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DryIoc v3.0.0 Release Notes

Breaking changes

I was trying to keep API surface the same or equivalent to the V2, especially for most general use-cases. If lucky, you just need to recompile. Anyway, I suggest to read the details below.


  • Less features and more feature compose-ability
  • Less code in general and less hacks
  • Smaller and more focused interfaces
  • More polished and gap-less API
  • Features to simplify integration with other libraries
  • Cleanup obsolete code

In detail

OpenScope changes

Now OpenScope is returning IResolverContext instead of full IContainer.

The consequence is that you won't be able to Register on returned scope object. But this is OK because even before, any registration done on scope was actually done on container. This was confusing, because someone may think that registration in scope is separate and will be disposed with the scope.

Old code:

    var container = new Container();

    using (var scope = container.OpenScope())

New code:

    var container = new Container();

    using (var scope = container.OpenScope())

Note: It is still valid to call UseInstance and InjectPropertiesAndFields - the methods are moved to IResolverContext.

No more ImplicitOpenedRootScope

This rule was added to conform to Microsoft.Extensions.DependencyInjection specification to enable the resolution of scoped service both from scoped and the root container. The latter means that the resolved service will be a singleton despite the fact it is registered as scoped.

The rule instructed the DryIoc to open scope on container creation and most importantly, to dispose this scope together with container.

Starting from DryIoc v2.12 the new hybrid Reuse.ScopedOrSingleton was added, so you may not need to open the scope to resolve such a service. This reuse means the Rules.WithImplicitOpenedRootScope is no longer necessary.

Old code:

    var container = new Container(rules => rules.WithImplicitOpenedRootScope());


    container.Resolve<A>(); // Worked, even without an open scope due the rule

New code:

    var container = new Container();

    container.Register<A>(Reuse.ScopedOrSingleton); // The fine-grained and clean intent


Reuse.InResolutionScope changes

InResolutionScope reuse now is just a Scoped reuse

Resolution scope reuse is the lifetime behavior associated with the node in service object graph. Previously resolution scope reuse was separate from scope reuse. It means that scope created via OpenScope did not have any link to scope created for resolved or injected service.

Now it is different and resolution scope is the part of nested open scopes. Therefore resolution scope reuse is just a scoped reuse with the special name, consisting of target resolved/injected service type and/or service key.

That also means Reuse.InResolutionScope which does not specify the type of bound service is just a Reuse.Scoped.

Old code:

    var container = new Container();

    container.Register<A>(Reuse.InResolutionScopeOf(serviceKey: "X"));

    container.Resolve<A>(); // Error! No service with service key "X" is found

New code:

    var container = new Container();

    container.Register<A>(Reuse.ScopedTo(serviceKey: "x"));

    // resolution scope is just a normal scope that can be opened manually
    using (var scope = container.OpenScope(ResolutionScopeName.Of(serviceKey: "x")))
        container.Resolve<A>(); // Works.

Scope is no longer automatically created on Resolve

Previously for any registered service, the call to Resolve may create the scope associated with resolved service, as long the service had a dependency registered with Reuse.InResolutionScope. Now it is no longer happen. The scope will be created only if resolved service is registered with setup: Setup.With(openResolutionScope: true) option.

Old code:

    var container = new Container();


    container.Resolve<A>(); // opens scope and Dependency is successfully injected

New code:

    var container = new Container();

    container.Register<A>(setup: Setup.With(openResolutionScope: true));
    container.Register<Dependency>(Reuse.ScopedTo<A>()); // new syntax, old syntax is obsolete

    container.Resolve<A>(); // opens scope and Dependency is successfully injected

RegisterDelegate parameter changes

IResolver parameter in RegisterDelegate((IResolver resolver) => ...) was extended to IResolverContext. I said 'extended' because IResolverContext implements the IResolver. Because of this, there is a high chance that your code will compile without changes.

Using IResolverContext in delegate will allow you to OpenScope, UseInstance, etc. without need for bringing the correct container instance inside delegate.

Old code:

    var container = new Container();

    container.RegisterDelegate(r => 
        using (var scope => r.Resolver<IContainer>().OpenScope()) { ... }

New code:

    var container = new Container();

    container.RegisterDelegate(r => 
        using (var scope => r.OpenScope()) { ... }

No more FallbackContainers and CreateFacade changes

FallbackContainers were not working fully with the rest of DryIoc features. Therefore multiple issues were reported. So I am happily removing them.

CreateFacade was implemented on top of FallbackContainer and allowed to 'override' facaded container registrations. This behavior may be useful in Tests to override prod service with test mock.

Now CreateFacade is just a sugar on top of Rules.WithFactorySelector(Rules.SelectKeyedOverDefaultFactory(FacadeKey)).

Old code:

    var container = new Container();
    container.Register<IDepOfA, DepOfA>();

    var facade = container.CreateFacade();
    facade.Register<IDepOfA, TestDeoOfA>();

    facade.Resolve<A>(); // will have TestDeoOfA

New code:

    var container = new Container();
    container.Register<IDepOfA, DepOfA>();

    var facade = container.CreateFacade();
    facade.Register<IDepOfA, TestDeoOfA>(ContainerTools.FacadeKey);

    // or with custom key
    var facade = container.CreateFacade("test");
    facade.Register<IDepOfA, TestDeoOfA>("test");

    facade.Resolve<A>(); // will have TestDeoOfA

Property injection changes

Previously, the properties and fields were injected with IfUnresolved.ReturnDefault policy. That means, if matching service was not found (not registered) or there was some other resolution error, the property won't be set. Client does not have any indication of the error, and may assume that property is set. That was done because the property injection is already too relaxed way of injection. If you turning it on, be ready for issues in run-time.

In V3 the situation is improved via new default policy IfUnresolved.ReturnDefaultIfNotRegistered. The policy says that if matching service is not registered, only then skip property setting. For all other kinds of errors, including missing service dependencies, or reuse mismatch, etc. etc., you will get the exception with explaining message.

Given the setup:

class A
    public B B { get; set; }

class B 
    public B(C c) {}

class C {}

Old code:

    var container = new Container();
    container.Register<A>(made: PropertiesAndFields.Auto); // enable property injection for A
    // Skip registration for C

    // Property is not set and no error
    var a = container.Resolve<A>(); 

New code:

    var container = new Container();
    container.Register<A>(made: PropertiesAndFields.Auto); // enable property injection for A
    // Skip registration for C

    // Throws an exception because B is registered but cannot be resolved due its missing dependency C

RequestInfo is merged with Request

RequestInfo was replaced in all APIs with Request. Theoretically, it should not affect the consumers, cause both classes had an identical public API.

RequestInfo was the lightweight version of Request without the runtime information, e.g. reference to container. The separation was required for code generation scenarios, where there are no run-time state available. There were also a performance considerations.

It was always a pain to synchronize between both classes.

Now it is no longer needed, Request now holds an optional runtime information (Container), and may be used as RequestInfo when required.

WeaklyReferenced changes

IDisposable services registered with setup: Setup.With(weaklyReferenced: true) are no longer disposed.

The disposal was not guarantied even before, because the weakly referenced service may be garbage collected at any time.

New Features

Reuse.Scoped and Reuse.ScopedTo for all kinds of scope reuse

More general reuse API




container.Register<B>(Reuse.ScopedTo(serviceKey: "x"));
container.Register<C>(Reuse.ScopedTo(ResolutionScopeName.Of<A>(serviceKey: "x")));

The previous reuse names are not obsolete yet, so no need to change the existing code. The exception is Reuse.InResolutionScope which is marked as Obsolete, and should be replaced either by Reuse.Scoped or specific Reuse.ScopedTo<X>();

Reuse.ScopedTo multiple scope names

Enables to use a single registration for reuse in scopes with specified names:

container.Register<A>(Reuse.ScopedTo("x", "y", "z"));

Resolution scope reuse:

container.Register<C>(Reuse.ScopedTo(ResolutionScopeName.Of<A>(), ResolutionScopeName.Of<B>()));

Register open-generic service with closed implementation

DryIoc now may derive open-generic IFoo<> from closed-generic implementation Foo<object>. In a sense, nothing prevents to do that, but in V2 such registrations where prohibited.

It also may be helpful in some edge RegisterMany scenarios:

container.RegisterMany(implTypes, getServiceTypes: implType => 
    (implType.GetGenericDefinitionOrNull() ?? implType).GetImplementedServiceTypes());

Related issue:

RegisterMany with exact service types you need

The feature is actually demonstrated above. Before, it was possible to provide only the predicate to filter discovered service types. Now you may specify and arbitrary types.

container.RegisterMany(implTypes, getServiceTypes: implType => 
    implType == typeof(Foo<int>) ? new[] { typeof(IFoo<>) } 
        : implType.GetImplementedServiceTypes());

Resolve with user-specified arguments for injection

Resolve method now has an overload to provide custom arguments for injection instead of ones from registered services. It may be useful to pass the runtime data, e.g. connection string. The passed argument is injected into all parameters of matched type in resolved object graph.

    public class X 
        public X(string message, int number) {..}


    var x = container.Resolve<X>(args: new object[] { "hey", 124 });

Note: Passing arguments to Resolve may be combined with other ways to providing custom values, e.g. with Func<TArg1, TArg2.., TResult> wrapper and with per container WithDependencies(..) method.


Additional option to control when to throw exception when service is not resolved / injected.

Resolving with:

  • IfUnresolved.Throw - throws the exception when service is not registered or its dependency is not registered, or cannot be resolved for any other reason.
  • IfUnresolved.ReturnDefault - returns default service value for any above reason
  • IfUnresolved.ReturnDefaultIfNotRegistered - returns default only if service itself is not registered and throws otherwise, e.g. for missing dependency.

Note: The last option now is the default for property injection with PropertiesAndFields.Auto() and .All() selectors.


Like Auto but excludes the fields - may be the only selector you need for property injection.

Func with arguments can be used in Lazy and LazyEnumerable

Now possible:

container.Resolve<LazyEnumerable<Func<string, IService>>>();

This possibility was un-blocked by adding custom args to Resolve(... object[] args) method - so the generated code for Lazy and LazyEnumerable may propagate arguments through Resolve method boundary. Hope, this info may help someone :)

Support used-defined disposal order

By default disposal happens in reverse resolution order - resolved first will be disposed the last. For the service with dependency it means that service will be disposed first then the dependency.

In addition, now you may specify relative disposal order - smallest numbers will be disposed first.

    container.Register<A>(Reuse.Scoped, setup: Setup.With(disposalOrder: -1));

Bug Fixes

  • 505 Failed to register object with ArgumentNullException
  • 521 Rule ConcreteTypeDynamicRegistrations: Exception while resolving instance of class with constructor-injected generic instance of not registered class
  • 538 Ensure that Resolve with provided args is properly cached between multiple open scopes
  • 541 Dynamic registrations: circular dependency is not detected
  • 544 WithTrackingDisposableTransients may downgrade Singletons to Transients
  • 546 Recursive dependencies are not detected in the large object graphs
  • 553 Made.Of(null) causes crash in error handler changed
  • 570 ArgumentNullException thrown when multiple constructors and args dependencies provided
  • 574 IResolverContext.UseInstance() should not have any side effects on other scopes
  • 576 ContainerException should include Type/Registration data
  • 577 Resolve many/keyed factory delegate cache anomaly added: Back RegisterMany with service
  • 579 VerifyResolutions strange behavior
  • 580 Same service instance resolved twice when decorator is used
  • 581 Constructor injection with array parameter

Other changes

  1. Container.cs lost ~3000 LOC.
  2. Using C# 6 through codebase (not a C# 7.* yet)
  3. Umbrella issue is closed:
  4. IReuse contents is replaced with IReuseV3 contents, IReuseV3 is removed.
  5. Removed unused compositeParentKey and compositeRequiredType parameters from IResolver.ResolveMany both in DryIoc and DIZero
  6. Removed scope parameter from Resolve and ResolveMany
  7. Removed state and scope parameter from FactoryDelegate due #288 both in DryIoc and DryIocZero
  8. Removed Rules.FallbackContainers
  9. Container.CreateFacade implementation is changed from fallback containers to rules.WithFactorySelector(Rules.SelectKeyedOverDefaultFactory(FacadeKey))
  10. Removed IScopeAccess interface, replaced with IResolverContext and extension methods.
  11. Removed ContainerWeakRef implementation of IResolverContext. Now IResolverContext is implemented by Container itself.
  12. Added IReuse.Name to support reuse name
  13. Renamed IContainer.ContainerWeakRef into IContainer.ResolverContext
  14. Removed ContainerTools.GetCurrentScope extension. It is replaced by IResolverContext.CurrentScope
  15. Removed obsolete IContainer.EmptyRequest and Request.CreateEmpty
  16. Removed obsolete IContainer.ResolutionStateCache and IContainer.GetOrAddStateItem
  17. Removed obsolete Request.ToRequestInfo
  18. Removed feature outermost parameter of Reuse.InResolutionScopeOf
  19. Removed not necessary trackTransientDisposable parameter from IReuse.Apply method
  20. Removed ResolutionScopeReuse, replaced by CurrentScopeReuse
  21. Changed Reuse.InResolutionScope to be just Reuse.Scoped underneath
  22. Changed obsolete RegisterInstance implementation to just call UseInstance
  23. Removed InstanceFactory which was used by obsolete RegisterInstance
  24. Changed IResolverContext to implement the IResolver instead of holding it as property to simplifies the path to IResolver from the object graph.
  25. Removed unused Request.IsWrappedInFuncWithArgs method
  26. Changed IContainer to implement IResolverContext as it is already does this
  27. Removed IContainer.ResolverContext property
  28. Removed no longer used Request.WithFuncArgs
  29. Changed parameter bool ifUnresolvedReturnDefault to IfUnresolved ifUnresolved in IResolver.Resolve methods to allow to add more IfUnresolved options
  30. renamed: IfAlreadyRegistered parameter to ifAlreadyRegistered in UseInstance methods
  31. Moving OpenScope, UseInstance, InjectPropertiesAndFields from IContainer to IResolverContext
  32. OpenScope no longer accepts the Action<Rules>, but you can always use container.With(Action<Rules>) before opening scope
  33. InjectPropertiesAndFields may define the names of members to inject instead of full blown PropertiesAndFieldsSelector, but there is still possibility to define the selector on container level
  34. Added object[] args parameter into Resolve and ResolveMany
  35. Removed special SingletonScope, using one implementation for both scope and singletons
  36. Removed IScope.GetScopedItemIdOrSelf as it was required only by SingletonScope
  37. Added IScope.TryGet
  38. Moved IContainer.ScopeContext into IResolverContext.ScopeContext
  39. Removed IScopeContext.ScopeContextName, you may provide your name instead
  40. Removed Container.NonAmbientRootScopeName
  41. Disposable services registered with WeaklyReferenced setup are no longer disposed. Because the disposal in this case is optional anyway and the instance may be collected in any given time.
  42. Removed ImplicitOpenedRootScope
  43. Obsoleting WithDefaultReuseInsteadOfTransient replaced by WithDefaultReuse
  44. Changed delegate parameters in RegisterDelegate, RegisterInitializer and RegisterDisposer to accept IResolverContext instead of IResolver
  45. Obsoleting WithAutoFallbackResolution replaced by WithAutoFallbackDynamicRegistration
  46. Moved IContainer.With.. methods to ContainerTools extension methods
  47. Obsoleting AutoFallback and ConcreteType resolution rules
  48. Changed PropertiesAndFields.All to include withBase parameter
  49. Obsoleting the Reuse.InResolutionScope
  50. Removed VerifyResolutions. Replaced with Validate overloads.
  51. Issue #287. Properties default injection policy is changed from IfUnresolved.ReturnDefault to IfUnresolved.ReturnDefaultIfNotRegistered
  52. In IRegister.Register method parameter type IfAlreadyRegistered is changed to IfAlreadyRegistered?
  53. Renamed IRequest.RuntimeParent to IRequest.DirectParent
  54. Renamed IContainer.GetOrAddStateItemExpression to GetConstantExpression
  55. Changed Func<RequestInfo, bool> conditions from APIs to full Request, Func<RequestInfo, bool>
  56. Replacing OpenScope(string name) with WithScope(IScope scope) and making openScope just an extension method in ResolverContext
  57. Removed RequestInfo
  58. Changed GenerateResolutionExpressions argument
  59. Moved SetupAsResolutionRoot to ContainerTools
  60. MaxObjectGraphSize is replaced by DependencyDepthToSplitObjectGraph