Change IStateManager.StartTrackingFromQuery to use ISnapshot instead …

…of ValueBuffer

Fixes #31117
Part of #26544

src/EFCore.Relational/Query/RelationalShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.cs

@@ -1204,10 +1204,13 @@ protected override Expression VisitMethodCall(MethodCallExpression methodCallExp
 
                     if (property!.IsPrimaryKey())
                     {
-                        return MakeIndex(
+                        var valueExpression = MakeIndex(
                             keyPropertyValuesParameter,
                             ObjectArrayIndexerPropertyInfo,
                             new[] { Constant(index) });
+                        return methodCallExpression.Type != valueExpression.Type
+                            ? Convert(valueExpression, methodCallExpression.Type)
+                            : valueExpression;
                     }
 
                     var jsonReaderManagerParameter = _jsonReaderDataToJsonReaderManagerParameterMapping[jsonReaderDataParameter];
@@ -1266,6 +1269,7 @@ private Expression CreateJsonShapers(
             INavigation? navigation)
         {
             var jsonReaderDataShaperLambdaParameter = Parameter(typeof(JsonReaderData));
+            // TODO: Use ISnapshot instead #26544
             var keyValuesShaperLambdaParameter = Parameter(typeof(object[]));
             var shaperBlockVariables = new List<ParameterExpression>();
             var shaperBlockExpressions = new List<Expression>();
@@ -1554,7 +1558,7 @@ protected override Expression VisitSwitch(SwitchExpression switchExpression)
                         new ValueBufferTryReadValueMethodsFinder(_entityType).FindValueBufferTryReadValueMethods(body);
 
                     BlockExpression jsonEntityTypeInitializerBlock;
-                    //sometimes we have shadow value buffer and sometimes not, but type initializer always comes last
+                    //sometimes we have shadow snapshot and sometimes not, but type initializer always comes last
                     switch (body.Expressions[^1])
                     {
                         case UnaryExpression { Operand: BlockExpression innerBlock } jsonEntityTypeInitializerUnary
@@ -1665,7 +1669,7 @@ protected override Expression VisitSwitch(SwitchExpression switchExpression)
                     // we can't use simple ExpressionReplacingVisitor, because there could be multiple instances of MethodCallExpression for given property
                     // using dedicated mini-visitor that looks for MCEs with a given shape and compare the IProperty inside
                     // order is:
-                    // - shadow value buffer (if there was one)
+                    // - shadow snapshot (if there was one)
                     // - entity construction / property assignments
                     // - navigation fixups
                     // - entity instance variable that is returned as end result
@@ -1675,14 +1679,17 @@ protected override Expression VisitSwitch(SwitchExpression switchExpression)
                     if (body.Expressions[0] is BinaryExpression
                         {
                             NodeType: ExpressionType.Assign,
-                            Right: NewExpression
+                            Right: UnaryExpression
                             {
-                                Arguments: [NewArrayExpression]
+                                NodeType: ExpressionType.Convert,
+                                Operand: NewExpression
                             }
-                        } shadowValueBufferAssignment
-                        && shadowValueBufferAssignment.Type == typeof(ValueBuffer))
+                        } shadowSnapshotAssignment
+#pragma warning disable EF1001 // Internal EF Core API usage.
+                        && shadowSnapshotAssignment.Type == typeof(ISnapshot))
+#pragma warning restore EF1001 // Internal EF Core API usage.
                     {
-                        finalBlockExpressions.Add(propertyAssignmentReplacer.Visit(shadowValueBufferAssignment));
+                        finalBlockExpressions.Add(propertyAssignmentReplacer.Visit(shadowSnapshotAssignment));
                     }
 
                     foreach (var jsonEntityTypeInitializerBlockExpression in jsonEntityTypeInitializerBlock.Expressions.ToArray()[..^1])
@@ -1881,7 +1888,7 @@ protected override Expression VisitConditional(ConditionalExpression conditional
                     {
                         Assign(entityAlreadyTrackedVariable, Constant(false)),
 
-                        // shadowValueBuffer = ValueBuffer;
+                        // shadowSnapshot = Snapshot.Empty;
                         ifFalseBlock.Expressions[0],
 
                         // entityType = EntityType;
@@ -1904,20 +1911,20 @@ protected override Expression VisitConditional(ConditionalExpression conditional
                     var newInstanceAssignmentVariables = instanceAssignmentBody.Variables.ToList();
                     var newInstanceAssignmentExpressions = new List<Expression>();
 
-                    // we only need to generate shadowValueBuffer if the entity isn't already tracked
-                    // shadow value buffer can be generated early in the block (default)
+                    // we only need to generate shadowSnapshot if the entity isn't already tracked
+                    // shadow snapshot can be generated early in the block (default)
                     // or after we read all the values from JSON (case when the entity has some shadow properties)
-                    // so we loop through the existing expressions and add the condition to value buffer assignment when we find it
+                    // so we loop through the existing expressions and add the condition to snapshot assignment when we find it
                     // expressions processed here:
-                    // shadowValueBuffer = new ValueBuffer(...)
+                    // shadowSnapshot = new Snapshot(...)
                     // jsonManagerPrm = new Utf8JsonReaderManager(jsonReaderDataPrm);
                     // tokenType = jsonManagerPrm.TokenType;
                     // property_reading_loop(...)
                     // jsonManagerPrm.CaptureState();
                     for (var i = 0; i < 5; i++)
                     {
                         newInstanceAssignmentExpressions.Add(
-                            instanceAssignmentBody.Expressions[i].Type == typeof(ValueBuffer)
+                            instanceAssignmentBody.Expressions[i].Type == typeof(ISnapshot)
                                 ? IfThen(
                                     Not(entityAlreadyTrackedVariable),
                                     instanceAssignmentBody.Expressions[i])

src/EFCore/ChangeTracking/IDependentKeyValueFactory`.cs

@@ -29,6 +29,7 @@ public interface IDependentKeyValueFactory<TKey> : IDependentKeyValueFactory
     /// <param name="key">The key instance.</param>
     /// <returns><see langword="true" /> if the key instance was created; <see langword="false" /> otherwise.</returns>
     [ContractAnnotation("=>true, key:notnull; =>false, key:null")]
+    [Obsolete]
     bool TryCreateFromBuffer(in ValueBuffer valueBuffer, [NotNullWhen(true)] out TKey? key);
 
     /// <summary>

src/EFCore/ChangeTracking/IPrincipalKeyValueFactory`.cs

@@ -31,6 +31,7 @@ public interface IPrincipalKeyValueFactory<TKey> : IPrincipalKeyValueFactory
     /// </summary>
     /// <param name="valueBuffer">The buffer containing key values.</param>
     /// <returns>The key object, or null if any of the key values were null.</returns>
+    [Obsolete]
     object? CreateFromBuffer(ValueBuffer valueBuffer);
 
     /// <summary>

src/EFCore/ChangeTracking/Internal/CurrentValueComparerFactory.cs

@@ -19,73 +19,70 @@ public class CurrentValueComparerFactory
     ///     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 IComparer<IUpdateEntry> Create(IPropertyBase propertyBase)
+    public virtual IComparer<IUpdateEntry> Create(IProperty property)
     {
-        var modelType = propertyBase.ClrType;
+        var modelType = property.ClrType;
         var nonNullableModelType = modelType.UnwrapNullableType();
         if (IsGenericComparable(modelType, nonNullableModelType))
         {
             return (IComparer<IUpdateEntry>)Activator.CreateInstance(
                 typeof(EntryCurrentValueComparer<>).MakeGenericType(modelType),
-                propertyBase)!;
+                property)!;
         }
 
         if (typeof(IStructuralComparable).IsAssignableFrom(nonNullableModelType))
         {
-            return new StructuralEntryCurrentValueComparer(propertyBase);
+            return new StructuralEntryCurrentValueComparer(property);
         }
 
         if (typeof(IComparable).IsAssignableFrom(nonNullableModelType))
         {
-            return new EntryCurrentValueComparer(propertyBase);
+            return new EntryCurrentValueComparer(property);
         }
 
-        if (propertyBase is IProperty property)
+        var converter = property.GetTypeMapping().Converter;
+        if (converter != null)
         {
-            var converter = property.GetTypeMapping().Converter;
-            if (converter != null)
+            var providerType = converter.ProviderClrType;
+            var nonNullableProviderType = providerType.UnwrapNullableType();
+            if (IsGenericComparable(providerType, nonNullableProviderType))
             {
-                var providerType = converter.ProviderClrType;
-                var nonNullableProviderType = providerType.UnwrapNullableType();
-                if (IsGenericComparable(providerType, nonNullableProviderType))
-                {
-                    var elementType = property.GetElementType();
-                    var modelBaseType = elementType != null
-                        ? typeof(IEnumerable<>).MakeGenericType(elementType.ClrType)
-                        : modelType;
-                    var comparerType = modelType.IsClass
-                        ? typeof(NullableClassCurrentProviderValueComparer<,>).MakeGenericType(modelBaseType, providerType)
-                        : modelType == converter.ModelClrType
-                            ? typeof(CurrentProviderValueComparer<,>).MakeGenericType(modelBaseType, providerType)
-                            : typeof(NullableStructCurrentProviderValueComparer<,>).MakeGenericType(
-                                nonNullableModelType, providerType);
+                var elementType = property.GetElementType();
+                var modelBaseType = elementType != null
+                    ? typeof(IEnumerable<>).MakeGenericType(elementType.ClrType)
+                    : modelType;
+                var comparerType = modelType.IsClass
+                    ? typeof(NullableClassCurrentProviderValueComparer<,>).MakeGenericType(modelBaseType, providerType)
+                    : modelType == converter.ModelClrType
+                        ? typeof(CurrentProviderValueComparer<,>).MakeGenericType(modelBaseType, providerType)
+                        : typeof(NullableStructCurrentProviderValueComparer<,>).MakeGenericType(
+                            nonNullableModelType, providerType);
 
-                    return (IComparer<IUpdateEntry>)Activator.CreateInstance(comparerType, propertyBase, converter)!;
-                }
-
-                if (typeof(IStructuralComparable).IsAssignableFrom(nonNullableProviderType))
-                {
-                    return new StructuralEntryCurrentProviderValueComparer(propertyBase, converter);
-                }
+                return (IComparer<IUpdateEntry>)Activator.CreateInstance(comparerType, property, converter)!;
+            }
 
-                if (typeof(IComparable).IsAssignableFrom(nonNullableProviderType))
-                {
-                    return new EntryCurrentProviderValueComparer(propertyBase, converter);
-                }
+            if (typeof(IStructuralComparable).IsAssignableFrom(nonNullableProviderType))
+            {
+                return new StructuralEntryCurrentProviderValueComparer(property, converter);
+            }
 
-                throw new InvalidOperationException(
-                    CoreStrings.NonComparableKeyTypes(
-                        propertyBase.DeclaringType.DisplayName(),
-                        propertyBase.Name,
-                        modelType.ShortDisplayName(),
-                        providerType.ShortDisplayName()));
+            if (typeof(IComparable).IsAssignableFrom(nonNullableProviderType))
+            {
+                return new EntryCurrentProviderValueComparer(property, converter);
             }
+
+            throw new InvalidOperationException(
+                CoreStrings.NonComparableKeyTypes(
+                    property.DeclaringType.DisplayName(),
+                    property.Name,
+                    modelType.ShortDisplayName(),
+                    providerType.ShortDisplayName()));
         }
 
         throw new InvalidOperationException(
             CoreStrings.NonComparableKeyType(
-                propertyBase.DeclaringType.DisplayName(),
-                propertyBase.Name,
+                property.DeclaringType.DisplayName(),
+                property.Name,
                 modelType.ShortDisplayName()));
 
         static bool IsGenericComparable(Type type, Type nonNullableType)

src/EFCore/ChangeTracking/Internal/EmptyShadowValuesFactoryFactory.cs

@@ -13,6 +13,18 @@ namespace Microsoft.EntityFrameworkCore.ChangeTracking.Internal;
 /// </summary>
 public class EmptyShadowValuesFactoryFactory : SnapshotFactoryFactory
 {
+    private EmptyShadowValuesFactoryFactory()
+    {
+    }
+
+    /// <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 readonly EmptyShadowValuesFactoryFactory Instance = new();
+
     /// <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
@@ -55,7 +67,7 @@ protected override bool UseEntityVariable
     ///     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 override Expression CreateReadShadowValueExpression(ParameterExpression? parameter, IPropertyBase property)
+    protected override Expression CreateReadShadowValueExpression(Expression? parameter, IPropertyBase property)
         => Expression.Default(property.ClrType);
 
     /// <summary>
@@ -64,6 +76,6 @@ protected override Expression CreateReadShadowValueExpression(ParameterExpressio
     ///     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 override Expression CreateReadValueExpression(ParameterExpression? parameter, IPropertyBase property)
+    protected override Expression CreateReadValueExpression(Expression? parameter, IPropertyBase property)
         => Expression.Default(property.ClrType);
 }

src/EFCore/ChangeTracking/Internal/EntryCurrentProviderValueComparer.cs

@@ -20,7 +20,7 @@ public class EntryCurrentProviderValueComparer : EntryCurrentValueComparer
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     public EntryCurrentProviderValueComparer(
-        IPropertyBase property,
+        IProperty property,
         ValueConverter converter)
         : base(property)
     {

src/EFCore/ChangeTracking/Internal/EntryCurrentValueComparer.cs

@@ -13,7 +13,7 @@ namespace Microsoft.EntityFrameworkCore.ChangeTracking.Internal;
 /// </summary>
 public class EntryCurrentValueComparer : IComparer<IUpdateEntry>, IEqualityComparer<IUpdateEntry>
 {
-    private readonly IPropertyBase _property;
+    private readonly IProperty _property;
     private readonly IComparer _underlyingComparer;
 
     /// <summary>
@@ -22,7 +22,7 @@ public class EntryCurrentValueComparer : IComparer<IUpdateEntry>, IEqualityCompa
     ///     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 EntryCurrentValueComparer(IPropertyBase property)
+    public EntryCurrentValueComparer(IProperty property)
         : this(property, Comparer.Default)
     {
     }
@@ -33,7 +33,7 @@ public EntryCurrentValueComparer(IPropertyBase property)
     ///     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 EntryCurrentValueComparer(IPropertyBase property, IComparer underlyingComparer)
+    public EntryCurrentValueComparer(IProperty property, IComparer underlyingComparer)
     {
         _property = property;
         _underlyingComparer = underlyingComparer;

src/EFCore/ChangeTracking/Internal/IIdentityMap.cs

@@ -27,22 +27,6 @@ public interface IIdentityMap
     /// </summary>
     IEnumerable<InternalEntityEntry> All();
 
-    /// <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>
-    bool Contains(in ValueBuffer valueBuffer);
-
-    /// <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>
-    bool Contains(IForeignKey foreignKey, in ValueBuffer valueBuffer);
-
     /// <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/ChangeTracking/Internal/ISnapshot.cs

@@ -26,4 +26,13 @@ public interface ISnapshot
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     T GetValue<T>(int index);
+
+    /// <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>
+    bool IsEmpty
+        => false;
 }

src/EFCore/ChangeTracking/Internal/IStateManager.cs

@@ -84,7 +84,7 @@ public interface IStateManager : IResettableService
     InternalEntityEntry StartTrackingFromQuery(
         IEntityType baseEntityType,
         object entity,
-        in ValueBuffer valueBuffer);
+        in ISnapshot snapshot);
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to