EF Core 6 RC1 breaks extensions due to a change in a contract

File a bug

After updating my project to EF Core 6 RC1, extensions installed with the project stopped working due to a contract change:

Before: https://github.com/dotnet/efcore/blob/v5.0.10/src/EFCore/Infrastructure/DbContextOptionsExtensionInfo.cs#L49

public abstract class DbContextOptionsExtensionInfo {
    ....
    public abstract long GetServiceProviderHashCode();
}

After: https://github.com/dotnet/efcore/blob/v6.0.0-rc.1.21452.10/src/EFCore/Infrastructure/DbContextOptionsExtensionInfo.cs#L49

public abstract class DbContextOptionsExtensionInfo {
    ....
    public abstract int GetServiceProviderHashCode();
}

GetServiceProviderHashCode has a new return type of int rather than long. This causes the following exception in production when loading an extension that was compiled against a previous EF Core version:

System.TypeLoadException: 'Method 'GetServiceProviderHashCode' in type 'ExtensionInfo' from assembly 'EntityFrameworkCore.Projectables, Version=1.0.0.0, Culture=neutral, PublicKeyToken=fc5550082a9c642c' does not have an implementation.'

A simple reproduction using: EntityFrameworkCore.Projectables:

 var serviceProvider = new ServiceCollection()
    .AddDbContext<ApplicationDbContext>(options => {
        options
             .UseSqlite(dbConnection)
             .UseProjectables() // Include our custom extension
         })
    .BuildServiceProvider();

// Causes System.TypeLoadException when targeting EF Core 6 RC1. Runs fine when targeting EF Core 6 preview 7 or earlier (including EF Core 5 and 3.1)
var dbContext = serviceProvider.GetRequiredService<ApplicationDbContext>(); 

EF Core version: 6.0.0-rc.1.21451.13 Database provider: (e.g. Microsoft.EntityFrameworkCore.SqlServer) Target framework: (e.g. .NET 6.0 RC 1) Operating system: Windows IDE: (e.g. Visual Studio 2022 17.4)

[AndriySvyryd]

Would fix this breaking change while still allowing extension authors to give an implementation to ShouldUseSameServiceProvider. Providing a custom implementation only affects EF Core 6 and beyond. Not providing an implementation means that there is still the chance of hash collisions.

Yes, I understand that your proposal allows extensions to work with EF Core 6 without fixing the original issue. But this issue is hard to debug and workaround when it happens, so we decided to take a break and fix it for good this time.

Note that 3.1 and 5.0 will go out of support next year: Releases

[ajcvickers]

@koenbeuk It’s more involved than that. I already discussed with @AndriySvyryd whether there was a reasonable way to avoid this. He can explain more if you want to pursue this.