C#: Add a Roslyn analyzer for global classes

Co-Authored-By: Raul Santos <raulsntos@gmail.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators/GlobalClassAnalyzer.cs b/modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators/GlobalClassAnalyzer.cs
new file mode 100644
index 0000000000..bcb35dae8a
--- /dev/null
+++ b/modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators/GlobalClassAnalyzer.cs
@@ -0,0 +1,42 @@
+using System.Collections.Immutable;
+using System.Linq;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace Godot.SourceGenerators
+{
+    [DiagnosticAnalyzer(LanguageNames.CSharp)]
+    public class GlobalClassAnalyzer : DiagnosticAnalyzer
+    {
+        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
+            => ImmutableArray.Create(
+                Common.GlobalClassMustDeriveFromGodotObjectRule,
+                Common.GlobalClassMustNotBeGenericRule);
+
+        public override void Initialize(AnalysisContext context)
+        {
+            context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
+            context.RegisterSyntaxNodeAction(AnalyzeNode, SyntaxKind.ClassDeclaration);
+        }
+
+        private void AnalyzeNode(SyntaxNodeAnalysisContext context)
+        {
+            var typeClassDecl = (ClassDeclarationSyntax)context.Node;
+
+            // Return if not a type symbol or the type is not a global class.
+            if (context.ContainingSymbol is not INamedTypeSymbol typeSymbol ||
+                !typeSymbol.GetAttributes().Any(a => a.AttributeClass?.IsGodotGlobalClassAttribute() ?? false))
+                return;
+
+            if (typeSymbol.IsGenericType)
+                Common.ReportGlobalClassMustNotBeGeneric(context, typeClassDecl, typeSymbol);
+
+            if (!typeSymbol.InheritsFrom("GodotSharp", GodotClasses.GodotObject))
+                Common.ReportGlobalClassMustDeriveFromGodotObject(context, typeClassDecl, typeSymbol);
+        }
+    }
+}