refactor: generator

Optify.Tests/DebugGenerator.cs

@@ -12,7 +12,10 @@ public Task Should_allow_the_debugger_in_the_generator()
         var compilation = CSharpCompilation
             .Create("CSharpCodeGen.GenerateAssembly")
             .AddSyntaxTrees(CSharpSyntaxTree.ParseText(DebugGeneratorSource.Source))
-            .AddReferences(MetadataReference.CreateFromFile(typeof(object).Assembly.Location))
+            .AddReferences(
+                MetadataReference.CreateFromFile(typeof(object).Assembly.Location),
+                MetadataReference.CreateFromFile(typeof(OptifyOptionsAttribute).Assembly.Location)
+            )
             .WithOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
         var driver = CSharpGeneratorDriver
             .Create(generator)
@@ -30,7 +33,8 @@ file static class DebugGeneratorSource
         using Optify;
         namespace CSharpCodeGen;
 
-        [OptifyOptions] public class Config;
+        [OptifyOptions]
+        public class Config;
 
         [OptifyOptions(SectionName = "OverrideNamedDummySettings")]
         public class NamedDummySettings;

Optify/OptifyGenerator.cs

@@ -17,24 +17,17 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                 if (ctx.TargetSymbol is not INamedTypeSymbol target)
                     return new OptionsTypeToRegister();
 
-                var fullName = target.ToDisplayString(
-                    SymbolDisplayFormat.FullyQualifiedFormat.WithGlobalNamespaceStyle(
-                        SymbolDisplayGlobalNamespaceStyle.Omitted
-                    )
-                );
-                var sectionNameArg = ctx.Attributes[0]
-                    .NamedArguments.FirstOrDefault(static x => x.Key == nameof(OptifyOptionsAttribute.SectionName));
-                var sectionName = sectionNameArg.Value.Value as string ?? ctx.TargetSymbol.Name;
-                var validationArg = ctx.Attributes[0]
-                    .NamedArguments.FirstOrDefault(static x => x.Key == nameof(OptifyOptionsAttribute.Validation));
-                var validation = validationArg.Value.Value is int v ? v : 0;
-
-                return new OptionsTypeToRegister(sectionName, fullName, (ValidationFlag)validation);
+                // At this point, ctx.Attributes *only* contains OptifyOptionsAttribute, even
+                // when other attributes are on the type. A user should receive a compiler error
+                // CS0579 if they added more than one [OptifyOptions]. However, generated source
+                // may be able to bypass that. In such a case, we're just going to assume
+                // that we'll take the first one.
+                return new OptionsTypeToRegister(ctx.Attributes[0], target);
             }
         );
 
         context.RegisterSourceOutput(
-            provider.Where(static opt => !opt.IsNull).Collect(),
+            provider.Where(static opt => opt.IsValid).Collect(),
             static (spc, types) =>
             {
                 spc.AddSource(OptifyRegistrationSource.Filename, OptifyRegistrationSource.GenerateSource(types));

Optify/OptionsTypeToRegister.cs

@@ -1,21 +1,36 @@
+using Microsoft.CodeAnalysis;
+
 namespace Optify;
 
 public readonly record struct OptionsTypeToRegister
 {
-    public readonly bool IsNull;
-    public readonly string SectionName = string.Empty;
-    public readonly string FullName = string.Empty;
-    public readonly ValidationFlag Validation = 0;
+    public bool IsValid { get; }
+    public string SectionName { get; } = string.Empty;
+    public string FullName { get; } = string.Empty;
+    public ValidationFlag Validation { get; }
 
-    public OptionsTypeToRegister(string sectionName, string fullName, ValidationFlag validation)
+    public OptionsTypeToRegister(AttributeData attributeData, INamedTypeSymbol targetType)
     {
-        SectionName = sectionName;
-        FullName = fullName;
-        Validation = validation;
+        FullName = targetType.ToDisplayString();
+        SectionName = targetType.Name;
+        IsValid = true;
+
+        foreach (var argument in attributeData.NamedArguments)
+        {
+            switch (argument.Key)
+            {
+                case nameof(OptifyOptionsAttribute.SectionName):
+                    SectionName = argument.Value.Value as string ?? targetType.Name;
+                    break;
+                case nameof(OptifyOptionsAttribute.Validation):
+                    Validation = argument.Value.Value is int intValue ? (ValidationFlag)intValue : 0;
+                    break;
+            }
+        }
     }
 
     public OptionsTypeToRegister()
     {
-        IsNull = true;
+        IsValid = false;
     }
 }