Improve custom filtering support in TransitiveMembersGenerator<TInfo>

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/INotifyPropertyChangedGenerator.cs

@@ -2,14 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using CommunityToolkit.Mvvm.SourceGenerators.Diagnostics;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
@@ -30,11 +28,18 @@ public sealed class INotifyPropertyChangedGenerator : TransitiveMembersGenerator
     }
 
     /// <inheritdoc/>
-    protected override INotifyPropertyChangedInfo GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData)
+    protected override IncrementalValuesProvider<(INamedTypeSymbol Symbol, INotifyPropertyChangedInfo Info)> GetInfo(
+        IncrementalGeneratorInitializationContext context,
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, AttributeData AttributeData)> source)
     {
-        bool includeAdditionalHelperMethods = attributeData.GetNamedArgument<bool>("IncludeAdditionalHelperMethods", true);
+        static INotifyPropertyChangedInfo GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData)
+        {
+            bool includeAdditionalHelperMethods = attributeData.GetNamedArgument<bool>("IncludeAdditionalHelperMethods", true);
 
-        return new(includeAdditionalHelperMethods);
+            return new(includeAdditionalHelperMethods);
+        }
+
+        return source.Select(static (item, _) => (item.Symbol, GetInfo(item.Symbol, item.AttributeData)));
     }
 
     /// <inheritdoc/>

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableObjectGenerator.cs

@@ -28,9 +28,11 @@ public sealed class ObservableObjectGenerator : TransitiveMembersGenerator<objec
     }
 
     /// <inheritdoc/>
-    protected override object? GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData)
+    protected override IncrementalValuesProvider<(INamedTypeSymbol Symbol, object? Info)> GetInfo(
+        IncrementalGeneratorInitializationContext context,
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, AttributeData AttributeData)> source)
     {
-        return null;
+        return source.Select(static (item, _) => (item.Symbol, (object?)null));
     }
 
     /// <inheritdoc/>

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableRecipientGenerator.cs

@@ -30,18 +30,25 @@ public sealed class ObservableRecipientGenerator : TransitiveMembersGenerator<Ob
     }
 
     /// <inheritdoc/>
-    protected override ObservableRecipientInfo GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData)
+    protected override IncrementalValuesProvider<(INamedTypeSymbol Symbol, ObservableRecipientInfo Info)> GetInfo(
+        IncrementalGeneratorInitializationContext context,
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, AttributeData AttributeData)> source)
     {
-        string typeName = typeSymbol.Name;
-        bool hasExplicitConstructors = !(typeSymbol.InstanceConstructors.Length == 1 && typeSymbol.InstanceConstructors[0] is { Parameters.IsEmpty: true, IsImplicitlyDeclared: true });
-        bool isAbstract = typeSymbol.IsAbstract;
-        bool isObservableValidator = typeSymbol.InheritsFrom("global::CommunityToolkit.Mvvm.ComponentModel.ObservableValidator");
+        static ObservableRecipientInfo GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData)
+        {
+            string typeName = typeSymbol.Name;
+            bool hasExplicitConstructors = !(typeSymbol.InstanceConstructors.Length == 1 && typeSymbol.InstanceConstructors[0] is { Parameters.IsEmpty: true, IsImplicitlyDeclared: true });
+            bool isAbstract = typeSymbol.IsAbstract;
+            bool isObservableValidator = typeSymbol.InheritsFrom("global::CommunityToolkit.Mvvm.ComponentModel.ObservableValidator");
 
-        return new(
-            typeName,
-            hasExplicitConstructors,
-            isAbstract,
-            isObservableValidator);
+            return new(
+                typeName,
+                hasExplicitConstructors,
+                isAbstract,
+                isObservableValidator);
+        }
+
+        return source.Select(static (item, _) => (item.Symbol, GetInfo(item.Symbol, item.AttributeData)));
     }
 
     /// <inheritdoc/>

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/TransitiveMembersGenerator.cs

@@ -80,13 +80,15 @@ public abstract partial class TransitiveMembersGenerator<TInfo> : IIncrementalGe
                 static (context, _) => (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!);
 
         // Filter the types with the target attribute
-        IncrementalValuesProvider<(INamedTypeSymbol Symbol, TInfo Info)> typeSymbolsWithInfo =
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, AttributeData AttributeData)> typeSymbolsWithAttributeData =
             typeSymbols
             .Select((item, _) => (
                 Symbol: item,
                 Attribute: item.GetAttributes().FirstOrDefault(a => a.AttributeClass?.HasFullyQualifiedName(this.attributeType) == true)))
-            .Where(static item => item.Attribute is not null)!
-            .Select((item, _) => (item.Symbol, GetInfo(item.Symbol, item.Attribute!)));
+            .Where(static item => item.Attribute is not null)!;
+
+        // Transform the input data
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, TInfo Info)> typeSymbolsWithInfo = GetInfo(context, typeSymbolsWithAttributeData);
 
         // Filter by language version
         context.FilterWithLanguageVersion(ref typeSymbolsWithInfo, LanguageVersion.CSharp8, UnsupportedCSharpLanguageVersionError);
@@ -129,12 +131,14 @@ public abstract partial class TransitiveMembersGenerator<TInfo> : IIncrementalGe
     }
 
     /// <summary>
-    /// Gets an info model from a retrieved <see cref="AttributeData"/> instance.
+    /// Gathers info from a source <see cref="IncrementalValuesProvider{TValues}"/> input.
     /// </summary>
-    /// <param name="typeSymbol">The <see cref="INamedTypeSymbol"/> instance for the target type.</param>
-    /// <param name="attributeData">The input <see cref="AttributeData"/> to get info from.</param>
-    /// <returns>A <typeparamref name="TInfo"/> instance with data extracted from <paramref name="attributeData"/>.</returns>
-    protected abstract TInfo GetInfo(INamedTypeSymbol typeSymbol, AttributeData attributeData);
+    /// <param name="context">The <see cref="IncrementalGeneratorInitializationContext"/> instance in use.</param>
+    /// <param name="source">The source <see cref="IncrementalValuesProvider{TValues}"/> input.</param>
+    /// <returns>A transformed <see cref="IncrementalValuesProvider{TValues}"/> instance with the gathered data.</returns>
+    protected abstract IncrementalValuesProvider<(INamedTypeSymbol Symbol, TInfo Info)> GetInfo(
+        IncrementalGeneratorInitializationContext context,
+        IncrementalValuesProvider<(INamedTypeSymbol Symbol, AttributeData AttributeData)> source);
 
     /// <summary>
     /// Validates a target type being processed.

CommunityToolkit.Mvvm.SourceGenerators/EmbeddedResources/ObservableRecipient.cs

@@ -42,6 +42,13 @@ public abstract class ObservableRecipient
     public bool IsActive
     {
         get => this.isActive;
+
+        [global::System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode(
+            "When this property is set to true, the OnActivated() method will be invoked, which will register all necessary message handlers for this recipient. " +
+            "This method requires the generated CommunityToolkit.Mvvm.Messaging.__Internals.__IMessengerExtensions type not to be removed to use the fast path. " +
+            "If this type is removed by the linker, or if the target recipient was created dynamically and was missed by the source generator, a slower fallback " +
+            "path using a compiled LINQ expression will be used. This will have more overhead in the first invocation of this method for any given recipient type. " +
+            "Alternatively, OnActivated() can be manually overwritten, and registration can be done individually for each required message for this recipient.")]
         set
         {
             if (SetProperty(ref this.isActive, value, true))
@@ -69,6 +76,11 @@ public abstract class ObservableRecipient
     /// If you need more fine tuned control, want to register messages individually or just prefer
     /// the lambda-style syntax for message registration, override this method and register manually.
     /// </remarks>
+    [global::System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode(
+        "This method requires the generated CommunityToolkit.Mvvm.Messaging.__Internals.__IMessengerExtensions type not to be removed to use the fast path. " +
+        "If this type is removed by the linker, or if the target recipient was created dynamically and was missed by the source generator, a slower fallback " +
+        "path using a compiled LINQ expression will be used. This will have more overhead in the first invocation of this method for any given recipient type. " +
+        "Alternatively, OnActivated() can be manually overwritten, and registration can be done individually for each required message for this recipient.")]
     protected virtual void OnActivated()
     {
         global::CommunityToolkit.Mvvm.Messaging.IMessengerExtensions.RegisterAll(Messenger, this);