microsoft.OpenApi.Models.OpenApiSchema {{ Type = \"{typeAndPossibleFormat.Type}\"{(string.IsNullOrEmpty(typeAndPossibleFormat.Format) ? "" : $", Format = \"{typeAndPossibleFormat.Format}\"")} }};");
+            }
+            if (v is OpenApiVersionBeingUsed.TwoPlus)
+            {
+                sb.Append(_indent, 4).AppendLine("schema.Type = Microsoft.OpenApi.JsonSchemaType.Array;");
+                sb.Append(_indent, 4).AppendLine($"schema.Items = new Microsoft.OpenApi.OpenApiSchema {{ Type = Microsoft.OpenApi.JsonSchemaType.{typeAndPossibleFormat.JsonSchemaType}{(string.IsNullOrEmpty(typeAndPossibleFormat.Format) ? "" : $", Format = \"{typeAndPossibleFormat.Format}\"")} }};");
+            }
+            sb.Append(_indent, 3).AppendLine("}");
+            sb.AppendLine();
         }
     }
 

src/Vogen/GenerateCodeForBsonSerializers.cs

@@ -33,7 +33,7 @@ public static void GenerateForApplicableValueObjects(SourceProductionContext con
 
             var filename = new Filename(eachWrapper.WrapperType.ToDisplayString() + "_bson.g.cs");
 
-            Util.TryWriteUsingUniqueFilename(filename, context, Util.FormatSource(eachGenerated));
+            Util.AddSourceToContext(filename, context, Util.FormatSource(eachGenerated));
         }
 
         WriteRegistration(applicableWrappers, compilation, context);
@@ -84,7 +84,7 @@ private static void GenerateForMarkerClass(SourceProductionContext context, Mark
 
         string filename = Util.GetLegalFilenameForMarkerClass(markerClass.MarkerClassSymbol, ConversionMarkerKind.Bson);
 
-        Util.TryWriteUsingUniqueFilename(filename, context, Util.FormatSource(sourceCode));
+        Util.AddSourceToContext(filename, context, Util.FormatSource(sourceCode));
 
         return;
 
@@ -163,7 +163,7 @@ public static void TryRegister() { }
               }
               """;
 
-        Util.TryWriteUsingUniqueFilename(classNameForRegistering, context, Util.FormatSource(source));
+        Util.AddSourceToContext(classNameForRegistering, context, Util.FormatSource(source));
         return;
 
         string ClassNameForRegistering()

src/Vogen/GenerateCodeForEfCoreMarkers.cs

@@ -74,7 +74,7 @@ private static void WriteEachIfNeeded(SourceProductionContext context, Conversio
 
         string filename = Util.GetLegalFilenameForMarkerClass(markerClass.MarkerClassSymbol, markerClass.VoSymbol, markerClass.Kind);
 
-        Util.TryWriteUsingUniqueFilename(filename, context, sourceText);
+        Util.AddSourceToContext(filename, context, sourceText);
     }
 
     private static void StoreExtensionMethodToRegisterAllInMarkerClass(
@@ -121,7 +121,7 @@ private static void StoreExtensionMethodToRegisterAllInMarkerClass(
 
         var filename = Util.GetLegalFilenameForMarkerClass(markerSymbol, ConversionMarkerKind.EFCore);
 
-        Util.TryWriteUsingUniqueFilename(filename, context, sourceText);
+        Util.AddSourceToContext(filename, context, sourceText);
 
         return;
 

src/Vogen/GenerateCodeForMessagePack.cs

@@ -53,7 +53,7 @@ private static void GenerateForAMarkerClass(SourceProductionContext context, Mar
 
         string filename = Util.GetLegalFilenameForMarkerClass(markerClass.MarkerClassSymbol, ConversionMarkerKind.MessagePack);
 
-        Util.TryWriteUsingUniqueFilename(filename, context, sourceText);
+        Util.AddSourceToContext(filename, context, sourceText);
 
         return;
 
@@ -124,7 +124,7 @@ public static void GenerateForApplicableValueObjects(SourceProductionContext con
         {
             SourceText sourceText = Util.FormatSource(eachToWrite.SourceCode);
 
-            Util.TryWriteUsingUniqueFilename(eachToWrite.Filename, context, sourceText);
+            Util.AddSourceToContext(eachToWrite.Filename, context, sourceText);
         }
     }
 

src/Vogen/GenerateCodeForOpenApiSchemaCustomization.cs

@@ -209,6 +209,18 @@ private static void MapWorkItems(IEnumerable<Item> workItems, StringBuilder sb,
 
                         sb.AppendLine(
                             $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<{{fqn}}>(o, () => new global::Microsoft.OpenApi.Models.OpenApiSchema { {{typeText}}{{formatText}}{{nullableText}} });""");
+                        // also map arrays and generic collection wrappers; this keeps the
+                        // item schema information instead of letting it default to an
+                        // untyped array.
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<{{fqn}}[]>(o, () => new global::Microsoft.OpenApi.Models.OpenApiSchema { Type = "array", Items = new global::Microsoft.OpenApi.Models.OpenApiSchema { {{typeText}}{{formatText}}{{nullableText}} } });"""
+                        );
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<global::System.Collections.Generic.List<{{fqn}}>>(o, () => new global::Microsoft.OpenApi.Models.OpenApiSchema { Type = "array", Items = new global::Microsoft.OpenApi.Models.OpenApiSchema { {{typeText}}{{formatText}}{{nullableText}} } });"""
+                        );
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<global::System.Collections.Generic.IEnumerable<{{fqn}}>>(o, () => new global::Microsoft.OpenApi.Models.OpenApiSchema { Type = "array", Items = new global::Microsoft.OpenApi.Models.OpenApiSchema { {{typeText}}{{formatText}}{{nullableText}} } });"""
+                        );
                         break;
                     }
                 case OpenApiVersionBeingUsed.TwoPlus:
@@ -219,8 +231,19 @@ private static void MapWorkItems(IEnumerable<Item> workItems, StringBuilder sb,
                             typeText += " | global::Microsoft.OpenApi.JsonSchemaType.Null";
                         }
 
+                        var array =
+                            $$"""new global::Microsoft.OpenApi.OpenApiSchema { Type = global::Microsoft.OpenApi.JsonSchemaType.Array, Items = new global::Microsoft.OpenApi.OpenApiSchema { {{typeText}}{{formatText}} } }""";
                         sb.AppendLine(
                             $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<{{fqn}}>(o, () => new global::Microsoft.OpenApi.OpenApiSchema { {{typeText}}{{formatText}} });""");
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<{{fqn}}[]>(o, () => {{array}});"""
+                        );
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<global::System.Collections.Generic.List<{{fqn}}>>(o, () => {{array}});"""
+                        );
+                        sb.AppendLine(
+                            $$"""global::Microsoft.Extensions.DependencyInjection.SwaggerGenOptionsExtensions.MapType<global::System.Collections.Generic.IEnumerable<{{fqn}}>>(o, () => {{array}});"""
+                        );
                         break;
                     }
             }

src/Vogen/GenerateCodeForOrleansSerializers.cs

@@ -24,7 +24,7 @@ private static void WriteSerializer(SerializerEntry entry, SourceProductionConte
     {
         SourceText sourceText = SourceText.From(entry.SourceCode, Encoding.UTF8);
 
-        Util.TryWriteUsingUniqueFilename(entry.Filename, context, sourceText);
+        Util.AddSourceToContext(entry.Filename, context, sourceText);
     }
 
     public record SerializerEntry(string Filename, string SourceCode);