- fix passed null in factories

- fix ctors without params not checking for remaining args

LightweightIocContainer.Validation/IocValidator.cs

@@ -96,7 +96,7 @@ public class IocValidator
         }
         catch (Exception)
         {
-            return null; 
+            return new NullParameter(type); 
         }
     }
 }

LightweightIocContainer/Factories/FactoryHelper.cs

@@ -0,0 +1,35 @@
+// Author: Gockner, Simon
+// Created: 2022-09-02
+// Copyright(c) 2022 SimonG. All Rights Reserved.
+
+using System.Reflection;
+
+namespace LightweightIocContainer.Factories;
+
+/// <summary>
+/// Helper class for the <see cref="TypedFactory{TFactory}"/>
+/// </summary>
+public class FactoryHelper
+{
+    /// <summary>
+    /// Convert `null` passed as argument to <see cref="NullParameter"/> to handle it correctly
+    /// </summary>
+    /// <param name="createMethod">The create method of the factory</param>
+    /// <param name="arguments">The arguments passed to the create method</param>
+    /// <returns>List of arguments with converted null</returns>
+    /// <exception cref="Exception">Wrong parameters passed</exception>
+    public object?[] ConvertPassedNull(MethodBase createMethod, params object?[] arguments)
+    {
+        if (!arguments.Any())
+            return arguments;
+
+        ParameterInfo[] parameters = createMethod.GetParameters();
+        if (arguments.Length != parameters.Length)
+            throw new Exception("Wrong parameters passed");
+            
+        for (int i = 0; i < arguments.Length; i++) 
+            arguments[i] ??= new NullParameter(parameters[i].ParameterType);
+
+        return arguments;
+    }
+}

LightweightIocContainer/Factories/TypedFactory.cs

@@ -44,15 +44,21 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
             
         typeBuilder.AddInterfaceImplementation(factoryType);
 
-        //add `private readonly IIocContainer _container` field
+        //add `private readonly IocContainer _container` field
         FieldBuilder containerFieldBuilder = typeBuilder.DefineField("_container", typeof(IocContainer), FieldAttributes.Private | FieldAttributes.InitOnly);
         
+        //add `private readonly FactoryHelper _helper` field
+        FieldBuilder helperFieldBuilder = typeBuilder.DefineField("_helper", typeof(FactoryHelper), FieldAttributes.Private | FieldAttributes.InitOnly);
+
         //add ctor
-        ConstructorBuilder constructorBuilder = typeBuilder.DefineConstructor(MethodAttributes.Public, CallingConventions.HasThis, new[] {typeof(IocContainer)});
+        ConstructorBuilder constructorBuilder = typeBuilder.DefineConstructor(MethodAttributes.Public, CallingConventions.HasThis, new[] {typeof(IocContainer), typeof(FactoryHelper)});
         ILGenerator constructorGenerator = constructorBuilder.GetILGenerator();
         constructorGenerator.Emit(OpCodes.Ldarg_0);
         constructorGenerator.Emit(OpCodes.Ldarg_1);
         constructorGenerator.Emit(OpCodes.Stfld, containerFieldBuilder); //set `_container` field
+        constructorGenerator.Emit(OpCodes.Ldarg_0);
+        constructorGenerator.Emit(OpCodes.Ldarg_2);
+        constructorGenerator.Emit(OpCodes.Stfld, helperFieldBuilder); //set `_helper` field
         constructorGenerator.Emit(OpCodes.Ret);
 
         foreach (MethodInfo createMethod in CreateMethods)
@@ -60,7 +66,9 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
             //create a method that looks like this
             //public `createMethod.ReturnType` Create(`createMethod.GetParameters()`)
             //{
-            //    return IIocContainer.Resolve(`createMethod.ReturnType`, params);
+            //    createMethod = MethodBase.GetCurrentMethod();
+            //    object[] args = _helper.ConvertPassedNull(createMethod, params);
+            //    return IocContainer.Resolve(`createMethod.ReturnType`, args);
             //}
 
             ParameterInfo[] args = createMethod.GetParameters();
@@ -70,9 +78,16 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
             typeBuilder.DefineMethodOverride(methodBuilder, createMethod);
 
             ILGenerator generator = methodBuilder.GetILGenerator();
+            generator.DeclareLocal(typeof(MethodBase));
+            generator.DeclareLocal(typeof(object[]));
+
+            generator.EmitCall(OpCodes.Call, typeof(MethodBase).GetMethod(nameof(MethodBase.GetCurrentMethod))!, null);
+            generator.Emit(OpCodes.Stloc_0);
             
             generator.Emit(OpCodes.Ldarg_0);
-            generator.Emit(OpCodes.Ldfld, containerFieldBuilder);
+            generator.Emit(OpCodes.Ldfld, helperFieldBuilder);
+            
+            generator.Emit(OpCodes.Ldloc_0);
 
             if (args.Any())
             {
@@ -94,7 +109,13 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
                 generator.EmitCall(OpCodes.Call, emptyArray, null);
             }
             
-            generator.EmitCall(OpCodes.Call, typeof(IocContainer).GetMethod(nameof(IocContainer.FactoryResolve), new[] { typeof(object[]) })!.MakeGenericMethod(createMethod.ReturnType), null);
+            generator.EmitCall(OpCodes.Call, typeof(FactoryHelper).GetMethod(nameof(FactoryHelper.ConvertPassedNull), new[] { typeof(MethodBase), typeof(object?[]) })!, null);
+            generator.Emit(OpCodes.Stloc_1);
+            generator.Emit(OpCodes.Ldarg_0);
+            generator.Emit(OpCodes.Ldfld, containerFieldBuilder);
+            generator.Emit(OpCodes.Ldloc_1);
+
+            generator.EmitCall(OpCodes.Call, typeof(IocContainer).GetMethod(nameof(IocContainer.FactoryResolve), new[] { typeof(object?[]) })!.MakeGenericMethod(createMethod.ReturnType), null);
             generator.Emit(OpCodes.Castclass, createMethod.ReturnType);
             generator.Emit(OpCodes.Ret);
         }
@@ -106,7 +127,7 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
             //create a method that looks like this
             //public void ClearMultitonInstance<typeToClear>()
             //{
-            //    IIocContainer.ClearMultitonInstances<typeToClear>();
+            //    IocContainer.ClearMultitonInstances<typeToClear>();
             //}
 
             if (multitonClearMethod.IsGenericMethod)
@@ -134,6 +155,6 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
             }
         }
 
-        return Creator.CreateInstance<TFactory>(typeBuilder.CreateTypeInfo()!.AsType(), container);
+        return Creator.CreateInstance<TFactory>(typeBuilder.CreateTypeInfo()!.AsType(), container, new FactoryHelper());
     }
 }

LightweightIocContainer/IocContainer.cs

@@ -117,7 +117,7 @@ public class IocContainer : IIocContainer, IIocResolver
     /// <typeparam name="T">The given <see cref="Type"/></typeparam>
     /// <param name="arguments">The constructor arguments</param>
     /// <returns>An instance of the given <see cref="Type"/></returns>
-    public T FactoryResolve<T>(params object[] arguments) => ResolveInternal<T>(arguments, null, true);
+    public T FactoryResolve<T>(params object?[] arguments) => ResolveInternal<T>(arguments, null, true);
 
     /// <summary>
     /// Gets an instance of a given registered <see cref="Type"/>
@@ -127,7 +127,7 @@ public class IocContainer : IIocContainer, IIocResolver
     /// <param name="resolveStack">The current resolve stack</param>
     /// <param name="isFactoryResolve">True if resolve is called from factory, false (default) if not</param>
     /// <returns>An instance of the given registered <see cref="Type"/></returns>
-    private T ResolveInternal<T>(object[]? arguments, List<Type>? resolveStack = null, bool isFactoryResolve = false) => ResolveInstance<T>(TryResolve<T>(arguments, resolveStack, isFactoryResolve));
+    private T ResolveInternal<T>(object?[]? arguments, List<Type>? resolveStack = null, bool isFactoryResolve = false) => ResolveInstance<T>(TryResolve<T>(arguments, resolveStack, isFactoryResolve));
 
     /// <summary>
     /// Tries to resolve the given <see cref="Type"/> with the given arguments
@@ -484,8 +484,6 @@ public class IocContainer : IIocContainer, IIocResolver
     private (bool result, List<object?>? parameters, List<ConstructorNotMatchingException>? exceptions) TryGetConstructorResolveStack(ConstructorInfo constructor, object?[]? arguments, List<Type> resolveStack)
     {
         List<ParameterInfo> constructorParameters = constructor.GetParameters().ToList();
-        if (!constructorParameters.Any())
-            return (true, null, null);
             
         List<ConstructorNotMatchingException> exceptions = new();
         List<object?> parameters = new();
@@ -500,10 +498,15 @@ public class IocContainer : IIocContainer, IIocResolver
             if (passedArguments != null)
             {
                 fittingArgument = passedArguments.FirstOrGiven<object?, InternalResolvePlaceholder>(a =>
-                    a?.GetType() == parameter.ParameterType || parameter.ParameterType.IsInstanceOfType(a));
+                    a?.GetType() == parameter.ParameterType ||
+                    parameter.ParameterType.IsInstanceOfType(a) ||
+                    a is NullParameter nullParameter && parameter.ParameterType.IsAssignableFrom(nullParameter.ParameterType));
 
                 if (fittingArgument is not InternalResolvePlaceholder)
                     passedArguments.Remove(fittingArgument);
+                
+                if (fittingArgument is NullParameter)
+                    fittingArgument = null;
             }
 
             if (fittingArgument is InternalResolvePlaceholder)
@@ -537,7 +540,6 @@ public class IocContainer : IIocContainer, IIocResolver
         
         exceptions.Add(new ConstructorNotMatchingException(constructor, new Exception("Not all given arguments were used!")));
         return (false, parameters, exceptions);
-
     }
 
     /// <summary>

LightweightIocContainer/LightweightIocContainer.xml

@@ -356,6 +356,20 @@
             <see cref="T:LightweightIocContainer.Interfaces.Factories.ITypedFactory"/> implementation for custom implemented factories
             </summary>
         </member>
+        <member name="T:LightweightIocContainer.Factories.FactoryHelper">
+            <summary>
+            Helper class for the <see cref="T:LightweightIocContainer.Factories.TypedFactory`1"/>
+            </summary>
+        </member>
+        <member name="M:LightweightIocContainer.Factories.FactoryHelper.ConvertPassedNull(System.Reflection.MethodBase,System.Object[])">
+            <summary>
+            Convert `null` passed as argument to <see cref="T:LightweightIocContainer.NullParameter"/> to handle it correctly
+            </summary>
+            <param name="createMethod">The create method of the factory</param>
+            <param name="arguments">The arguments passed to the create method</param>
+            <returns>List of arguments with converted null</returns>
+            <exception cref="T:System.Exception">Wrong parameters passed</exception>
+        </member>
         <member name="T:LightweightIocContainer.Factories.TypedFactory`1">
             <summary>
             Class to help implement an abstract typed factory
@@ -1197,6 +1211,22 @@
             A new instance gets created if the given scope has no created instance yet. Otherwise the already created instance is used.
             </summary>
         </member>
+        <member name="T:LightweightIocContainer.NullParameter">
+            <summary>
+            Wrapper class to handle null passed as an argument correctly
+            </summary>
+        </member>
+        <member name="M:LightweightIocContainer.NullParameter.#ctor(System.Type)">
+            <summary>
+            Wrapper class to handle null passed as an argument correctly
+            </summary>
+            <param name="parameterType">The <see cref="T:System.Type"/> of the parameter</param>
+        </member>
+        <member name="P:LightweightIocContainer.NullParameter.ParameterType">
+            <summary>
+            The <see cref="T:System.Type"/> of the parameter
+            </summary>
+        </member>
         <member name="T:LightweightIocContainer.Registrations.MultipleMultitonRegistration`3">
             <summary>
             An <see cref="T:LightweightIocContainer.Interfaces.Registrations.IRegistrationBase"/> to register multiple interfaces for on implementation type that implements them as a multiton

LightweightIocContainer/NullParameter.cs

@@ -0,0 +1,22 @@
+// Author: Gockner, Simon
+// Created: 2022-09-02
+// Copyright(c) 2022 SimonG. All Rights Reserved.
+
+namespace LightweightIocContainer;
+
+/// <summary>
+/// Wrapper class to handle null passed as an argument correctly
+/// </summary>
+public class NullParameter
+{
+    /// <summary>
+    /// Wrapper class to handle null passed as an argument correctly
+    /// </summary>
+    /// <param name="parameterType">The <see cref="Type"/> of the parameter</param>
+    public NullParameter(Type parameterType) => ParameterType = parameterType;
+    
+    /// <summary>
+    /// The <see cref="Type"/> of the parameter
+    /// </summary>
+    public Type ParameterType { get; }
+}

Test.LightweightIocContainer.Validation/IocValidatorTest.cs

@@ -33,12 +33,21 @@ public class IocValidatorTest
         public Test(IParameter parameter) => parameter.Method();
     }
 
-    private class TestViewModel : ITest
+    [UsedImplicitly]
+    private class TestViewModelIgnoreDesignTimeCtor : ITest
     {
-        public TestViewModel(IParameter parameter) => parameter.Method();
+        public TestViewModelIgnoreDesignTimeCtor(IParameter parameter) => parameter.Method();
         
         [IocIgnoreConstructor]
-        public TestViewModel() => throw new Exception();
+        public TestViewModelIgnoreDesignTimeCtor() => throw new Exception();
+    }
+    
+    [UsedImplicitly]
+    private class TestViewModelDontIgnoreDesignTimeCtor : ITest
+    {
+        public TestViewModelDontIgnoreDesignTimeCtor(string name, IParameter parameter) => parameter.Method();
+        
+        public TestViewModelDontIgnoreDesignTimeCtor() => throw new Exception();
     }
 
     private class Parameter : IParameter
@@ -52,6 +61,12 @@ public class IocValidatorTest
         ITest Create(IParameter parameter);
     }
     
+    [UsedImplicitly]
+    public interface ITestMissingParamFactory
+    {
+        ITest Create(string name);
+    }
+    
     [UsedImplicitly]
     public interface IInvalidTestFactory
     {
@@ -97,11 +112,20 @@ public class IocValidatorTest
         }
     }
     
+    private class TestInstallerInvalidFactoryParameterDesignTimeCtorNotIgnoredRegisteredWithFactory : IIocInstaller
+    {
+        public void Install(IRegistrationCollector registration)
+        {
+            registration.Add<ITest, Test>().WithFactory<IInvalidTestFactory>();
+            registration.Add<IParameter, Parameter>().WithFactory<IParameterFactory>();
+        }
+    }
+    
     private class TestInstallerInvalidFactoryViewModel : IIocInstaller
     {
         public void Install(IRegistrationCollector registration)
         {
-            registration.Add<ITest, TestViewModel>().WithFactory<IInvalidTestFactory>();
+            registration.Add<ITest, TestViewModelDontIgnoreDesignTimeCtor>().WithFactory<ITestMissingParamFactory>();
             registration.Add<IParameter, Parameter>().WithFactory<IParameterFactory>();
         }
     }
@@ -212,6 +236,31 @@ public class IocValidatorTest
         Assert.IsInstanceOf<DirectResolveWithRegisteredFactoryNotAllowed>(iTest2CtorNotMatchingException.InnerExceptions[0]);
     }
     
+    [Test]
+    public void TestValidateViewModelWithInvalidParameterDesignTimeCtorNotIgnoredWithFactory()
+    {
+        IocContainer iocContainer = new();
+        iocContainer.Install(new TestInstallerInvalidFactoryParameterDesignTimeCtorNotIgnoredRegisteredWithFactory());
+            
+        IocValidator validator = new(iocContainer);
+
+        AggregateException aggregateException = Assert.Throws<AggregateException>(() => validator.Validate());
+        
+        if (aggregateException?.InnerExceptions[0] is not NoMatchingConstructorFoundException noMatchingConstructorFoundException)
+        {
+            Assert.Fail($"First element of {nameof(aggregateException.InnerExceptions)} is not of type {nameof(NoMatchingConstructorFoundException)}.");
+            return;
+        }
+            
+        if (noMatchingConstructorFoundException.InnerExceptions[0] is not ConstructorNotMatchingException iTest2CtorNotMatchingException)
+        {
+            Assert.Fail($"First element of {nameof(noMatchingConstructorFoundException.InnerExceptions)} is not of type {nameof(ConstructorNotMatchingException)}.");
+            return;
+        }
+            
+        Assert.IsInstanceOf<DirectResolveWithRegisteredFactoryNotAllowed>(iTest2CtorNotMatchingException.InnerExceptions[0]);
+    }
+        
     [Test]
     public void TestValidateInvalidFactory()
     {

Test.LightweightIocContainer/FluentFactoryRegistrationTest.cs

@@ -44,6 +44,35 @@ public class FluentFactoryRegistrationTest
         }
     }
     
+    private class TestNull : ITest
+    {
+
+        public TestNull(object obj, string content, string optional1, string optional2, ITestNullFactory testNullFactory)
+        {
+            Obj = obj;
+            Content = content;
+            Optional1 = optional1;
+            Optional2 = optional2;
+            TestNullFactory = testNullFactory;
+        }
+        
+        public object Obj { get; }
+        public string Content { get; }
+        public string Optional1 { get; }
+        public string Optional2 { get; }
+        public ITestNullFactory TestNullFactory { get; }
+    }
+        
+    public interface ITestNullFactory
+    {
+        ITest Create(object obj, string content, string optional1, string optional2);
+    }
+    
+    public interface ITestDefaultFactory
+    {
+        ITest Create(object obj, string content, string optional1, string optional2, ITestNullFactory testNullFactory = null);
+    }
+    
     private interface ITestFactoryNoCreate
     {
             
@@ -68,9 +97,9 @@ public class FluentFactoryRegistrationTest
     private class TestFactory : ITestFactory
     {
         public ITest Create() => new Test();
-        public ITest Create(string name) => throw new System.NotImplementedException();
+        public ITest Create(string name) => throw new NotImplementedException();
-        public ITest CreateTest(string name = null) => throw new System.NotImplementedException();
+        public ITest CreateTest(string name = null) => throw new NotImplementedException();
-        public ITest Create(byte id) => throw new System.NotImplementedException();
+        public ITest Create(byte id) => throw new NotImplementedException();
     }
         
     [UsedImplicitly]
@@ -211,6 +240,55 @@ public class FluentFactoryRegistrationTest
         Assert.IsInstanceOf<TestByte>(createdTest);
     }
 
+    [Test]
+    public void TestPassingNullAsMiddleParameter()
+    {
+        _iocContainer.Register(r => r.Add<ITest, TestNull>().WithFactory<ITestNullFactory>());
+
+        ITestNullFactory testNullFactory = _iocContainer.Resolve<ITestNullFactory>();
+
+        object obj = new();
+        string content = "TestContent";
+        string optional2 = "optionalParameter2";
+
+        ITest createdTest = testNullFactory.Create(obj, content, null, optional2);
+        if (createdTest is not TestNull testNull)
+        {
+            Assert.Fail();
+            return;
+        }
+        
+        Assert.AreSame(obj, testNull.Obj);
+        Assert.AreEqual(content, testNull.Content);
+        Assert.AreEqual(null, testNull.Optional1);
+        Assert.AreEqual(optional2, testNull.Optional2);
+    }
+    
+    [Test]
+    public void TestPassingNullAsDefaultParameter()
+    {
+        _iocContainer.Register(r => r.Add<ITest, TestNull>().WithFactory<ITestDefaultFactory>());
+
+        ITestDefaultFactory testDefaultFactory = _iocContainer.Resolve<ITestDefaultFactory>();
+
+        object obj = new();
+        string content = "TestContent";
+        string optional2 = "optionalParameter2";
+
+        ITest createdTest = testDefaultFactory.Create(obj, content, null, optional2);
+        if (createdTest is not TestNull testNull)
+        {
+            Assert.Fail();
+            return;
+        }
+        
+        Assert.AreSame(obj, testNull.Obj);
+        Assert.AreEqual(content, testNull.Content);
+        Assert.AreEqual(null, testNull.Optional1);
+        Assert.AreEqual(optional2, testNull.Optional2);
+        Assert.AreEqual(null, testNull.TestNullFactory);
+    }
+        
     [Test]
     public void TestResolveMultitonFromFactory()
     {