[API Proposal]: Add to ServiceCollectionDescriptorExtensions generic .Replace<T> method

[KSemenenko]

Background and motivation

For replacement implementation in TestHost I should do like this:

 services.RemoveAll<ISomeInterface>();
 services.AddSingleton<ISomeInterface, FakeImplementation>();

Or like this

services.Replace(new ServiceDescriptor(..... ));

So I thought, why not use the Replace method but found that it didn't exist.

API Proposal

namespace Microsoft.Extensions.DependencyInjection.Extensions
{
    public static class ServiceCollectionDescriptorExtensions
    {
        public static bool Replace(this IServiceCollection services, Type serviceType, Func<IServiceProvider, object> factory);
        public static bool Replace<TService>(this IServiceCollection services, Func<IServiceProvider, TService> factory);
        public static bool Replace<TService, TImplementation>(this IServiceCollection services);
    }
}

API Usage

 services.Replace<FakeImplementation>();
 services.Replace<ISomeInterface, FakeImplementation>();
 services.Replace<ISomeInterface>(f=> new FakeImplementation());

Alternative Designs

No response

Risks

The Replace method already exists, it's a new API, so I don't see any serious risks.

[ghost]

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Issue Details

---

### Background and motivation For replacement implementation in TestHost I should do like this: ``` cs services.RemoveAll(); services.AddSingleton< ISomeInterface, FakeImplementation>(); ``` Or like this ``` cs services.Replace(new ServiceDescriptor(..... )); ``` So I thought, why not use the Replace method but found that it didn't exist. ### API Proposal ```C# namespace Microsoft.Extensions.DependencyInjection.Extensions { public static class ServiceCollectionDescriptorExtensions { public static bool Replace(this IServiceCollection services, Type serviceType, Func factory); public static bool Replace(this IServiceCollection services, Func factory); public static bool Replace(this IServiceCollection services); } } ``` ### API Usage ``` cs services.Replace(); services.Replace(); services.Replace(f=> new FakeImplementation()); ``` ### Alternative Designs _No response_ ### Risks The Replace method already exists, it's a new API, so I don't see any serious risks.

Author:	KSemenenko
Assignees:	-
Labels:	`api-suggestion`, `untriaged`, `area-Extensions-DependencyInjection`
Milestone:	-

[KSemenenko]

If it's a good idea, I'm happy to implement it.

[KSemenenko]

I think lifetime should be the same, as you mention it’s for testing