Feature/optimize closures

src/EntityFrameworkCore.Projectables/Services/ProjectableExpressionReplacer.cs

@@ -1,4 +1,5 @@
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -22,14 +23,21 @@ public sealed class ProjectableExpressionReplacer : ExpressionVisitor
         private IEntityType? _entityType;
 
         // Extract MethodInfo via expression trees (trim-safe; computed once per AppDomain)
-        private static readonly MethodInfo _select =
+        private readonly static MethodInfo _select =
             ((MethodCallExpression)((Expression<Func<IQueryable<object>, IQueryable<object>>>)
                 (q => q.Select(x => x))).Body).Method.GetGenericMethodDefinition();
 
-        private static readonly MethodInfo _where =
+        private readonly static MethodInfo _where =
             ((MethodCallExpression)((Expression<Func<IQueryable<object>, IQueryable<object>>>)
                 (q => q.Where(x => true))).Body).Method.GetGenericMethodDefinition();
 
+        // Static caches — keyed by CLR type, shared across all instances for the AppDomain lifetime.
+        // Safe because: type metadata is immutable, LambdaExpression trees are immutable, MethodInfo is stable.
+        private readonly static ConcurrentDictionary<Type, bool> _compilerGeneratedClosureCache = new();
+        private readonly static ConcurrentDictionary<Type, PropertyInfo[]> _projectablePropertiesCache = new();
+        private readonly static ConcurrentDictionary<Type, MethodInfo> _closedSelectCache = new();
+        private readonly static ConcurrentDictionary<Type, MethodInfo> _closedWhereCache = new();
+
         public ProjectableExpressionReplacer(IProjectionExpressionResolver projectionExpressionResolver, bool trackByDefault = false)
         {
             _trackingByDefault = trackByDefault;
@@ -84,7 +92,6 @@ bool TryGetReflectedExpression(MemberInfo memberInfo, [NotNullWhen(true)] out La
                     //     // case of a first()
                     //     return obj.MyMap(x => new Obj {});
                     // }
-
 
                     if (call.Method.ReturnType.IsAssignableTo(typeof(IQueryable)))
                     {
@@ -101,7 +108,9 @@ bool TryGetReflectedExpression(MemberInfo memberInfo, [NotNullWhen(true)] out La
                             // before the query become executed by EF (before the .First()), we rewrite the .First(where)
                             // as .Where(where).Select(x => ...).First()
 
-                            var where = Expression.Call(null, _where.MakeGenericMethod(_entityType.ClrType), call.Arguments);
+                            var whereMethod = _closedWhereCache.GetOrAdd(
+                                _entityType.ClrType, static (t, m) => m.MakeGenericMethod(t), _where);
+                            var where = Expression.Call(null, whereMethod, call.Arguments);
                             // The call instance is based on the wrong polymorphied method.
                             var first  = call.Method.DeclaringType?.GetMethods()
                                 .FirstOrDefault(x => x.Name == call.Method.Name && x.GetParameters().Length == 1);
@@ -138,18 +147,27 @@ bool TryGetReflectedExpression(MemberInfo memberInfo, [NotNullWhen(true)] out La
         protected override Expression VisitMethodCall(MethodCallExpression node)
         {
             // Replace MethodGroup arguments with their reflected expressions.
-            // Note that MethodCallExpression.Update returns the original Expression if argument values have not changed.
-            node = node.Update(node.Object, node.Arguments.Select(arg => arg switch {
-                UnaryExpression {
-                    NodeType: ExpressionType.Convert,
-                    Operand: MethodCallExpression {
-                        NodeType: ExpressionType.Call,
-                        Method: { Name: nameof(MethodInfo.CreateDelegate), DeclaringType.Name: nameof(MethodInfo) },
-                        Object: ConstantExpression { Value: MethodInfo methodInfo }
-                    }
-                } => TryGetReflectedExpression(methodInfo, out var expressionArg) ? expressionArg : arg,
-                _ => arg
-            }));
+            // No-alloc fast-path: scan args without allocating; only copy the array and call
+            // Update() when a replacement is actually found (method-group arguments are rare).
+            Expression[]? updatedArgs = null;
+            for (var i = 0; i < node.Arguments.Count; i++)
+            {
+                if (node.Arguments[i] is UnaryExpression {
+                        NodeType: ExpressionType.Convert,
+                        Operand: MethodCallExpression {
+                            NodeType: ExpressionType.Call,
+                            Method: { Name: nameof(MethodInfo.CreateDelegate), DeclaringType.Name: nameof(MethodInfo) },
+                            Object: ConstantExpression { Value: MethodInfo capturedMethodInfo }
+                        }
+                    } && TryGetReflectedExpression(capturedMethodInfo, out var expressionArg))
+                {
+                    (updatedArgs ??= [.. node.Arguments])[i] = expressionArg;
+                }
+            }
+            if (updatedArgs is not null)
+            {
+                node = node.Update(node.Object, updatedArgs);
+            }
 
             // Get the overriding methodInfo based on te type of the received of this expression
             var methodInfo = node.Object?.Type.GetConcreteMethod(node.Method) ?? node.Method;
@@ -172,7 +190,7 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
             {
                 for (var parameterIndex = 0; parameterIndex < reflectedExpression.Parameters.Count; parameterIndex++)
                 {
-                    var parameterExpession = reflectedExpression.Parameters[parameterIndex];
+                    var parameterExpression = reflectedExpression.Parameters[parameterIndex];
                     var mappedArgumentExpression = (parameterIndex, node.Object) switch {
                         (0, not null) => node.Object,
                         (_, not null) => node.Arguments[parameterIndex - 1],
@@ -181,7 +199,7 @@ protected override Expression VisitMethodCall(MethodCallExpression node)
 
                     if (mappedArgumentExpression is not null)
                     {
-                        _expressionArgumentReplacer.ParameterArgumentMapping.Add(parameterExpession, mappedArgumentExpression);
+                        _expressionArgumentReplacer.ParameterArgumentMapping.Add(parameterExpression, mappedArgumentExpression);
                     }
                 }
 
@@ -232,19 +250,31 @@ protected override Expression VisitMember(MemberExpression node)
         {
             // Evaluate captured variables in closures that contain EF queries to inline them into the main query
             if (node.Expression is ConstantExpression constant &&
-                constant.Type.Attributes.HasFlag(TypeAttributes.NestedPrivate) &&
-                Attribute.IsDefined(constant.Type, typeof(CompilerGeneratedAttribute), inherit: true))
+                IsCompilerGeneratedClosure(constant.Type))
             {
                 try
                 {
-                    var value = Expression
-                        .Lambda<Func<object>>(Expression.Convert(node, typeof(object)))
-                        .Compile()
-                        .Invoke();
+                    // Cheap type check first: only call GetValue() when the member could
+                    // possibly hold an IQueryable.  FieldType / PropertyType are free
+                    // property reads on an already-materialised MemberInfo object.
+                    var memberType = node.Member switch {
+                        FieldInfo field => field.FieldType,
+                        PropertyInfo prop => prop.PropertyType,
+                        _ => null
+                    };
 
-                    if (value is IQueryable queryable && ReferenceEquals(queryable.Provider, _currentQueryProvider))
+                    if (memberType is not null && typeof(IQueryable).IsAssignableFrom(memberType))
                     {
-                        return Visit(queryable.Expression);
+                        var value = node.Member switch {
+                            FieldInfo field => field.GetValue(constant.Value),
+                            PropertyInfo prop => prop.GetValue(constant.Value),
+                            _ => null
+                        };
+
+                        if (value is IQueryable queryable && ReferenceEquals(queryable.Provider, _currentQueryProvider))
+                        {
+                            return Visit(queryable.Expression);
+                        }
                     }
                 }
                 catch
@@ -275,16 +305,10 @@ PropertyInfo property when nodeExpression is not null
                     var updatedBody = _expressionArgumentReplacer.Visit(reflectedExpression.Body);
                     _expressionArgumentReplacer.ParameterArgumentMapping.Clear();
 
-                    return base.Visit(
-                        updatedBody
-                    );
-                }
-                else
-                {
-                    return base.Visit(
-                        reflectedExpression.Body
-                    );
+                    return base.Visit(updatedBody);
                 }
+
+                return base.Visit(reflectedExpression.Body);
             }
 
             return base.VisitMember(node);
@@ -303,12 +327,13 @@ protected override Expression VisitExtension(Expression node)
 
         private Expression _AddProjectableSelect(Expression node, IEntityType entityType)
         {
-            var projectableProperties = entityType.ClrType.GetProperties()
-                .Where(x => x.IsDefined(typeof(ProjectableAttribute), false))
-                .Where(x => x.CanWrite)
-                .ToList();
+            var projectableProperties = _projectablePropertiesCache.GetOrAdd(
+                entityType.ClrType,
+                static t => t.GetProperties()
+                    .Where(x => x.IsDefined(typeof(ProjectableAttribute), false) && x.CanWrite)
+                    .ToArray());
 
-            if (!projectableProperties.Any())
+            if (projectableProperties.Length == 0)
             {
                 return node;
             }
@@ -327,7 +352,8 @@ private Expression _AddProjectableSelect(Expression node, IEntityType entityType
                 .Where(x => projectableProperties.All(y => x.Name != y.Name && x.Name != $"<{y.Name}>k__BackingField"));
 
             // Replace db.Entities to db.Entities.Select(x => new Entity { Property1 = x.Property1, Rewritted = rewrittedProperty })
-            var select = _select.MakeGenericMethod(entityType.ClrType, entityType.ClrType);
+            var select = _closedSelectCache.GetOrAdd(
+                entityType.ClrType, static (t, m) => m.MakeGenericMethod(t, t), _select);
             var xParam = Expression.Parameter(entityType.ClrType);
             return Expression.Call(
                 null,
@@ -354,5 +380,12 @@ private Expression _GetAccessor(PropertyInfo property, ParameterExpression para)
             _expressionArgumentReplacer.ParameterArgumentMapping.Clear();
             return base.Visit(updatedBody);
         }
+
+        private static bool IsCompilerGeneratedClosure(Type type) =>
+            // TypeAttributes.NestedPrivate is a cheap flag check that rules out most types before
+            // touching the attribute cache.
+            type.Attributes.HasFlag(TypeAttributes.NestedPrivate) &&
+            _compilerGeneratedClosureCache.GetOrAdd(type, static t =>
+                Attribute.IsDefined(t, typeof(CompilerGeneratedAttribute), inherit: true));
     }
 }

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaAny.DotNet10_0.verified.txt

@@ -0,0 +1,6 @@
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 1 AND [e0].[Id] <= 5 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaAny.DotNet9_0.verified.txt

@@ -0,0 +1,6 @@
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 1 AND [e0].[Id] <= 5 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaAny.verified.txt

@@ -0,0 +1,6 @@
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 1 AND [e0].[Id] <= 5 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaCount.DotNet10_0.verified.txt

@@ -0,0 +1,5 @@
+SELECT [e].[Id], (
+    SELECT COUNT(*)
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] * 2 > 4) AS [SubsetCount]
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaCount.DotNet9_0.verified.txt

@@ -0,0 +1,5 @@
+SELECT [e].[Id], (
+    SELECT COUNT(*)
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] * 2 > 4) AS [SubsetCount]
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIQueryableField_SubqueryInlinedViaCount.verified.txt

@@ -0,0 +1,5 @@
+SELECT [e].[Id], (
+    SELECT COUNT(*)
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] * 2 > 4) AS [SubsetCount]
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIntField_UsedInProjectableMethod.DotNet10_0.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @lowerBound int = 3;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @lowerBound AND [e].[Id] <= 10

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIntField_UsedInProjectableMethod.DotNet9_0.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @__lowerBound_0 int = 3;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @__lowerBound_0 AND [e].[Id] <= 10

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedIntField_UsedInProjectableMethod.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @__lowerBound_0 int = 3;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @__lowerBound_0 AND [e].[Id] <= 10

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMixedFields_IntAndIQueryable_BothResolvedCorrectly.DotNet10_0.verified.txt

@@ -0,0 +1,8 @@
+DECLARE @minCount int = 1;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE ([e].[Id] >= @minCount AND [e].[Id] <= 50) OR EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 10 AND [e0].[Id] <= 100 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMixedFields_IntAndIQueryable_BothResolvedCorrectly.DotNet9_0.verified.txt

@@ -0,0 +1,8 @@
+DECLARE @__minCount_0 int = 1;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE ([e].[Id] >= @__minCount_0 AND [e].[Id] <= 50) OR EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 10 AND [e0].[Id] <= 100 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMixedFields_IntAndIQueryable_BothResolvedCorrectly.verified.txt

@@ -0,0 +1,8 @@
+DECLARE @__minCount_0 int = 1;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE ([e].[Id] >= @__minCount_0 AND [e].[Id] <= 50) OR EXISTS (
+    SELECT 1
+    FROM [Entity] AS [e0]
+    WHERE [e0].[Id] >= 10 AND [e0].[Id] <= 100 AND [e0].[Id] = [e].[Id])

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMultipleIntFields_UsedInProjectableMethod.DotNet10_0.verified.txt

@@ -0,0 +1,6 @@
+DECLARE @lower int = 2;
+DECLARE @upper int = 8;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @lower AND [e].[Id] <= @upper

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMultipleIntFields_UsedInProjectableMethod.DotNet9_0.verified.txt

@@ -0,0 +1,6 @@
+DECLARE @__lower_0 int = 2;
+DECLARE @__upper_1 int = 8;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @__lower_0 AND [e].[Id] <= @__upper_1

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedMultipleIntFields_UsedInProjectableMethod.verified.txt

@@ -0,0 +1,6 @@
+DECLARE @__lower_0 int = 2;
+DECLARE @__upper_1 int = 8;
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Id] >= @__lower_0 AND [e].[Id] <= @__upper_1

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedStringField_UsedInProjectableMethod.DotNet10_0.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @targetName nvarchar(4000) = N'Alice';
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Name] = @targetName

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedStringField_UsedInProjectableMethod.DotNet9_0.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @__targetName_0 nvarchar(4000) = N'Alice';
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Name] = @__targetName_0

tests/EntityFrameworkCore.Projectables.FunctionalTests/ClosureMemberAccessTests.CapturedStringField_UsedInProjectableMethod.verified.txt

@@ -0,0 +1,5 @@
+DECLARE @__targetName_0 nvarchar(4000) = N'Alice';
+
+SELECT [e].[Id], [e].[Name]
+FROM [Entity] AS [e]
+WHERE [e].[Name] = @__targetName_0