1 changed files with 233 additions and 0 deletions
@@ -0,0 +1,233 @@
+# Fresh Start: Approaches to Override /// Comments with DocumentationAttribute
+
+## Goal
+Make `[Documentation]` attribute the **single source of truth** that overrides any existing `///` XML comments, working automatically for both library developers and NuGet package consumers.
+
+---
+
+## Option 1: Roslyn Source Generator (RECOMMENDED) ⭐
+
+### How It Works
+```csharp
+// Original code (what user writes):
+namespace MyNamespace 
+{
+    [Documentation("MyClass", "A cool class")]
+    public class MyClass 
+    {
+        [Documentation("DoWork", "Does the work")]
+        public void DoWork() { }
+    }
+}
+
+// Generated code (MyClass.Documentation.g.cs):
+namespace MyNamespace 
+{
+    /// <summary>A cool class</summary>
+    public partial class MyClass 
+    {
+        /// <summary>Does the work</summary>
+        public partial void DoWork();
+    }
+}
+```
+
+### Pros
+✅ **Standard .NET approach** - Uses official Roslyn APIs
+✅ **Zero setup for consumers** - Packaged as analyzer, auto-runs
+✅ **IDE friendly** - Full IntelliSense support
+✅ **Non-invasive** - Doesn't modify source files
+✅ **Incremental** - Fast compilation with IIncrementalGenerator
+✅ **Easy debugging** - Generated files visible in IDE
+✅ **NuGet ready** - Package as analyzer, include in Documentation package
+
+### Cons
+⚠️ **Requires partial classes** - Classes must be marked `partial`
+⚠️ **Learning curve** - Source generators are complex
+⚠️ **Build-time only** - Not visible until after build
+
+### Implementation
+1. Create `OmegaLeo.HelperLib.SourceGenerator` project
+2. Implement `IIncrementalGenerator`
+3. Find syntax nodes with `DocumentationAttribute`
+4. Generate partial classes with XML doc comments
+5. Package as analyzer with `<PackageReference Include="...SourceGenerator" OutputItemType="Analyzer">`
+6. Include in Documentation package
+
+### Package Structure
+```
+OmegaLeo.HelperLib.SourceGenerator.nupkg
+├── analyzers/dotnet/cs/
+│   └── OmegaLeo.HelperLib.SourceGenerator.dll
+└── build/
+    └── OmegaLeo.HelperLib.SourceGenerator.props
+```
+
+---
+
+## Option 2: Pre-Build File Rewriter
+
+### How It Works
+```csharp
+// Before build:
+[Documentation("MyMethod", "Does work")]
+/// <summary>Old comment</summary>  ← Will be replaced
+public void MyMethod() { }
+
+// After CommentGenerator runs (BEFORE compile):
+[Documentation("MyMethod", "Does work")]
+/// <summary>Does work</summary>  ← New comment from attribute
+public void MyMethod() { }
+```
+
+### Pros
+✅ **Direct control** - Actually modifies source files
+✅ **Works with existing code** - No partial classes needed
+✅ **Visible immediately** - Changes are in source
+✅ **Simple to understand** - Just file modification
+
+### Cons
+❌ **Modifies source files** - Can conflict with version control
+❌ **Timing issues** - Must run before compile, after restore
+❌ **File locks** - Can cause issues with IDEs
+❌ **Consumer complexity** - Hard to package for NuGet users
+❌ **Merge conflicts** - Generated changes in git
+
+---
+
+## Option 3: Hybrid - Source Generator + XML Post-Processor
+
+### How It Works
+1. **Source Generator**: Generates partial classes with /// comments
+2. **XmlDocGenerator**: Post-processes XML files to add examples from attributes
+
+```csharp
+// User writes:
+[Documentation("DoWork", "Does work", null, "// example code")]
+public void DoWork() { }
+
+// Source Generator adds:
+/// <summary>Does work</summary>
+
+// XmlDocGenerator augments XML with:
+<example><![CDATA[// example code]]></example>
+```
+
+### Pros
+✅ **Best of both worlds** - IDE sees comments, XML has examples
+✅ **Clean source** - No manual /// needed
+✅ **Rich documentation** - Full XML in packages
+
+### Cons
+⚠️ **Dual approach** - Two tools to maintain
+⚠️ **Complexity** - More moving parts
+
+---
+
+## Option 4: Roslyn Analyzer + Code Fix
+
+### How It Works
+- Analyzer detects `[Documentation]` without matching `///`
+- Shows warning/info diagnostic
+- Code fix automatically adds `///` from attribute
+- User can apply fix manually or in batch
+
+### Pros
+✅ **IDE integration** - Shows as lightbulb/suggestion
+✅ **User control** - User decides when to apply
+✅ **Standard pattern** - How many .NET tools work
+
+### Cons
+❌ **Manual step** - Not fully automatic
+❌ **User must trigger** - Doesn't help consumers much
+
+---
+
+## Recommendation: Option 1 (Source Generator)
+
+### Why?
+1. **Industry standard** - How modern .NET tools work
+2. **Automatic for consumers** - Zero setup
+3. **IDE support** - Full IntelliSense
+4. **Non-invasive** - No source file modification
+5. **Maintainable** - Clear separation of concerns
+
+### Migration Path
+1. Mark classes as `partial` (one-time change)
+2. Install source generator (packaged with Documentation)
+3. Build project
+4. IDE shows documentation immediately
+
+### For Consumers
+```bash
+# Install package
+dotnet add package OmegaLeo.HelperLib.Documentation
+
+# Write code
+[Documentation("MyMethod", "Cool stuff")]
+public partial class MyClass 
+{
+    public void MyMethod() { }
+}
+
+# Build - source generator runs automatically
+dotnet build
+
+# IDE shows: "Cool stuff" in IntelliSense!
+```
+
+---
+
+## What Needs to Change
+
+### Current State
+- Classes/methods have `[Documentation]` attribute
+- Some have manual `///` comments (duplication)
+- XmlDocGenerator augments compiled XML
+
+### With Source Generator
+- Classes/methods marked `partial`
+- Only `[Documentation]` attribute needed
+- Source generator creates `///` at compile time
+- XmlDocGenerator still augments compiled XML with examples
+
+### File Changes Required
+```csharp
+// Before:
+public class BenchmarkUtility { }
+
+// After:
+public partial class BenchmarkUtility { }  // Add 'partial'
+```
+
+---
+
+## Next Steps
+
+1. ✅ Get user confirmation on approach
+2. Create source generator project
+3. Implement IIncrementalGenerator
+4. Test locally
+5. Package as analyzer
+6. Test with consumer project
+7. Update all classes to partial
+8. Document the change
+
+---
+
+## Questions for User
+
+1. **Are you okay with marking classes as `partial`?**
+   - This is required for source generators
+   - Minimal code change
+   - Standard .NET pattern
+
+2. **Should we keep XmlDocGenerator for code examples?**
+   - Source generator handles /// comments
+   - XmlDocGenerator can add <example> tags to XML
+   - Complementary tools
+
+3. **Any concerns about source generators?**
+   - Build-time dependency
+   - Requires rebuild to see changes
+   - Standard in .NET ecosystem