Query: API review changes

Part of #27588

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

@@ -600,7 +600,6 @@ public virtual GroupByShaperExpression ApplyGrouping(
 
         return new GroupByShaperExpression(
             groupingKey,
-            shaperExpression,
             new ShapedQueryExpression(
                 clonedInMemoryQueryExpression,
                 new QueryExpressionReplacingExpressionVisitor(this, clonedInMemoryQueryExpression).Visit(shaperExpression)));

src/EFCore.Relational/Query/EnumerableExpression.cs

@@ -2,8 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Runtime.CompilerServices;
+using Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 
-namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
+namespace Microsoft.EntityFrameworkCore.Query;
 
 /// <summary>
 ///     <para>
@@ -16,96 +17,122 @@ namespace Microsoft.EntityFrameworkCore.Query.SqlExpressions;
 /// </summary>
 public class EnumerableExpression : Expression, IPrintableExpression
 {
-    private readonly List<OrderingExpression> _orderings = new();
-
     /// <summary>
     ///     Creates a new instance of the <see cref="EnumerableExpression" /> class.
     /// </summary>
     /// <param name="selector">The underlying sql expression being enumerated.</param>
     public EnumerableExpression(Expression selector)
     {
         Selector = selector;
+        IsDistinct = false;
+        Predicate = null;
+        Orderings = new List<OrderingExpression>();
+    }
+
+    private EnumerableExpression(
+        Expression selector,
+        bool distinct,
+        SqlExpression? predicate,
+        IReadOnlyList<OrderingExpression> orderings)
+    {
+        Selector = selector;
+        IsDistinct = distinct;
+        Predicate = predicate;
+        Orderings = orderings;
     }
 
     /// <summary>
     ///     The underlying expression being enumerated.
     /// </summary>
-    public virtual Expression Selector { get; private set; }
+    public virtual Expression Selector { get; }
 
     /// <summary>
     ///     The value indicating if distinct operator is applied on the enumerable or not.
     /// </summary>
-    public virtual bool IsDistinct { get; private set; }
+    public virtual bool IsDistinct { get; }
 
     /// <summary>
     ///     The value indicating any predicate applied on the enumerable.
     /// </summary>
-    public virtual SqlExpression? Predicate { get; private set;  }
+    public virtual SqlExpression? Predicate { get; }
 
     /// <summary>
     ///     The list of orderings to be applied to the enumerable.
     /// </summary>
-    public virtual IReadOnlyList<OrderingExpression> Orderings => _orderings;
+    public virtual IReadOnlyList<OrderingExpression> Orderings { get; }
 
 
     /// <summary>
     ///     Applies new selector to the <see cref="EnumerableExpression" />.
     /// </summary>
-    public virtual void ApplySelector(Expression expression)
-    {
-        Selector = expression;
-    }
+    /// <returns>The new expression with specified component updated.</returns>
+    public virtual EnumerableExpression ApplySelector(Expression expression)
+        => new(expression, IsDistinct, Predicate, Orderings);
 
     /// <summary>
     ///     Applies DISTINCT operator to the selector of the <see cref="EnumerableExpression" />.
     /// </summary>
-    public virtual void ApplyDistinct()
-    {
-        IsDistinct = true;
-    }
+    /// <returns>The new expression with specified component updated.</returns>
+    public virtual EnumerableExpression ApplyDistinct()
+        => new(Selector, distinct: true, Predicate, Orderings);
 
     /// <summary>
     ///     Applies filter predicate to the <see cref="EnumerableExpression" />.
     /// </summary>
     /// <param name="sqlExpression">An expression to use for filtering.</param>
-    public virtual void ApplyPredicate(SqlExpression sqlExpression)
+    /// <returns>The new expression with specified component updated.</returns>
+    public virtual EnumerableExpression ApplyPredicate(SqlExpression sqlExpression)
     {
         if (sqlExpression is SqlConstantExpression sqlConstant
             && sqlConstant.Value is bool boolValue
             && boolValue)
         {
-            return;
+            return this;
         }
 
-        Predicate = Predicate == null
+        var predicate = Predicate == null
             ? sqlExpression
             : new SqlBinaryExpression(
                 ExpressionType.AndAlso,
                 Predicate,
                 sqlExpression,
                 typeof(bool),
                 sqlExpression.TypeMapping);
+
+        return new(Selector, IsDistinct, predicate, Orderings);
     }
 
     /// <summary>
     ///     Applies ordering to the <see cref="EnumerableExpression" />. This overwrites any previous ordering specified.
     /// </summary>
     /// <param name="orderingExpression">An ordering expression to use for ordering.</param>
-    public virtual void ApplyOrdering(OrderingExpression orderingExpression)
+    /// <returns>The new expression with specified component updated.</returns>
+    public virtual EnumerableExpression ApplyOrdering(OrderingExpression orderingExpression)
     {
-        _orderings.Clear();
-        AppendOrdering(orderingExpression);
+        var orderings = new List<OrderingExpression>();
+        AppendOrdering(orderings, orderingExpression);
+
+        return new EnumerableExpression(Selector, IsDistinct, Predicate, orderings);
     }
 
     /// <summary>
     ///     Appends ordering to the existing orderings of the <see cref="EnumerableExpression" />.
     /// </summary>
     /// <param name="orderingExpression">An ordering expression to use for ordering.</param>
-    public virtual void AppendOrdering(OrderingExpression orderingExpression)
+    /// <returns>The new expression with specified component updated.</returns>
+    public virtual EnumerableExpression AppendOrdering(OrderingExpression orderingExpression)
+    {
+        var orderings = Orderings.ToList();
+        AppendOrdering(orderings, orderingExpression);
+
+        return new EnumerableExpression(Selector, IsDistinct, Predicate, orderings);
+    }
+
+    private static void AppendOrdering(List<OrderingExpression> orderings, OrderingExpression orderingExpression)
     {
-        if (!_orderings.Any(o => o.Expression.Equals(orderingExpression.Expression)))
+        if (!orderings.Any(o => o.Expression.Equals(orderingExpression.Expression)))
         {
-            _orderings.Add(orderingExpression.Update(orderingExpression.Expression));
+            orderings.Add(orderingExpression.Update(orderingExpression.Expression));
         }
     }
 
@@ -151,8 +178,32 @@ public virtual void Print(ExpressionPrinter expressionPrinter)
     }
 
     /// <inheritdoc />
-    public override bool Equals(object? obj) => ReferenceEquals(this, obj);
+    public override bool Equals(object? obj)
+        => obj != null
+            && (ReferenceEquals(this, obj)
+                || obj is EnumerableExpression enumerableExpression
+                && Equals(enumerableExpression));
+
+    private bool Equals(EnumerableExpression enumerableExpression)
+        => IsDistinct == enumerableExpression.IsDistinct
+        && (Predicate == null
+            ? enumerableExpression.Predicate == null
+            : Predicate.Equals(enumerableExpression.Predicate))
+        && ExpressionEqualityComparer.Instance.Equals(Selector, enumerableExpression.Selector)
+        && Orderings.SequenceEqual(enumerableExpression.Orderings);
 
     /// <inheritdoc />
-    public override int GetHashCode() => RuntimeHelpers.GetHashCode(this);
+    public override int GetHashCode()
+    {
+        var hashCode = new HashCode();
+        hashCode.Add(IsDistinct);
+        hashCode.Add(Selector);
+        hashCode.Add(Predicate);
+        foreach (var ordering in Orderings)
+        {
+            hashCode.Add(ordering);
+        }
+
+        return hashCode.ToHashCode();
+    }
 }

src/EFCore.Relational/Query/RelationalGroupByShaperExpression.cs

@@ -0,0 +1,57 @@
+// 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.Query;
+
+/// <summary>
+///     <para>
+///         An expression that represents creation of a grouping element in <see cref="ShapedQueryExpression.ShaperExpression" />
+///         for relational providers.
+///     </para>
+///     <para>
+///         This type is typically used by database providers (and other extensions). It is generally
+///         not used in application code.
+///     </para>
+/// </summary>
+public class RelationalGroupByShaperExpression : GroupByShaperExpression
+{
+    /// <summary>
+    ///     Creates a new instance of the <see cref="RelationalGroupByShaperExpression" /> class.
+    /// </summary>
+    /// <param name="keySelector">An expression representing key selector for the grouping result.</param>
+    /// <param name="elementSelector">An expression representing element selector for the grouping result.</param>
+    /// <param name="groupingEnumerable">An expression representing subquery for enumerable over the grouping result.</param>
+    public RelationalGroupByShaperExpression(
+        Expression keySelector,
+        Expression elementSelector,
+        ShapedQueryExpression groupingEnumerable)
+        : base(keySelector, groupingEnumerable)
+    {
+        ElementSelector = elementSelector;
+    }
+
+    /// <summary>
+    ///     The expression representing the element selector for this grouping result.
+    /// </summary>
+    public virtual Expression ElementSelector { get; }
+
+    /// <inheritdoc />
+    protected override Expression VisitChildren(ExpressionVisitor visitor)
+        => throw new InvalidOperationException(
+            CoreStrings.VisitIsNotAllowed($"{nameof(RelationalGroupByShaperExpression)}.{nameof(VisitChildren)}"));
+
+    /// <inheritdoc />
+    public override void Print(ExpressionPrinter expressionPrinter)
+    {
+        expressionPrinter.AppendLine($"{nameof(RelationalGroupByShaperExpression)}:");
+        expressionPrinter.Append("KeySelector: ");
+        expressionPrinter.Visit(KeySelector);
+        expressionPrinter.AppendLine(", ");
+        expressionPrinter.Append("ElementSelector: ");
+        expressionPrinter.Visit(ElementSelector);
+        expressionPrinter.AppendLine(", ");
+        expressionPrinter.Append("GroupingEnumerable:");
+        expressionPrinter.Visit(GroupingEnumerable);
+        expressionPrinter.AppendLine();
+    }
+}