Merge pull request #35 from hadashiA/ku/fix-scoped-singleton2

Fix a problem with duplicate instances when resolving a Singleton  from a child scope

Author: hadashiA

VContainer/Assets/VContainer/Runtime/Container.cs

@@ -67,7 +67,7 @@ public object Resolve(IRegistration registration)
                     {
                         return sharedInstances.GetOrAdd(registration, createInstance).Value;
                     }
-                    return Parent.Resolve(registration);
+                    return (Parent.Parent is null ? Parent.Root : Parent).Resolve(registration);
 
                 case Lifetime.Scoped:
                     var lazy = sharedInstances.GetOrAdd(registration, createInstance);

VContainer/Assets/VContainer/Tests/ScopedContainerTest.cs

@@ -120,10 +120,12 @@ public void CreateScopeWithRegisterSingleton()
             {
                 var parentSingleton = grandChildContainer.Resolve<NoDependencyServiceA>();
                 Assert.That(parentSingleton, Is.InstanceOf<NoDependencyServiceA>());
+                Assert.That(parentSingleton, Is.EqualTo(parentContainer.Resolve<NoDependencyServiceA>()));
 
                 var childSingleton = grandChildContainer.Resolve<ServiceA>();
                 Assert.That(childSingleton, Is.InstanceOf<ServiceA>());
                 Assert.That(childSingleton.Service2, Is.InstanceOf<I2>());
+                Assert.That(childSingleton, Is.EqualTo(childContainer.Resolve<ServiceA>()));
 
                 var grandChildSingleton = grandChildContainer.Resolve<ServiceB>();
                 Assert.That(grandChildSingleton, Is.InstanceOf<ServiceB>());