implement reference comparer, improve tests

src/Equatable.SourceGenerator/EquatableGenerator.cs

@@ -1,3 +1,4 @@
+using System.Reflection;
 using System.Xml.Linq;
 
 using Equatable.SourceGenerator.Models;
@@ -200,11 +201,15 @@ private static (ComparerTypes? comparerType, string? comparerName, string? compa
 
     private static (ComparerTypes? comparerType, string? comparerName, string? comparerInstance) GetStringComparer(AttributeData? attribute)
     {
-        var argument = attribute?.ConstructorArguments.FirstOrDefault();
-        if (argument == null || !argument.HasValue)
+        if (attribute == null || attribute.ConstructorArguments.Length != 1)
+            return (ComparerTypes.Default, null, null);
+
+        var argument = attribute.ConstructorArguments[0];
+
+        if (argument.Value is not int value)
             return (ComparerTypes.String, "CurrentCulture", null);
 
-        var comparerName = argument?.Value switch
+        var comparerName = value switch
         {
             0 => "CurrentCulture",
             1 => "CurrentCultureIgnoreCase",
@@ -220,30 +225,19 @@ private static (ComparerTypes? comparerType, string? comparerName, string? compa
 
     private static (ComparerTypes? comparerType, string? comparerName, string? comparerInstance) GetEqualityComparer(AttributeData? attribute)
     {
-        if (attribute == null)
+        if (attribute == null || attribute.ConstructorArguments.Length != 2)
             return (ComparerTypes.Default, null, null);
 
-        // attribute constructor
-        var comparerType = attribute.ConstructorArguments.FirstOrDefault();
-        if (comparerType.Value is INamedTypeSymbol typeSymbol)
-        {
-            return (ComparerTypes.Custom, typeSymbol.ToDisplayString(), null);
-        }
-
-        // generic attribute
-        var attributeClass = attribute.AttributeClass;
-        if (attributeClass is { IsGenericType: true }
-            && attributeClass.TypeArguments.Length == attributeClass.TypeParameters.Length
-            && attributeClass.TypeArguments.Length == 1)
-        {
-            var typeArgument = attributeClass.TypeArguments[0];
-            var comparerName = typeArgument.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+        var comparerArgument = attribute.ConstructorArguments[0];
+        if (comparerArgument.Value is not INamedTypeSymbol typeSymbol)
+            return (ComparerTypes.Default, null, null); // invalid syntax found
 
-            return (ComparerTypes.Custom, comparerName, null);
-        }
+        var comparerName = typeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
 
+        var instanceArgument = attribute.ConstructorArguments[1];
+        var comparerInstance = instanceArgument.Value as string;
 
-        return (ComparerTypes.Default, null, null);
+        return (ComparerTypes.Custom, comparerName, comparerInstance);
     }
 
 

src/Equatable.SourceGenerator/EquatableWriter.cs

@@ -124,6 +124,13 @@ private static void GenerateEquatable(IndentedStringBuilder codeBuilder, Equatab
 
                     break;
                 case ComparerTypes.Reference:
+                    codeBuilder
+                        .Append(" global::System.Object.ReferenceEquals(")
+                        .Append(entityProperty.PropertyName)
+                        .Append(", other.")
+                        .Append(entityProperty.PropertyName)
+                        .Append(")");
+
                     break;
                 case ComparerTypes.Sequence:
                     codeBuilder
@@ -395,6 +402,11 @@ private static void GenerateHashCode(IndentedStringBuilder codeBuilder, Equatabl
                         .AppendLine(");");
                     break;
                 case ComparerTypes.Reference:
+                    codeBuilder
+                        .Append("hashCode = (hashCode * -1521134295) + ")
+                        .Append("global::System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode(")
+                        .Append(entityProperty.PropertyName)
+                        .AppendLine("!);");
                     break;
                 case ComparerTypes.Sequence:
                     codeBuilder

test/Equatable.Entities/Audit.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 
 using Equatable.Attributes;
 
@@ -13,4 +12,7 @@ public partial class Audit : ModelBase
     public int? TaskId { get; set; }
     public string? Content { get; set; }
     public string? UserName { get; set; }
+
+    [ReferenceEquality]
+    public object? Lock { get; set; }
 }

test/Equatable.Entities/CustomLength.cs

@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+
+using Equatable.Attributes;
+
+namespace Equatable.Entities;
+
+[Equatable]
+public partial class CustomLength
+{
+    public int Id { get; set; }
+
+    public string Name { get; set; } = null!;
+
+    [EqualityComparer(typeof(LengthComparerDefault))]
+    public string? Key { get; set; }
+
+    [EqualityComparer(typeof(LengthComparerInstance), nameof(LengthComparerInstance.Instance))]
+    public string? Value { get; set; }
+
+}
+
+public static class LengthComparerDefault
+{
+    public static readonly LengthEqualityComparer Default = new();
+}
+
+public static class LengthComparerInstance
+{
+    public static readonly LengthEqualityComparer Instance = new();
+}
+
+public class LengthEqualityComparer : IEqualityComparer<string?>
+{
+    public bool Equals(string? x, string? y) => x?.Length == y?.Length;
+
+    public int GetHashCode(string? obj) => obj?.Length.GetHashCode() ?? 0;
+}
+

test/Equatable.Entities/Equatable.Entities.csproj

@@ -8,6 +8,10 @@
     <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="System.Text.Json" Version="8.0.4" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\..\src\Equatable.Generator\Equatable.Generator.csproj" />
     <ProjectReference Include="..\..\src\Equatable.SourceGenerator\Equatable.SourceGenerator.csproj">

test/Equatable.Entities/Nested.cs

@@ -2,13 +2,13 @@
 
 namespace Equatable.Entities;
 
-public class Nested
+public partial class Nested
 {
     //[Equatable]
     public partial class Animal
     {
         public int Id { get; set; }
-        public string Name { get; set; }
-        public string Type { get; set; }
+        public string? Name { get; set; }
+        public string? Type { get; set; }
     }
 }

test/Equatable.Entities/UserImport.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
 using Equatable.Attributes;
 
 namespace Equatable.Entities;
@@ -10,6 +12,7 @@ public partial class UserImport
     [StringEquality(StringComparison.OrdinalIgnoreCase)]
     public string EmailAddress { get; set; } = null!;
 
+    [JsonPropertyName("name")]
     public string? DisplayName { get; set; }
 
     public string? FirstName { get; set; }
@@ -20,6 +23,7 @@ public partial class UserImport
 
     public DateTimeOffset? LastLogin { get; set; }
 
+    [JsonIgnore]
     [IgnoreEquality]
     public string FullName => $"{FirstName} {LastName}";
 

test/Equatable.Generator.Tests/Entities/AuditTest.cs

@@ -0,0 +1,122 @@
+using Equatable.Entities;
+
+namespace Equatable.Generator.Tests.Entities;
+
+public class AuditTest
+{
+    [Fact]
+    public void EqualAuditTrue()
+    {
+        var lockObject = new object();
+
+        var left = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = lockObject
+        };
+
+        var right = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = lockObject
+        };
+
+        var isEqual = left.Equals(right);
+        isEqual.Should().BeTrue();
+
+        // check operator ==
+        isEqual = left == right;
+        isEqual.Should().BeTrue();
+    }
+
+    [Fact]
+    public void NotEqualAudit()
+    {
+        var left = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = new object()
+        };
+
+        var right = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = new object()
+        };
+
+        var isEqual = left.Equals(right);
+        isEqual.Should().BeFalse();
+
+        // check operator !=
+        isEqual = left != right;
+        isEqual.Should().BeTrue();
+
+    }
+
+    [Fact]
+    public void HashCodeAuditTrue()
+    {
+        var lockObject = new object();
+        var left = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = lockObject
+        };
+
+        var right = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = lockObject
+        };
+
+        var leftCode = left.GetHashCode();
+        var rightCode = right.GetHashCode();
+
+        leftCode.Should().Be(rightCode);
+    }
+
+    [Fact]
+    public void HashCodeAuditNotEqual()
+    {
+        var left = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = new object()
+        };
+
+        var right = new Audit
+        {
+            Id = 1,
+            Date = new DateTime(2024, 9, 1),
+            UserId = 1,
+            TaskId = 2,
+            Lock = new object()
+        };
+
+        var leftCode = left.GetHashCode();
+        var rightCode = right.GetHashCode();
+
+        leftCode.Should().NotBe(rightCode);
+    }
+}