- fix bug where singletons could be created multiple times

LightweightIocContainer/IocContainer.cs

@@ -203,6 +203,10 @@ namespace LightweightIocContainer
         /// <returns>A recursively resolved instance of the given <see cref="Type"/></returns>
         private T ResolvePlaceholder<T>(InternalToBeResolvedPlaceholder toBeResolvedPlaceholder)
         {
+            object? existingInstance = TryGetExistingInstance<T>(toBeResolvedPlaceholder.ResolvedRegistration, toBeResolvedPlaceholder.Parameters);
+            if (existingInstance is T instance)
+                return instance;
+
             if (toBeResolvedPlaceholder.Parameters == null)
                 return CreateInstance<T>(toBeResolvedPlaceholder.ResolvedRegistration, null);
             

LightweightIocContainer/LightweightIocContainer.csproj

@@ -9,7 +9,7 @@
     <LangVersion>default</LangVersion>
     <Nullable>enable</Nullable>
     <DocumentationFile>LightweightIocContainer.xml</DocumentationFile>
-    <VersionPrefix>3.0.0</VersionPrefix>
+    <VersionPrefix>3.0.1</VersionPrefix>
   </PropertyGroup>
 
   <PropertyGroup>

README.md

@@ -16,13 +16,13 @@ The easiest way to [install](https://github.com/SimonG96/LightweightIocContainer
 You can either use the [`PackageManager`](https://github.com/SimonG96/LightweightIocContainer/wiki/Install-Lightweight-IOC-Container#packagemanager) in VisualStudio:
 
 ```PM
-PM> Install-Package LightweightIocContainer -Version 3.0.0
+PM> Install-Package LightweightIocContainer -Version 3.0.1
 ```
 
 or you can use the [`.NET CLI`](https://github.com/SimonG96/LightweightIocContainer/wiki/Install-Lightweight-IOC-Container#net-cli):
 
 ```.net
-> dotnet add package LightweightIocContainer --version 3.0.0
+> dotnet add package LightweightIocContainer --version 3.0.1
 ```
 
 ### Example usage

Test.LightweightIocContainer/MultiLayerResolveTest.cs

@@ -13,12 +13,12 @@ public class MultiLayerResolveTest
 {
     public interface IA
     {
-        
+        IB BProperty { get; }
     }
     
     public interface IB
     {
-        
+        C C { get; }
     }
     
     [UsedImplicitly]
@@ -36,19 +36,28 @@ public class MultiLayerResolveTest
     [UsedImplicitly]
     private class A : IA
     {
-        [UsedImplicitly]
+        public A(IBFactory bFactory) => BProperty = bFactory.Create(new C("from A"));
-        private readonly IB _b;
+        public IB BProperty { get; }
-        
+    }
-        public A(IBFactory bFactory) => _b = bFactory.Create(new C("from A"));
+    
+    private class OtherA : IA
+    {
+        public OtherA(IB bProperty, IB secondB)
+        {
+            BProperty = bProperty;
+            SecondB = secondB;
+        }
+
+        public IB BProperty { get; }
+        public IB SecondB { get; }
     }
 
     [UsedImplicitly]
     private class B : IB
     {
-        public B(C c)
+        public B(C c) => C = c;
-        {
+
-            
+        public C C { get; }
-        }
     }
     
     [UsedImplicitly]
@@ -82,4 +91,16 @@ public class MultiLayerResolveTest
         IB b = container.Resolve<IB>();
         Assert.IsInstanceOf<B>(b);
     }
+
+    [Test]
+    public void TestResolveSingletonTwiceAsCtorParameterInSameCtor()
+    {
+        IocContainer container = new();
+        container.Register(r => r.Add<IA, OtherA>());
+        container.Register(r => r.Add<IB, B>());
+        container.Register(r => r.Add<C>(Lifestyle.Singleton).WithParameters("test"));
+
+        OtherA a = container.Resolve<OtherA>();
+        Assert.AreEqual(a.BProperty.C, a.SecondB.C);
+    }
 }

Test.LightweightIocContainer/Test.LightweightIocContainer.csproj

@@ -5,7 +5,7 @@
     <IsPackable>false</IsPackable>
     <Authors>SimonG</Authors>
     <LangVersion>default</LangVersion>
-    <VersionPrefix>3.0.0</VersionPrefix>
+    <VersionPrefix>3.0.1</VersionPrefix>
   </PropertyGroup>
 
   <ItemGroup>