Fix duplicate generated files for ObservableValidator generator

Author: Sergio0694

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 =

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; }
+    }
 }