Adjusted Memento to generate the memento child class when missing (wa…

…s not possible before Metalama 2024.2)

Fixed and adjusted tests
Added a unit test case for when we have an autogenerated memento child class that the user is trying to use in a MementoCreateHook or MementoRestoreHook

Moyou.Aspects/Moyou.Aspects.Memento/MementoAttribute.cs

@@ -5,6 +5,9 @@
 using System.Collections.Frozen;
 using System.Collections.Immutable;
 using System.Collections.ObjectModel;
+using System.Diagnostics;
+using Metalama.Framework.Advising;
+using Metalama.Framework.Code.DeclarationBuilders;
 using Moyou.Diagnostics;
 using Moyou.Extensions;
 
@@ -41,6 +44,19 @@ public class MementoAttribute : TypeAspect
                 Warnings.Memento.NonSupportedMemberInStrictModeMessageFormat,
                 Warnings.Memento.NonSupportedMemberInStrictModeTitle,
                 Warnings.Memento.NonSupportedMemberInStrictModeCategory);
+
+    /// <summary>
+    /// MOYOU1002
+    /// </summary>
+    /// <remarks>
+    /// INamedType should be target originator type
+    /// </remarks>
+    private static readonly DiagnosticDefinition<INamedType>
+        WarningNoMementoNestedClass =
+            new(Warnings.Memento.NoMementoNestedClassId, Severity.Warning,
+                Warnings.Memento.NoMementoNestedClassMessageFormat,
+                Warnings.Memento.NoMementoNestedClassTitle,
+                Warnings.Memento.NoMementoNestedClassCategory);
 
     public override void BuildAspect(IAspectBuilder<INamedType> builder)
     {
@@ -63,7 +79,14 @@ public override void BuildAspect(IAspectBuilder<INamedType> builder)
             relevantMembers = relevantMembers.Except(membersWithUnsupportedTypes).ToList();
         }
 
-        var nestedMementoType = builder.Target.NestedTypes.First(NestedTypeIsEligible);
+        var res = builder.Advice.IntroduceClass(builder.Target, "Memento", OverrideStrategy.Ignore);
+        if (res.Outcome == AdviceOutcome.Default)
+        {
+            builder.Diagnostics.Report(WarningNoMementoNestedClass.WithArguments(builder.Target), builder.Target);
+        }
+        var nestedMementoType = res.Outcome == AdviceOutcome.Default
+            ? res.Declaration
+            : builder.Target.NestedTypes.First(NestedTypeIsEligible);
 
         //introduce relevant fields and properties to the memento type
         var introducedFieldsOnMemento = IntroduceMementoTypeFields().ToList();
@@ -145,9 +168,9 @@ bool IsTypeOfMemberSupported(IFieldOrProperty member)
     public override void BuildEligibility(IEligibilityBuilder<INamedType> builder)
     {
         base.BuildEligibility(builder);
-        builder.MustSatisfy(type => type.NestedTypes.Any(NestedTypeIsEligible),
-            type =>
-                $"{type.Description} must contain a nested private class, (struct) record or struct called 'Memento''");
+        // builder.MustSatisfy(type => type.NestedTypes.Any(NestedTypeIsEligible),
+        //     type =>
+        //         $"{type.Description} must contain a nested private class, (struct) record or struct called 'Memento''");
         builder.MustNotBeAbstract();
         builder.MustNotBeInterface();
     }

Moyou.Diagnostics/Warnings.cs

@@ -27,6 +27,12 @@ public static class Memento
 
         public static string NonSupportedMemberInStrictModeTitle => "Non-supported member in strict mode";
         public static string NonSupportedMemberInStrictModeCategory => "Memento";
+
+        public static string NoMementoNestedClassId => "MOYOU1002";
+        public static string NoMementoNestedClassMessageFormat =>
+            "Class {0} does not have a nested class named Memento. One will be automatically generated. Please note that if you plan on using MementoCreateHook and MementoRestoreHook attributes, you need to either define the nested class yourself or use a fully qualified name (e.g. {0}.Memento) in the signature of your hook methods.";
+        public static string NoMementoNestedClassTitle => "Autogenerated Memento nested class";
+        public static string NoMementoNestedClassCategory => "Memento";
     }
 
     /// <summary>

Moyou.Extensions/MementoExtensions.cs

@@ -1,4 +1,5 @@
-using Metalama.Framework.Aspects;
+using System.Diagnostics;
+using Metalama.Framework.Aspects;
 using Metalama.Framework.Code;
 using Metalama.Framework.Eligibility;
 
@@ -13,15 +14,15 @@ public static void HasExactlyOneParameterOfTypeNestedMemento(this IEligibilityBu
         builder.MustSatisfyAll(innerBuilder =>
         {
             innerBuilder.MustSatisfy(method => method.Parameters.Count == 1,
-                method => $"{method.Description} must have exactly one parameter");
+                method => $"{method.Description} must have exactly one parameter of the Memento type");
             innerBuilder.MustSatisfy(method =>
             {
-                var mementoType = method.DeclaringType.NestedTypes.FirstOrDefault(type => type.Name == "Memento");
-                return mementoType != null && method.Parameters[0].Type.Is(mementoType);
+                var parameterType = (INamedType)method.Parameters[0].Type;
+                return parameterType.Name.Split('.').Last() == "Memento" && parameterType.DeclaringType == method.DeclaringType;
             }, method =>
             {
                 var mementoType =
-                    method.Object.DeclaringType.NestedTypes.FirstOrDefault(type => type.Name == "Memento");
+                    method.Object.DeclaringType.Types.FirstOrDefault(type => type.Name == "Memento");
                 return $"{method.Description} must have exactly one parameter of type {mementoType?.FullName}";
             });
         });

Moyou.Test/Memento/CreateHookAttributeTests/HasNoParameters.t.cs

@@ -1 +1 @@
-// Error LAMA0037 on `MementoCreateHook`: `The aspect 'MementoCreateHook' cannot be applied to the method 'HasNoParameters.CreateMementoHook()' because 'HasNoParameters.CreateMementoHook()' must have exactly one parameter.`
+// Error LAMA0037 on `MementoCreateHook`: `The aspect 'MementoCreateHook' cannot be applied to the method 'HasNoParameters.CreateMementoHook()' because 'HasNoParameters.CreateMementoHook()' must have exactly one parameter of the Memento type.`

Moyou.Test/Memento/CreateHookAttributeTests/HasTooManyParameters.t.cs

@@ -1 +1 @@
-// Error LAMA0037 on `MementoCreateHook`: `The aspect 'MementoCreateHook' cannot be applied to the method 'HasTooManyParameters.CreateMementoHook(int, int)' because 'HasTooManyParameters.CreateMementoHook(int, int)' must have exactly one parameter.`
+// Error LAMA0037 on `MementoCreateHook`: `The aspect 'MementoCreateHook' cannot be applied to the method 'HasTooManyParameters.CreateMementoHook(int, int)' because 'HasTooManyParameters.CreateMementoHook(int, int)' must have exactly one parameter of the Memento type.`

Moyou.Test/Memento/MementoAttributeTests/NoMementoNestedClass.t.cs

@@ -1 +1,38 @@
-// Error LAMA0037 on `Memento`: `The aspect 'Memento' cannot be applied to the type 'NoMementoNestedClass' because 'NoMementoNestedClass' must contain a nested private class, (struct) record or struct called 'Memento''.`
+// Warning MOYOU1002 on `NoMementoNestedClass`: `Class NoMementoNestedClass does not have a nested class named Memento. One will be automatically generated. Please note that if you plan on using MementoCreateHook and MementoRestoreHook attributes, you need to either define the nested class yourself or use a fully qualified name (e.g. NoMementoNestedClass.Memento) in the signature of your hook methods.`
+using Moyou.Aspects.Memento;
+namespace Moyou.CompileTimeTest.MementoTests.MementoAttributeTests;
+[Memento]
+internal class NoMementoNestedClass : global::Moyou.Aspects.Memento.IOriginator
+{
+  string A { get; set; }
+  public global::Moyou.Aspects.Memento.IMemento CreateMemento()
+  {
+    return (global::Moyou.Aspects.Memento.IMemento)this.CreateMementoImpl();
+  }
+  private global::Moyou.Aspects.Memento.IMemento CreateMementoImpl()
+  {
+    var memento = new global::Moyou.CompileTimeTest.MementoTests.MementoAttributeTests.NoMementoNestedClass.Memento();
+    memento.A = this.A;
+    return (global::Moyou.Aspects.Memento.IMemento)memento;
+  }
+  public void RestoreMemento(global::Moyou.Aspects.Memento.IMemento memento)
+  {
+    this.RestoreMementoImpl(memento);
+  }
+  private void RestoreMementoImpl(global::Moyou.Aspects.Memento.IMemento memento)
+  {
+    try
+    {
+      var cast = ((global::Moyou.CompileTimeTest.MementoTests.MementoAttributeTests.NoMementoNestedClass.Memento)memento);
+      this.A = ((global::Moyou.CompileTimeTest.MementoTests.MementoAttributeTests.NoMementoNestedClass.Memento)cast!).A;
+    }
+    catch (global::System.InvalidCastException icex)
+    {
+      throw new global::System.ArgumentException("Incorrect memento type", nameof(memento), icex);
+    }
+  }
+  class Memento : global::Moyou.Aspects.Memento.IMemento
+  {
+    public global::System.String A;
+  }
+}

Moyou.Test/Memento/RestoreHookAttributeTests/HasNoParameters.cs

@@ -5,4 +5,13 @@ namespace Moyou.CompileTimeTest.MementoTests.RestoreHookAttributeTests;
 [Memento]
 internal class HasNoParameters
 {
+    [MementoRestoreHook]
+    public void RestoreMementoHook()
+    {
+    }
+
+    private record Memento
+    {
+
+    }
 }

Moyou.Test/Memento/RestoreHookAttributeTests/HasNoParameters.t.cs

@@ -1 +1 @@
-// Error LAMA0037 on `Memento`: `The aspect 'Memento' cannot be applied to the type 'HasNoParameters' because 'HasNoParameters' must contain a nested private class, (struct) record or struct called 'Memento''.`
+// Error LAMA0037 on `MementoRestoreHook`: `The aspect 'MementoRestoreHook' cannot be applied to the method 'HasNoParameters.RestoreMementoHook()' because 'HasNoParameters.RestoreMementoHook()' must have exactly one parameter of the Memento type.`

Moyou.Test/Memento/RestoreHookAttributeTests/HasParameterOfWrongType.cs

@@ -4,8 +4,8 @@ namespace Moyou.CompileTimeTest.MementoTests.RestoreHookAttributeTests;
 [Memento]
 internal class HasParameterOfWrongType
 {
-    [MementoCreateHook]
-    public void CreateMementoHook(int parameter)
+    [MementoRestoreHook]
+    public void RestoreMementoHook(int parameter)
     {
     }
 

Moyou.Test/Memento/RestoreHookAttributeTests/HasParameterOfWrongType.t.cs

@@ -1 +1 @@
-// Error LAMA0037 on `MementoCreateHook`: `The aspect 'MementoCreateHook' cannot be applied to the method 'HasParameterOfWrongType.CreateMementoHook(int)' because 'HasParameterOfWrongType.CreateMementoHook(int)' must have exactly one parameter of type Moyou.CompileTimeTest.MementoTests.RestoreHookAttributeTests.HasParameterOfWrongType.Memento.`
+// Error LAMA0037 on `MementoRestoreHook`: `The aspect 'MementoRestoreHook' cannot be applied to the method 'HasParameterOfWrongType.RestoreMementoHook(int)' because 'HasParameterOfWrongType.RestoreMementoHook(int)' must have exactly one parameter of type Moyou.CompileTimeTest.MementoTests.RestoreHookAttributeTests.HasParameterOfWrongType.Memento.`

Moyou.Test/Memento/RestoreHookAttributeTests/HasTooManyParameters.t.cs

@@ -1 +1 @@
-// Error LAMA0037 on `MementoRestoreHook`: `The aspect 'MementoRestoreHook' cannot be applied to the method 'HasTooManyParameters.RestoreMementoHook(int, int, int)' because 'HasTooManyParameters.RestoreMementoHook(int, int, int)' must have exactly one parameter.`
+// Error LAMA0037 on `MementoRestoreHook`: `The aspect 'MementoRestoreHook' cannot be applied to the method 'HasTooManyParameters.RestoreMementoHook(int, int, int)' because 'HasTooManyParameters.RestoreMementoHook(int, int, int)' must have exactly one parameter of the Memento type.`