Associate the DatabaseRoot with the scoped options instance and not the singleton options.

src/EFCore.InMemory/Extensions/InMemoryServiceCollectionExtensions.cs

@@ -53,7 +53,8 @@ public static IServiceCollection AddEntityFrameworkInMemoryDatabase(this IServic
             .TryAddProviderSpecificServices(
                 b => b
                     .TryAddSingleton<IInMemorySingletonOptions, InMemorySingletonOptions>()
-                    .TryAddSingleton<IInMemoryStoreCache, InMemoryStoreCache>()
+                    .TryAddScoped<IInMemoryStoreProvider, InMemoryStoreProvider>()
+                    .TryAddSingleton<IInMemoryDatabaseRootCache, InMemoryDatabaseRootCache>()
                     .TryAddSingleton<IInMemoryTableFactory, InMemoryTableFactory>()
                     .TryAddScoped<IInMemoryDatabase, InMemoryDatabase>());
 

src/EFCore.InMemory/Infrastructure/Internal/IInMemorySingletonOptions.cs

@@ -17,14 +17,6 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Infrastructure.Internal;
 /// </remarks>
 public interface IInMemorySingletonOptions : ISingletonOptions
 {
-    /// <summary>
-    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
-    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
-    ///     any release. You should only use it directly in your code with extreme caution and knowing that
-    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
-    /// </summary>
-    InMemoryDatabaseRoot? DatabaseRoot { get; }
-
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.InMemory/Infrastructure/Internal/InMemoryOptionsExtension.cs

@@ -38,6 +38,7 @@ public InMemoryOptionsExtension()
     protected InMemoryOptionsExtension(InMemoryOptionsExtension copyFrom)
     {
         _storeName = copyFrom._storeName;
+        _nullabilityCheckEnabled = copyFrom._nullabilityCheckEnabled;
         _databaseRoot = copyFrom._databaseRoot;
     }
 
@@ -170,6 +171,11 @@ public override string LogFragment
 
                     builder.Append("StoreName=").Append(Extension._storeName).Append(' ');
 
+                    if (Extension._databaseRoot is { } root)
+                    {
+                        builder.Append("DatabaseRoot=").Append(root.GetHashCode()).Append(' ');
+                    }
+
                     if (!Extension._nullabilityCheckEnabled)
                     {
                         builder.Append("NullabilityChecksEnabled ");
@@ -185,22 +191,16 @@ public override string LogFragment
         public override int GetServiceProviderHashCode()
         {
             var hashCode = new HashCode();
-            hashCode.Add(Extension._databaseRoot);
             hashCode.Add(Extension._nullabilityCheckEnabled);
             return hashCode.ToHashCode();
         }
 
         public override bool ShouldUseSameServiceProvider(DbContextOptionsExtensionInfo other)
             => other is ExtensionInfo otherInfo
-                && Extension._databaseRoot == otherInfo.Extension._databaseRoot
                 && Extension._nullabilityCheckEnabled == otherInfo.Extension._nullabilityCheckEnabled;
 
         public override void PopulateDebugInfo(IDictionary<string, string> debugInfo)
-        {
-            debugInfo["InMemoryDatabase:DatabaseRoot"]
-                = (Extension._databaseRoot?.GetHashCode() ?? 0).ToString(CultureInfo.InvariantCulture);
-            debugInfo["InMemoryDatabase:NullabilityChecksEnabled"]
+            => debugInfo["InMemoryDatabase:NullabilityChecksEnabled"]
                 = (!Extension._nullabilityCheckEnabled).GetHashCode().ToString(CultureInfo.InvariantCulture);
-        }
     }
 }

src/EFCore.InMemory/Infrastructure/Internal/InMemorySingletonOptions.cs

@@ -23,7 +23,6 @@ public virtual void Initialize(IDbContextOptions options)
 
         if (inMemoryOptions != null)
         {
-            DatabaseRoot = inMemoryOptions.DatabaseRoot;
             IsNullabilityCheckEnabled = inMemoryOptions.IsNullabilityCheckEnabled;
         }
     }
@@ -38,15 +37,6 @@ public virtual void Validate(IDbContextOptions options)
     {
         var inMemoryOptions = options.FindExtension<InMemoryOptionsExtension>();
 
-        if (inMemoryOptions != null
-            && DatabaseRoot != inMemoryOptions.DatabaseRoot)
-        {
-            throw new InvalidOperationException(
-                CoreStrings.SingletonOptionChanged(
-                    nameof(InMemoryDbContextOptionsExtensions.UseInMemoryDatabase),
-                    nameof(DbContextOptionsBuilder.UseInternalServiceProvider)));
-        }
-
         if (inMemoryOptions != null
             && IsNullabilityCheckEnabled != inMemoryOptions.IsNullabilityCheckEnabled)
         {
@@ -57,14 +47,6 @@ public virtual void Validate(IDbContextOptions options)
         }
     }
 
-    /// <summary>
-    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
-    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
-    ///     any release. You should only use it directly in your code with extreme caution and knowing that
-    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
-    /// </summary>
-    public virtual InMemoryDatabaseRoot? DatabaseRoot { get; private set; }
-
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore.InMemory/Query/Internal/InMemoryQueryContextFactory.cs

@@ -13,7 +13,7 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Query.Internal;
 /// </summary>
 public class InMemoryQueryContextFactory : IQueryContextFactory
 {
-    private readonly IInMemoryStore _store;
+    private readonly IInMemoryStoreProvider _storeProvider;
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -23,10 +23,9 @@ public class InMemoryQueryContextFactory : IQueryContextFactory
     /// </summary>
     public InMemoryQueryContextFactory(
         QueryContextDependencies dependencies,
-        IInMemoryStoreCache storeCache,
-        IDbContextOptions contextOptions)
+        IInMemoryStoreProvider storeProvider)
     {
-        _store = storeCache.GetStore(contextOptions);
+        _storeProvider = storeProvider;
         Dependencies = dependencies;
     }
 
@@ -42,5 +41,5 @@ public InMemoryQueryContextFactory(
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     public virtual QueryContext Create()
-        => new InMemoryQueryContext(Dependencies, _store);
+        => new InMemoryQueryContext(Dependencies, _storeProvider.Store);
 }

src/EFCore.InMemory/Storage/Internal/InMemoryStoreCacheExtensions.cs → src/EFCore.InMemory/Storage/Internal/IInMemoryDatabaseRootCache.cs

@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using Microsoft.EntityFrameworkCore.InMemory.Infrastructure.Internal;
-
 namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
 
 /// <summary>
@@ -11,14 +9,13 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
 ///     any release. You should only use it directly in your code with extreme caution and knowing that
 ///     doing so can result in application failures when updating to a new Entity Framework Core release.
 /// </summary>
-public static class InMemoryStoreCacheExtensions
+public interface IInMemoryDatabaseRootCache
 {
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public static IInMemoryStore GetStore(this IInMemoryStoreCache storeCache, IDbContextOptions options)
-        => storeCache.GetStore(options.Extensions.OfType<InMemoryOptionsExtension>().First().StoreName);
+    InMemoryDatabaseRoot SharedRoot { get; }
 }

src/EFCore.InMemory/Storage/Internal/IInMemoryStoreCache.cs → src/EFCore.InMemory/Storage/Internal/IInMemoryStoreProvider.cs

@@ -9,13 +9,13 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
 ///     any release. You should only use it directly in your code with extreme caution and knowing that
 ///     doing so can result in application failures when updating to a new Entity Framework Core release.
 /// </summary>
-public interface IInMemoryStoreCache
+public interface IInMemoryStoreProvider
 {
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    IInMemoryStore GetStore(string name);
+    IInMemoryStore Store { get; }
 }

src/EFCore.InMemory/Storage/Internal/InMemoryDatabase.cs

@@ -11,7 +11,7 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
 /// </summary>
 public class InMemoryDatabase : Database, IInMemoryDatabase
 {
-    private readonly IInMemoryStore _store;
+    private readonly IInMemoryStoreProvider _storeProvider;
     private readonly IUpdateAdapterFactory _updateAdapterFactory;
     private readonly IDiagnosticsLogger<DbLoggerCategory.Update> _updateLogger;
     private readonly IDesignTimeModel _designTimeModel;
@@ -24,14 +24,13 @@ public class InMemoryDatabase : Database, IInMemoryDatabase
     /// </summary>
     public InMemoryDatabase(
         DatabaseDependencies dependencies,
-        IInMemoryStoreCache storeCache,
-        IDbContextOptions options,
+        IInMemoryStoreProvider storeProvider,
         IDesignTimeModel designTimeModel,
         IUpdateAdapterFactory updateAdapterFactory,
         IDiagnosticsLogger<DbLoggerCategory.Update> updateLogger)
         : base(dependencies)
     {
-        _store = storeCache.GetStore(options);
+        _storeProvider = storeProvider;
         _designTimeModel = designTimeModel;
         _updateAdapterFactory = updateAdapterFactory;
         _updateLogger = updateLogger;
@@ -44,7 +43,7 @@ public InMemoryDatabase(
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     public virtual IInMemoryStore Store
-        => _store;
+        => _storeProvider.Store;
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -53,7 +52,7 @@ public virtual IInMemoryStore Store
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     public override int SaveChanges(IList<IUpdateEntry> entries)
-        => _store.ExecuteTransaction(entries, _updateLogger);
+        => Store.ExecuteTransaction(entries, _updateLogger);
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -66,7 +65,7 @@ public override Task<int> SaveChangesAsync(
         CancellationToken cancellationToken = default)
         => cancellationToken.IsCancellationRequested
             ? Task.FromCanceled<int>(cancellationToken)
-            : Task.FromResult(_store.ExecuteTransaction(entries, _updateLogger));
+            : Task.FromResult(Store.ExecuteTransaction(entries, _updateLogger));
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -75,5 +74,5 @@ public override Task<int> SaveChangesAsync(
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     public virtual bool EnsureDatabaseCreated()
-        => _store.EnsureCreated(_updateAdapterFactory, _designTimeModel.Model, _updateLogger);
+        => Store.EnsureCreated(_updateAdapterFactory, _designTimeModel.Model, _updateLogger);
 }

src/EFCore.InMemory/Storage/Internal/InMemoryDatabaseRootCache.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
+
+/// <summary>
+///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+///     any release. You should only use it directly in your code with extreme caution and knowing that
+///     doing so can result in application failures when updating to a new Entity Framework Core release.
+/// </summary>
+public class InMemoryDatabaseRootCache : IInMemoryDatabaseRootCache
+{
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public InMemoryDatabaseRoot SharedRoot { get; } = new();
+}

src/EFCore.InMemory/Storage/Internal/InMemoryDatabaseRootExtensions.cs

@@ -0,0 +1,31 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Concurrent;
+
+namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
+
+/// <summary>
+///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+///     any release. You should only use it directly in your code with extreme caution and knowing that
+///     doing so can result in application failures when updating to a new Entity Framework Core release.
+/// </summary>
+public static class InMemoryDatabaseRootExtensions
+{
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public static IInMemoryStore GetStore(this InMemoryDatabaseRoot root, string name, IInMemoryTableFactory tableFactory)
+    {
+        var instance = (ConcurrentDictionary<string, IInMemoryStore>)
+            LazyInitializer.EnsureInitialized(
+                ref root.Instance,
+                () => new ConcurrentDictionary<string, IInMemoryStore>());
+
+        return instance.GetOrAdd(name, static (_, f) => new InMemoryStore(f), tableFactory);
+    }
+}

src/EFCore.InMemory/Storage/Internal/InMemoryStoreCache.cs → src/EFCore.InMemory/Storage/Internal/InMemoryStoreProvider.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Concurrent;
 using Microsoft.EntityFrameworkCore.InMemory.Infrastructure.Internal;
 
 namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
@@ -12,35 +11,24 @@ namespace Microsoft.EntityFrameworkCore.InMemory.Storage.Internal;
 ///     any release. You should only use it directly in your code with extreme caution and knowing that
 ///     doing so can result in application failures when updating to a new Entity Framework Core release.
 /// </summary>
-public class InMemoryStoreCache : IInMemoryStoreCache
+public class InMemoryStoreProvider : IInMemoryStoreProvider
 {
+    private readonly IDbContextOptions _options;
+    private readonly IInMemoryDatabaseRootCache _databaseRootCache;
     private readonly IInMemoryTableFactory _tableFactory;
-    private readonly ConcurrentDictionary<string, IInMemoryStore> _namedStores;
+    private IInMemoryStore? _store;
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public InMemoryStoreCache(
-        IInMemoryTableFactory tableFactory,
-        IInMemorySingletonOptions? options)
+    public InMemoryStoreProvider(IDbContextOptions options, IInMemoryDatabaseRootCache databaseRootCache, IInMemoryTableFactory tableFactory)
     {
+        _options = options;
+        _databaseRootCache = databaseRootCache;
         _tableFactory = tableFactory;
-
-        if (options?.DatabaseRoot != null)
-        {
-            LazyInitializer.EnsureInitialized(
-                ref options.DatabaseRoot.Instance,
-                () => new ConcurrentDictionary<string, IInMemoryStore>());
-
-            _namedStores = (ConcurrentDictionary<string, IInMemoryStore>)options.DatabaseRoot.Instance;
-        }
-        else
-        {
-            _namedStores = new ConcurrentDictionary<string, IInMemoryStore>();
-        }
     }
 
     /// <summary>
@@ -49,6 +37,19 @@ public InMemoryStoreCache(
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    public virtual IInMemoryStore GetStore(string name)
-        => _namedStores.GetOrAdd(name, _ => new InMemoryStore(_tableFactory));
+    public IInMemoryStore Store
+        => LazyInitializer.EnsureInitialized(ref _store, InitializeStore);
+
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    protected virtual IInMemoryStore InitializeStore()
+    {
+        var extension = _options.Extensions.OfType<InMemoryOptionsExtension>().First();
+        var root = extension.DatabaseRoot ?? _databaseRootCache.SharedRoot;
+        return root.GetStore(extension.StoreName, _tableFactory);
+    }
 }