Merge pull request #236 from CommunityToolkit/dev/observable-validator-partial-declarations

Fix ObservableValidator duplicate generated partial declarations

Author: Sergio0694

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableObjectGenerator.cs

@@ -7,7 +7,6 @@
 using CommunityToolkit.Mvvm.SourceGenerators.Diagnostics;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.cs

@@ -5,14 +5,12 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.ComponentModel.Models;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/ObservableValidatorValidateAllPropertiesGenerator.cs

@@ -3,13 +3,11 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;
 
@@ -27,7 +25,9 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             context.SyntaxProvider
             .CreateSyntaxProvider(
                 static (node, _) => node is ClassDeclarationSyntax,
-                static (context, _) => (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!);
+                static (context, _) => (context.Node, Symbol: (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!))
+            .Where(static item => item.Node.IsFirstSyntaxDeclarationForSymbol(item.Symbol))
+            .Select(static (item, _) => item.Symbol);
 
         // Get the types that inherit from ObservableValidator and gather their info
         IncrementalValuesProvider<ValidationInfo> validationInfo =

CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/TransitiveMembersGenerator.cs

@@ -5,14 +5,11 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
-using CommunityToolkit.Mvvm.SourceGenerators.Diagnostics;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;

CommunityToolkit.Mvvm.SourceGenerators/Extensions/SyntaxNodeExtensions.cs

@@ -0,0 +1,34 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.CodeAnalysis;
+
+namespace CommunityToolkit.Mvvm.SourceGenerators.Extensions;
+
+/// <summary>
+/// Extension methods for the <see cref="SyntaxNode"/> type.
+/// </summary>
+internal static class SyntaxNodeExtensions
+{
+    /// <summary>
+    /// Checks whether a given <see cref="SyntaxNode"/> represents the first (partial) declaration of a given symbol.
+    /// </summary>
+    /// <param name="syntaxNode">The input <see cref="SyntaxNode"/> instance.</param>
+    /// <param name="symbol">The target <see cref="ISymbol"/> instance to check the syntax declaration for.</param>
+    /// <returns>Whether <paramref name="syntaxNode"/> is the first (partial) declaration for <paramref name="symbol"/>.</returns>
+    /// <remarks>
+    /// This extension can be used to avoid accidentally generating repeated members for types that have multiple partial declarations.
+    /// In order to keep this check efficient and without the need to collect all items and build some sort of hashset from them to
+    /// remove duplicates, each syntax node is symply compared against the available declaring syntax references for the target symbol.
+    /// If the syntax node matches the first syntax reference for the symbol, it is kept, otherwise it is considered a duplicate.
+    /// </remarks>
+    public static bool IsFirstSyntaxDeclarationForSymbol(this SyntaxNode syntaxNode, ISymbol symbol)
+    {
+        return
+            symbol.DeclaringSyntaxReferences.Length > 0 &&
+            symbol.DeclaringSyntaxReferences[0] is SyntaxReference syntaxReference &&
+            syntaxReference.SyntaxTree == syntaxNode.SyntaxTree &&
+            syntaxReference.Span == syntaxNode.Span;
+    }
+}

CommunityToolkit.Mvvm.SourceGenerators/Input/ICommandGenerator.cs

@@ -4,15 +4,12 @@
 
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
-using CommunityToolkit.Mvvm.SourceGenerators.Diagnostics;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
 using CommunityToolkit.Mvvm.SourceGenerators.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;

CommunityToolkit.Mvvm.SourceGenerators/Messaging/IMessengerRegisterAllGenerator.cs

@@ -4,13 +4,11 @@
 
 using System.Collections.Immutable;
 using System.Linq;
-using System.Text;
 using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
 using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 
 namespace CommunityToolkit.Mvvm.SourceGenerators;
 
@@ -32,11 +30,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
             .CreateSyntaxProvider(
                 static (node, _) => node is ClassDeclarationSyntax,
                 static (context, _) => (context.Node, Symbol: (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!))
-            .Where(static item =>
-                item.Symbol.DeclaringSyntaxReferences.Length > 0 &&
-                item.Symbol.DeclaringSyntaxReferences[0] is SyntaxReference syntaxReference &&
-                syntaxReference.SyntaxTree == item.Node.SyntaxTree &&
-                syntaxReference.Span == item.Node.Span)
+            .Where(static item => item.Node.IsFirstSyntaxDeclarationForSymbol(item.Symbol))
             .Select(static (item, _) => item.Symbol);
 
         // Get the target IRecipient<TMessage> interfaces and filter out other types

tests/CommunityToolkit.Mvvm.UnitTests/Test_ObservableValidator.cs

@@ -382,6 +382,36 @@ public void Test_ObservableValidator_ValidateAllProperties_WithFallback()
         Assert.IsTrue(events.Any(e => e.PropertyName == nameof(Person.Age)));
     }
 
+    // See https://github.com/CommunityToolkit/dotnet/issues/235
+    [TestMethod]
+    public void Test_ObservableValidator_ValidateAllProperties_WithinPartialClassDeclaration()
+    {
+        PersonWithPartialDeclaration model = new();
+        List<DataErrorsChangedEventArgs> events = new();
+
+        model.ErrorsChanged += (s, e) => events.Add(e);
+
+        model.ValidateAllProperties();
+
+        Assert.IsTrue(model.HasErrors);
+        Assert.IsTrue(events.Count == 2);
+
+        Assert.IsTrue(events.Any(e => e.PropertyName == nameof(PersonWithPartialDeclaration.Name)));
+        Assert.IsTrue(events.Any(e => e.PropertyName == nameof(PersonWithPartialDeclaration.Number)));
+
+        events.Clear();
+
+        model.Name = "Bob";
+        model.Number = 42;
+
+        model.ValidateAllProperties();
+
+        Assert.IsFalse(model.HasErrors);
+        Assert.IsTrue(events.Count == 2);
+        Assert.IsTrue(events.Any(e => e.PropertyName == nameof(PersonWithPartialDeclaration.Name)));
+        Assert.IsTrue(events.Any(e => e.PropertyName == nameof(PersonWithPartialDeclaration.Number)));
+    }
+
     [TestMethod]
     public void Test_ObservableValidator_CustomValidation()
     {
@@ -729,4 +759,22 @@ public class ObservableValidatorDerived : ObservableValidatorBase
 
         public int SomeRandomproperty { get; set; }
     }
+
+    public partial class PersonWithPartialDeclaration : ObservableValidator
+    {
+        [Required]
+        [MinLength(1)]
+        public string? Name { get; set; }
+
+        public new void ValidateAllProperties()
+        {
+            base.ValidateAllProperties();
+        }
+    }
+
+    public partial class PersonWithPartialDeclaration
+    {
+        [Range(10, 1000)]
+        public int Number { get; set; }
+    }
 }