'EnsureDeletedAsync broken after upgrade, .NET 3.1 to .NET 6

I'm working on a .NET Core application in Visual Studio 2022 on Windows 10. I'm using Entity Framework Core and, for unit testing, MSTest. I have the following code in my unit test project to initialize the database context and to clear the database between tests:

public static MyDbContext DbContext;

...

public async static Task InitializeDatabase()
{
    ConfigureDbContext();
    try
    {
        await DbContext.Database.EnsureDeletedAsync();
    } catch(Exception e) // I just added this so I'd have a place to put a breakpoint for debugging
    {
        throw;
    }
}

private static void ConfigureDbContext()
{
    MemoryCacheOptions memoryCacheOptions = new MemoryCacheOptions
    {
        SizeLimit = 10000000
    };
    IMemoryCache cache = new MemoryCache(new MemoryCacheOptions());
    DbContextOptions<MyDbContext> options = new DbContextOptionsBuilder<MyDbContext>()
        .UseInMemoryDatabase("DataInMemory")
        .Options;
    DbContext = new MyDbContext(options);
}

This worked fine under .NET Core 3.1. I migrated to .NET Core 6, including a move to the latest version of the Microsoft.EntityFrameworkCore packages. Now the call to DbContext.Database.EnsureDeletedAsync() throws the following exception:

System.InvalidOperationException: 'There are multiple [ForeignKey] attributes which are pointing to same set of properties '{'ParentId'}' on entity type 'BusinessLine' and targeting the principal entity type 'BusinessLine'.'

I'm confused by this in two ways. First, if the foreign keys are a barrier to the application figuring out how to accomplish this, why weren't they a barrier under .NET 3.1?

Second, according to the Microsoft documentation, what EnsureDeletedAsync does is delete the database outright. Here, my confusion further branches in two directions. (a) If the database is being deleted outright, then what do the foreign key relationships among the tables within a database have to do with deleting the database altogether? (b) I see now that what's prescribed is for EnsureDeletedAsync to be followed by EnsureCreatedAsync. My code lacks the latter, yet, somehow, before the migration, my code worked.

So, does EnsureDeletedAsync delete data from tables while leaving the tables, as well as the database, in existence. Or does it wipe out the entire database? Can somebody help sort this out for me, and point me in the direction of a once-again working unit test project?

Update: The code for BusinessLine is here:

    public class BusinessLine
    {
        public int BusinessLineId { get; set; }

        [ForeignKey("DataDescriptor")]
        public int DataDescriptorId { get; set; }

        public int Level { get; set; }

        [ForeignKey("Parent")]
        public int? ParentId { get; set; }

        [ForeignKey("AssetClass")]
        public int? AssetClassId { get; set; }

        public string BusinessLineName { get; set; }

        [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
        public string UpdatedBy { get; set; }

        [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
        public DateTime UpdateDateTime { get; set; }

        // Foreign key relationships
        public BusinessLine Parent { get; set; }

        public AssetClass AssetClass { get; set; }

        public DataDescriptor DataDescriptor { get; set; }

        [ForeignKey("ParentId")]
        public List<BusinessLine> Sublines { get; set; }

    }
}

It has a foreign key relationship to itself because it's hierarchical.

The stack trace:

   at Microsoft.EntityFrameworkCore.Metadata.Conventions.ForeignKeyAttributeConvention.UpdateRelationshipBuilder(IConventionForeignKeyBuilder relationshipBuilder, IConventionContext context)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.ForeignKeyAttributeConvention.ProcessForeignKeyAdded(IConventionForeignKeyBuilder relationshipBuilder, IConventionContext`1 context)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ImmediateConventionScope.OnForeignKeyAdded(IConventionForeignKeyBuilder relationshipBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnForeignKeyAddedNode.Run(ConventionDispatcher dispatcher)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.DelayedConventionScope.Run(ConventionDispatcher dispatcher)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ConventionBatch.Run()
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ConventionBatch.Dispose()
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ImmediateConventionScope.OnModelInitialized(IConventionModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnModelInitialized(IConventionModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.Model..ctor(ConventionSet conventions, ModelDependencies modelDependencies, ModelConfiguration modelConfiguration)
   at Microsoft.EntityFrameworkCore.ModelBuilder..ctor(ConventionSet conventions, ModelDependencies modelDependencies, ModelConfiguration modelConfiguration)
   at Microsoft.EntityFrameworkCore.ModelConfigurationBuilder.CreateModelBuilder(ModelDependencies modelDependencies)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, ModelDependencies modelDependencies)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, ModelCreationDependencies modelCreationDependencies, Boolean designTime)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel(Boolean designTime)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
   at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.<>c.<TryAddCoreServices>b__8_4(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass2_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.EntityFrameworkCore.DbContext.get_DbContextDependencies()
   at Microsoft.EntityFrameworkCore.DbContext.get_ContextServices()
   at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
   at Microsoft.EntityFrameworkCore.DbContext.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure<System.IServiceProvider>.get_Instance()
   at Microsoft.EntityFrameworkCore.Infrastructure.Internal.InfrastructureExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.get_Dependencies()
   at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.EnsureDeletedAsync(CancellationToken cancellationToken)
   at [...].UnitTests.Overhead.Common.<InitializeDatabase>d__12.MoveNext() in [...].UnitTests\Overhead\Common.cs:line 195

Solution 1:^[1]

    [ForeignKey("ParentId")]
    public List<BusinessLine> Sublines { get; set; }

That's not how the foreign key attribute is supposed to be called. Simply delete it and it will fix this problem.

In fact, you don't need any foreign key attributes at all, you're polluting your class for no reason. The id + object reference pattern is enough to build the table structure.

Sources

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Source: Stack Overflow

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Solution 1	Blindy

'EnsureDeletedAsync broken after upgrade, .NET 3.1 to .NET 6

Solution 1:[1]

Sources

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