MEF2: Cannot get the same instance with ```SharedAttribute```.

[Wenveo]

Nuget Package: System.Composition v6.0.0

Code:

// See https://aka.ms/new-console-template for more information

using System.Composition;
using System.Composition.Hosting;
using System.Reflection;


var container = new ContainerConfiguration()
    .WithAssembly(Assembly.GetExecutingAssembly())
    .CreateContainer();

var mainApp = container.GetExport<MainApp>();
mainApp.Invoke();

[Shared]
[Export]
class MainApp
{
    readonly ITestServiceImpl testService;

    [ImportingConstructor]
    public MainApp(ITestServiceImpl testService)
    {
        this.testService = testService;
    }

    public void Invoke()
    {
        this.testService.Value = 4;
        this.testService.Initialize();
    }
}

interface ITestItem
{

}

interface ITestService
{
    void PrintValue();
}

interface ITestServiceImpl : ITestService
{
    int Value { get; set; }

    void Initialize();
}

[Shared]
[Export(typeof(ITestServiceImpl)), Export(typeof(ITestService))]
class TestService : ITestServiceImpl
{
    readonly IEnumerable<Lazy<ITestItem>> mefItems;

    public int Value { get; set; }

    [ImportingConstructor]
    public TestService([ImportMany] IEnumerable<Lazy<ITestItem>> mefItems)
    {
        this.mefItems = mefItems;
    }


    public void PrintValue()
    {
        Console.WriteLine(Value);
    }


    public void Initialize()
    {
        foreach (var item in this.mefItems)
        {
            var value = item.Value;
        }
    }
}

[Shared]
[Export(typeof(ITestItem))]
class TestItemA : ITestItem
{
    [ImportingConstructor]
    public TestItemA(ITestService testService)
    {
        testService.PrintValue();
    }
}


[Shared]
[Export(typeof(ITestItem))]
class TestItemB : ITestItem
{
    [ImportingConstructor]
    public TestItemB(ITestService testService)
    {
        testService.PrintValue();
    }
}

Description:
In MainApp.Invoke, The Value has been changed.
But PrintValue always print 0.

During debugging, the TestService constructor is called twice (Two instances were created).
The first call is from MainApp, but the second call is from TestItemA?
(MainApp and TestItemA each have two different instances (TestService))

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[Wenveo]

If I GetExport the ITestService, that's only going to have one instance and PrintValue is going to print the correct value.

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Issue Details

---

Nuget Package: System.Composition v6.0.0

Code:

// See https://aka.ms/new-console-template for more information

using System.Composition;
using System.Composition.Hosting;
using System.Reflection;


var container = new ContainerConfiguration()
    .WithAssembly(Assembly.GetExecutingAssembly())
    .CreateContainer();

var mainApp = container.GetExport<MainApp>();
mainApp.Invoke();

[Shared]
[Export]
class MainApp
{
    readonly ITestServiceImpl testService;

    [ImportingConstructor]
    public MainApp(ITestServiceImpl testService)
    {
        this.testService = testService;
    }

    public void Invoke()
    {
        this.testService.Value = 4;
        this.testService.Initialize();
    }
}

interface ITestItem
{

}

interface ITestService
{
    void PrintValue();
}

interface ITestServiceImpl : ITestService
{
    int Value { get; set; }

    void Initialize();
}

[Shared]
[Export(typeof(ITestServiceImpl)), Export(typeof(ITestService))]
class TestService : ITestServiceImpl
{
    readonly IEnumerable<Lazy<ITestItem>> mefItems;

    public int Value { get; set; }

    [ImportingConstructor]
    public TestService([ImportMany] IEnumerable<Lazy<ITestItem>> mefItems)
    {
        this.mefItems = mefItems;
    }


    public void PrintValue()
    {
        Console.WriteLine(Value);
    }


    public void Initialize()
    {
        foreach (var item in this.mefItems)
        {
            var value = item.Value;
        }
    }
}

[Shared]
[Export(typeof(ITestItem))]
class TestItemA : ITestItem
{
    [ImportingConstructor]
    public TestItemA(ITestService testService)
    {
        testService.PrintValue();
    }
}


[Shared]
[Export(typeof(ITestItem))]
class TestItemB : ITestItem
{
    [ImportingConstructor]
    public TestItemB(ITestService testService)
    {
        testService.PrintValue();
    }
}

Description:
In MainApp.Invoke, The Value has been changed.
But PrintValue always print 0.

During debugging, the TestService constructor is called twice (Two instances were created).
The first call is from MainApp, but the second call is from TestItemA?
(MainApp and TestItemA each have two different instances (TestService))

Author:	Noisrev
Assignees:	-
Labels:	area-System.Composition, untriaged
Milestone:	-