Merge pull request #186 from SteveDunn/allow-override-tostring

Allow user to supply their own ToString

src/Vogen/BuildWorkItems.cs

@@ -55,6 +55,8 @@ internal static class BuildWorkItems
         ReportErrorIfNestedType(target, context, voSymbolInformation);
 
         var instanceProperties = TryBuildInstanceProperties(attributes, voSymbolInformation, context);
+
+        var hasToString = HasToStringOverload(voSymbolInformation);
 
         MethodDeclarationSyntax? validateMethod = null;
         MethodDeclarationSyntax? normalizeInputMethod = null;
@@ -89,6 +91,7 @@ internal static class BuildWorkItems
             InstanceProperties = instanceProperties.ToList(),
             TypeToAugment = voTypeSyntax,
             IsValueType = isValueType,
+            HasToString = hasToString,
             UnderlyingType = config.UnderlyingType,
             Conversions = config.Conversions,
             Customizations = config.Customizations,
@@ -99,6 +102,50 @@ internal static class BuildWorkItems
         };
     }
 
+    private static bool HasToStringOverload(ITypeSymbol typeSymbol)
+    {
+        while (true)
+        {
+            var toStringMethods = typeSymbol.GetMembers("ToString").OfType<IMethodSymbol>();
+
+            foreach (IMethodSymbol eachMethod in toStringMethods)
+            {
+                // we could have "public virtual new string ToString() => "xxx" 
+                if (!eachMethod.IsOverride && !eachMethod.IsVirtual)
+                {
+                    continue;
+                }
+
+                // can't change access rights
+                if (eachMethod.DeclaredAccessibility != Accessibility.Public && eachMethod.DeclaredAccessibility != Accessibility.Protected)
+                {
+                    continue;
+                }
+
+                if (eachMethod.Parameters.Length != 0)
+                {
+                    continue;
+                }
+
+                return true;
+            }
+
+            INamedTypeSymbol? baseType = typeSymbol.BaseType;
+
+            if (baseType is null)
+            {
+                return false;
+            }
+
+            if (baseType.SpecialType == SpecialType.System_Object)
+            {
+                return false;
+            }
+
+            typeSymbol = baseType;
+        }
+    }
+
     private static bool IsUnderlyingAValueType(VogenConfiguration config)
     {
         bool isValueType = true;

src/Vogen/Generators/ClassGenerator.cs

@@ -151,7 +151,7 @@ private void EnsureInitialized()
 
         {Util.GenerateAnyInstances(tds, item)}
 
-        public override global::System.String ToString() => Value.ToString();
+        {Util.GenerateToString(item)}
 
         {Util.GenerateAnyConversionBodies(tds, item)}
 

src/Vogen/Util.cs

@@ -233,4 +233,7 @@ public static string GenerateDebuggerProxyForClasses(TypeDeclarationSyntax tds,
 
     public static string GenerateYourAssemblyName() => typeof(Util).Assembly.GetName().Name;
     public static string GenerateYourAssemblyVersion() => typeof(Util).Assembly.GetName().Version.ToString();
+
+    public static string GenerateToString(VoWorkItem item) => 
+        item.HasToString ? string.Empty : "public override global::System.String ToString() => Value.ToString();";
 }

src/Vogen/VoWorkItem.cs

@@ -34,4 +34,6 @@ public class VoWorkItem
     public string VoTypeName => TypeToAugment.Identifier.ToString();
 
     public string UnderlyingTypeFullName => UnderlyingType.FullName() ?? UnderlyingType?.Name ?? "global::System.Int32";
+
+    public bool HasToString { get; set; } = false;
 }

tests/SmallTests/ToStringTests.cs

@@ -1,14 +1,44 @@
 using FluentAssertions;
+using Vogen;
 using Vogen.Tests.Types;
 using Xunit;
 
-namespace Vogen.Tests;
+namespace SmallTests;
+
+public class ToString_Derived1
+{
+    public override string ToString() => "derived1!";
+}
+
+public class ToString_Derived2 : ToString_Derived1
+{
+    public new virtual string ToString() => "derived2!";
+}
+
+public class ToString_Derived3 : ToString_Derived2
+{
+}
+
+[ValueObject]
+public partial class ToString_Vo
+{
+    public override string ToString() => "ToString_Vo!";
+}
+
+[ValueObject]
+public partial class ToString_Vo_Derived1 : ToString_Derived1
+{
+}
+
+[ValueObject]
+public partial class ToString_Vo_Derived2 : ToString_Derived3
+{
+}
 
 public class ToStringTests
 {
-
     [Fact]
-    public void To_string()
+    public void ToString_uses_generated_method()
     {
         Age.From(18).ToString().Should().Be("18");
         Age.From(100).ToString().Should().Be("100");
@@ -18,4 +48,16 @@ public void To_string()
         Name.From("barney").ToString().Should().Be("barney");
         Name.From("wilma").ToString().Should().Be("wilma");
     }
+
+    [Fact]
+    public void ToString_uses_users_method() => 
+        ToString_Vo.From(18).ToString().Should().Be("ToString_Vo!");
+
+    [Fact]
+    public void ToString_uses_derived_method() => 
+        ToString_Vo_Derived1.From(18).ToString().Should().Be("derived1!");
+
+    [Fact]
+    public void ToString_uses_least_derived_method() => 
+        ToString_Vo_Derived2.From(18).ToString().Should().Be("derived2!");
 }

tests/Testbench/Program.cs

@@ -7,22 +7,12 @@ public class Program
     {
         public static void Main()
         {
-            GeneratedValueObject c = Create(new Object[]
-            {
-                new()
-            });
-        }
-
-        static GeneratedValueObject Create(Object[] normalObject)
-        {
-            return null!;//GeneratedValueObject.From(10);
+            // To debug the source generator or analyzer, set the active project to Vogen,
+            // and then select Roslyn as the debug target. This requires the Roslyn SDK
+            // to be installed in the list of Visual Studio components.
         }
     }
-
-    [ValueObject]
-    partial class GeneratedValueObject {    }
-
-    public abstract partial record class x(string X){}
 }
 
 
+