Fixes #102

src/Dependency/Injection/Members/InjectionFactory.cs

@@ -79,9 +79,7 @@ public override void AddPolicies<TContext, TPolicySet>(Type registeredType, Type
 
             ResolveDelegate<TContext> CreateLegacyPolicy()
             {
-                return (ref TContext c) =>
-                    _factoryFunc(c.Container, c.Type, c.Name) ??
-                    throw new InvalidOperationException("Injection Factory must return valid object or throw an exception");
+                return (ref TContext c) => _factoryFunc(c.Container, c.Type, c.Name);
             }
 
             ResolveDelegate<TContext> CreatePerResolveLegacyPolicy() 

src/Lifetime/Abstracts/LifetimeManager.cs

@@ -8,6 +8,13 @@ namespace Unity.Lifetime
     /// </summary>
     public abstract class LifetimeManager 
     {
+        /// <summary>
+        /// This value represents Invalid Value. Lifetime manager must return this value
+        /// unless value is set to valid object. Null is a valie value and is not equal 
+        /// to NoValue 
+        /// </summary>
+        public static readonly object NoValue = new InvalidValue();
+
         /// <summary>
         /// A <see cref="Boolean"/> indicating if this manager is being used in 
         /// one of the registrations.
@@ -27,7 +34,7 @@ public abstract class LifetimeManager
         /// </summary>
         /// <param name="container">The container this lifetime is associated with</param>
         /// <returns>the object desired, or null if no such object is currently stored.</returns>
-        public abstract object GetValue(ILifetimeContainer container = null);
+        public virtual object GetValue(ILifetimeContainer container = null) => NoValue;
 
         /// <summary>
         /// Stores the given value into backing store for retrieval later.
@@ -53,13 +60,6 @@ public virtual void RemoveValue(ILifetimeContainer container = null) { }
         /// <returns>A new instance of the appropriate lifetime manager</returns>
         public LifetimeManager CreateLifetimePolicy() => OnCreateLifetimeManager();
 
-        /// <summary>
-        /// Type of current lifetime manager
-        /// </summary>
-        /// <returns>The <see cref="Type"/> of the manager.</returns>
-        [Obsolete("This property will be removed in next major release. Use GetType() instead", false)]
-        public Type LifetimeType => GetType();
-
         #endregion
 
 
@@ -72,5 +72,23 @@ public virtual void RemoveValue(ILifetimeContainer container = null) { }
         protected abstract LifetimeManager OnCreateLifetimeManager();
 
         #endregion
+
+
+        #region Nested Types
+
+        public class InvalidValue
+        {
+            public override bool Equals(object obj)
+            {
+                return ReferenceEquals(this, obj);
+            }
+
+            public override int GetHashCode()
+            {
+                return base.GetHashCode();
+            }
+        }
+
+        #endregion
     }
 }

src/Lifetime/Abstracts/SynchronizedLifetimeManager.cs

@@ -33,7 +33,7 @@ public override object GetValue(ILifetimeContainer container = null)
         {
             Monitor.Enter(_lockObj);
             var result = SynchronizedGetValue(container);
-            if (result != null)
+            if (NoValue != result)
             {
                 Monitor.Exit(_lockObj);
             }

src/Lifetime/Managers/ContainerControlledLifetimeManager.cs

@@ -31,7 +31,7 @@ public class ContainerControlledLifetimeManager : SynchronizedLifetimeManager,
         /// An instance of the object this manager is associated with.
         /// </summary>
         /// <value>This field holds a strong reference to the associated object.</value>
-        protected object Value;
+        protected object Value = NoValue;
 
         private Func<ILifetimeContainer, object> _currentGetValue;
         private Action<object, ILifetimeContainer> _currentSetValue;
@@ -105,12 +105,12 @@ protected override void Dispose(bool disposing)
         {
             try
             {
-                if (Value == null) return;
+                if (NoValue == Value) return;
                 if (Value is IDisposable disposable)
                 {
                     disposable.Dispose();
                 }
-                Value = null;
+                Value = NoValue;
             }
             finally 
             {

src/Lifetime/Managers/ContainerControlledTransientManager.cs

@@ -19,34 +19,19 @@ public override void SetValue(object newValue, ILifetimeContainer container = nu
         }
 
         /// <inheritdoc/>
-        public override object GetValue(ILifetimeContainer container = null)
-        {
-            return null;
-        }
-
-        /// <inheritdoc/>
-        public override void RemoveValue(ILifetimeContainer container = null)
-        {
-        }
+        protected override LifetimeManager OnCreateLifetimeManager() => this;
 
         /// <inheritdoc/>
-        protected override LifetimeManager OnCreateLifetimeManager()
+        public override bool InUse
         {
-            return this;
+            get => false;
+            set { }
         }
 
-        /// <inheritdoc/>
-        public override bool InUse { get => false; set => base.InUse = false; }
-
-
-        #region Overrides
-
         /// <summary>
         /// This method provides human readable representation of the lifetime
         /// </summary>
         /// <returns>Name of the lifetime</returns>
         public override string ToString() => "Lifetime:PerContainerTransient";
-
-        #endregion
     }
 }

src/Lifetime/Managers/ExternallyControlledLifetimeManager.cs

@@ -11,7 +11,14 @@ public class ExternallyControlledLifetimeManager : LifetimeManager,
                                                        ITypeLifetimeManager,
                                                        IFactoryLifetimeManager
     {
-        private WeakReference _value = new WeakReference(null);
+        #region Fields
+
+        private WeakReference _value = new WeakReference(NoValue);
+
+        #endregion
+
+
+        #region Overrides
 
         /// <summary>
         /// Retrieve a value from the backing store associated with this Lifetime policy.
@@ -38,9 +45,6 @@ protected override LifetimeManager OnCreateLifetimeManager()
             return new ExternallyControlledLifetimeManager();
         }
 
-
-        #region Overrides
-
         public override string ToString() => "Lifetime:External";
 
         #endregion

src/Lifetime/Managers/HierarchicalLifetimeManager.cs

@@ -35,11 +35,14 @@ public class HierarchicalLifetimeManager : SynchronizedLifetimeManager,
 
         #endregion
 
+
+        #region Overrides
+
         /// <inheritdoc/>
         protected override object SynchronizedGetValue(ILifetimeContainer container = null)
         {
             return _values.TryGetValue(container ?? throw new ArgumentNullException(nameof(container)), 
-                                       out object value) ? value : null;
+                                       out object value) ? value : NoValue;
         }
 
         /// <inheritdoc/>
@@ -69,6 +72,14 @@ protected override LifetimeManager OnCreateLifetimeManager()
             return new HierarchicalLifetimeManager();
         }
 
+        /// <summary>
+        /// This method provides human readable representation of the lifetime
+        /// </summary>
+        /// <returns>Name of the lifetime</returns>
+        public override string ToString() => "Lifetime:Hierarchical";
+
+        #endregion
+
 
         #region IDisposable
 
@@ -80,14 +91,14 @@ protected override void Dispose(bool disposing)
                 if (0 == _values.Count) return;
 
                 foreach (var disposable in _values.Values
-                    .OfType<IDisposable>()
-                    .ToArray())
+                                                  .OfType<IDisposable>()
+                                                  .ToArray())
                 {
                     disposable.Dispose();
                 }
                 _values.Clear();
             }
-            finally 
+            finally
             {
                 base.Dispose(disposing);
             }
@@ -96,17 +107,6 @@ protected override void Dispose(bool disposing)
         #endregion
 
 
-        #region Overrides
-
-        /// <summary>
-        /// This method provides human readable representation of the lifetime
-        /// </summary>
-        /// <returns>Name of the lifetime</returns>
-        public override string ToString() => "Lifetime:Hierarchical";
-
-        #endregion
-
-
         #region Nested Types
 
         private class DisposableAction : IDisposable

src/Lifetime/Managers/PerResolveLifetimeManager.cs

@@ -10,16 +10,14 @@ public class PerResolveLifetimeManager : LifetimeManager,
                                              IFactoryLifetimeManager,
                                              ITypeLifetimeManager
     {
-        protected object value;
+        #region Fields
 
-        /// <summary>
-        /// Construct a new <see cref="PerResolveLifetimeManager"/> object that does not
-        /// itself manage an instance.
-        /// </summary>
-        public PerResolveLifetimeManager()
-        {
-            value = null;
-        }
+        protected object value = NoValue;
+
+        #endregion
+
+
+        #region Overrides
 
         /// <inheritdoc/>
         public override object GetValue(ILifetimeContainer container = null)
@@ -33,9 +31,6 @@ protected override LifetimeManager OnCreateLifetimeManager()
             return new PerResolveLifetimeManager();
         }
 
-
-        #region Overrides
-
         /// <summary>
         /// This method provides human readable representation of the lifetime
         /// </summary>

src/Lifetime/Managers/PerThreadLifetimeManager.cs

@@ -24,43 +24,33 @@ public class PerThreadLifetimeManager : LifetimeManager,
                                             IFactoryLifetimeManager,
                                             ITypeLifetimeManager
     {
+        #region Fields
+
         [ThreadStatic]
         private static Dictionary<Guid, object> _values;
-        private readonly Guid _key;
+        private readonly Guid _key = Guid.NewGuid();
 
-        /// <summary>
-        /// Initializes a new instance of the <see cref="PerThreadLifetimeManager"/> class.
-        /// </summary>
-        public PerThreadLifetimeManager()
-        {
-            _key = Guid.NewGuid();
-        }
+        #endregion
+
+
+        #region Overrides
 
         /// <inheritdoc/>
         public override object GetValue(ILifetimeContainer container = null)
         {
-            EnsureValues();
+            if (null == _values) return NoValue;
 
-            _values.TryGetValue(_key, out var result);
-
-            return result;
+            return _values.TryGetValue(_key, out var result) ? result : NoValue;
         }
 
         /// <inheritdoc/>
         public override void SetValue(object newValue, ILifetimeContainer container = null)
-        {
-            EnsureValues();
-
-            _values[_key] = newValue;
-        }
-
-        private static void EnsureValues()
         {
             // no need for locking, values is TLS
             if (_values == null)
-            {
                 _values = new Dictionary<Guid, object>();
-            }
+
+            _values[_key] = newValue;
         }
 
         /// <inheritdoc/>
@@ -70,7 +60,6 @@ protected override LifetimeManager OnCreateLifetimeManager()
         }
 
 
-        #region Overrides
 
         /// <summary>
         /// This method provides human readable representation of the lifetime

src/Lifetime/Managers/SingletonLifetimeManager.cs

@@ -33,9 +33,12 @@ public class SingletonLifetimeManager : SynchronizedLifetimeManager,
         /// An instance of the singleton object this manager is associated with.
         /// </summary>
         /// <value>This field holds a strong reference to the singleton object.</value>
-        protected object Value;
+        protected object Value = NoValue;
 
         #endregion
+
+
+        #region Overrides
 
         /// <inheritdoc/>
         protected override object SynchronizedGetValue(ILifetimeContainer container = null)
@@ -61,32 +64,30 @@ protected override LifetimeManager OnCreateLifetimeManager()
             return new SingletonLifetimeManager();
         }
 
+        /// <summary>
+        /// This method provides human readable representation of the lifetime
+        /// </summary>
+        /// <returns>Name of the lifetime</returns>
+        public override string ToString() => "Lifetime:Singleton";
+
+        #endregion
+
+
         #region IDisposable
 
         /// <inheritdoc/>		
         protected override void Dispose(bool disposing)
         {
             base.Dispose(disposing);
 
-            if (Value == null) return;
+            if (NoValue == Value) return;
             if (Value is IDisposable disposable)
             {
                 disposable.Dispose();
             }
-            Value = null;
+            Value = NoValue;
         }
 
         #endregion
-
-
-        #region Overrides
-
-        /// <summary>
-        /// This method provides human readable representation of the lifetime
-        /// </summary>
-        /// <returns>Name of the lifetime</returns>
-        public override string ToString() => "Lifetime:Singleton";
-
-        #endregion
     }
 }