Introduce NINVK005 and NINVK006 diagnostics

* NINVK005: Interface has no valid methods to generate

* NINVK006: Missing library name in [NativeImport] attribute

Author: Cheatoid

NativeInvoke/AnalyzerReleases.Shipped.md

@@ -1,4 +1,4 @@
-; Shipped analyzer releases
+; Shipped analyzer releases
 ; https://github.com/dotnet/roslyn/blob/main/src/RoslynAnalyzers/Microsoft.CodeAnalysis.Analyzers/ReleaseTrackingAnalyzers.Help.md
 
 ## 1.0.0
@@ -7,7 +7,17 @@
 
 Rule ID | Category | Severity | Notes
 --------|----------|----------|-------
-NINVK001 | NativeInvoke | Error | Diagnostics
-NINVK002 | NativeInvoke | Error | Diagnostics
-NINVK003 | NativeInvoke | Error | Diagnostics
-NINVK004 | NativeInvoke | Error | Diagnostics
+NINVK001 | NativeInvoke | Error | Type must be partial to use [NativeImport]
+NINVK002 | NativeInvoke | Error | Property must be static partial to use [NativeImport]
+NINVK003 | NativeInvoke | Error | Property type must be interface to use [NativeImport]
+NINVK004 | NativeInvoke | Error | Method has non-blittable signature
+
+
+## 1.3.5
+
+### New Rules
+
+Rule ID | Category | Severity | Notes
+--------|----------|----------|-------
+NINVK005 | NativeInvoke | Warning | Interface has no valid methods to generate
+NINVK006 | NativeInvoke | Error | Missing library name in [NativeImport] attribute

NativeInvoke/Generator/Diagnostics.cs

@@ -33,4 +33,20 @@ internal static partial class Diagnostics
     category: "NativeInvoke",
     defaultSeverity: DiagnosticSeverity.Error,
     isEnabledByDefault: true);
+
+  public static readonly DiagnosticDescriptor EmptyInterface = new(
+    id: "NINVK005",
+    title: "Interface has no valid methods",
+    messageFormat: "Interface '{0}' has no valid methods to generate (ensure the interface contains at least one method)",
+    category: "NativeInvoke",
+    defaultSeverity: DiagnosticSeverity.Warning,
+    isEnabledByDefault: true);
+
+  public static readonly DiagnosticDescriptor MissingLibraryName = new(
+    id: "NINVK006",
+    title: "Missing library name",
+    messageFormat: "[NativeImport] attribute requires a library name (provide a valid library name via the constructor parameter)",
+    category: "NativeInvoke",
+    defaultSeverity: DiagnosticSeverity.Error,
+    isEnabledByDefault: true);
 }

NativeInvoke/Generator/NativeImportGenerator.cs

@@ -102,11 +102,27 @@ private static void GenerateForProperty(
     Debugger.Launch();
 #endif
 
+    // Validate library name is provided
+    if (pAttr.ConstructorArguments.Length == 0)
+    {
+      spc.ReportDiagnostic(Diagnostic.Create(
+        Diagnostics.MissingLibraryName,
+        prop.Locations[0]));
+      return;
+    }
+    var libraryName = pAttr.ConstructorArguments[0].Value as string;
+    if (string.IsNullOrEmpty(libraryName))
+    {
+      spc.ReportDiagnostic(Diagnostic.Create(
+        Diagnostics.MissingLibraryName,
+        prop.Locations[0]));
+      return;
+    }
+
     // Attribute data
     NativeImportAttribute nativeImportAttr;
     {
       var temp = new NativeImportAttribute(string.Empty); // Temporary instance to get the default values
-      var libraryName = (string?)pAttr.ConstructorArguments[0].Value ?? "__Internal"; // TODO/FIXME: Report a diagnostic
       var enforceBlittable = (bool)(pAttr.NamedArguments
         .FirstOrDefault(static kv => kv.Key == nameof(NativeImportAttribute.EnforceBlittable))
         .Value.Value ?? temp.EnforceBlittable);
@@ -131,7 +147,7 @@ private static void GenerateForProperty(
       var symbolSuffix = (pAttr.NamedArguments
         .FirstOrDefault(static kv => kv.Key == nameof(NativeImportAttribute.SymbolSuffix))
         .Value.Value ?? temp.SymbolSuffix) as string;
-      nativeImportAttr = new NativeImportAttribute(libraryName)
+      nativeImportAttr = new NativeImportAttribute(libraryName!)
       {
         EnforceBlittable = enforceBlittable,
         ExplicitOnly = explicitOnly,
@@ -254,6 +270,14 @@ private static void GenerateForProperty(
       // Generate a file per container type
       spc.AddSource($"{containingType.Name}.{prop.Name}-{Guid.NewGuid():N}.g.cs", source); // Append Guid to avoid collisions, just in case
     }
+    else
+    {
+      // Report warning for empty interfaces
+      spc.ReportDiagnostic(Diagnostic.Create(
+        Diagnostics.EmptyInterface,
+        prop.Locations[0],
+        iface.Name));
+    }
   }
 
   private static string ResolveMethodEntryPoint(string? entryPoint, string methodName, string? symbolPrefix, string? symbolSuffix)