ServiceProviderCache keeps initially created IServiceProvider indefinitely

[PawelGerr]

The ServiceProviderCache uses instances of IDbContextOptions as keys for the internal ConcurrentDictionary. A key of type IDbContextOptions contains, among other things, the extension CoreOptionsExtension which has an _applicationServiceProvider.

After creation and disposal of the first DbContext the ServiceProviderCache keeps the IDbContextOptions incl. the (disposed) IServiceProvider, which keeps all IDisposable instances in it. One of the disposables is the DbContext itself.

The result is that the reference _applicationServiceProvider prevents GC to reclaim the memory.

Repro

Program.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.Extensions.DependencyInjection;

var rootServiceProvider = new ServiceCollection()
                          .AddDbContext<DemoDbContext>(builder =>
                                 builder.UseSqlServer("server=localhost;database=demo;integrated security=true"))
                          .BuildServiceProvider();

CreateAndDisposeContext(rootServiceProvider);

var cache = ServiceProviderCache.Instance;

static void CreateAndDisposeContext(IServiceProvider rootServiceProvider)
{
   using var scope = rootServiceProvider.CreateScope();

   scope.ServiceProvider.GetRequiredService<DemoDbContext>();
}


public class DemoDbContext : DbContext
{
   public DemoDbContext(DbContextOptions<DemoDbContext> options)
      : base(options)
   {
   }
}

csproj file

<Project Sdk="Microsoft.NET.Sdk">

   <PropertyGroup>
      <OutputType>Exe</OutputType>
      <TargetFramework>net6.0</TargetFramework>
      <ImplicitUsings>enable</ImplicitUsings>
      <Nullable>enable</Nullable>
   </PropertyGroup>

   <ItemGroup>
     <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="6.0.1" />
   </ItemGroup>

</Project>

Provider and version information

EF Core version: 6.0.1
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 6.0
Operating system: Windows 10 x64
IDE: Rider 2021.3.2

[ajcvickers]

@AndriySvyryd This looks like a consequence of no longer just using the hash. I now remember that this was why we did it the hash way in the first place!