Fix to #21607 - Incorrect results returned when joining a key-less vi…

…ew to an entity

Disabling the scenario when we try to add collection join to keyless entity parent, since we don't have identifying columns to properly bucket the results.

Fixes #21607

src/EFCore.Relational/Properties/RelationalStrings.resx

@@ -700,6 +700,9 @@
   <data name="SequenceContainsNoElements" xml:space="preserve">
     <value>Sequence contains no elements.</value>
   </data>
+  <data name="ProjectingCollectionOnKeylessEntityNotSupported" xml:space="preserve">
+    <value>Projecting collection associated with keyless entity is not supported.</value>
+  </data>
   <data name="LogBatchExecutorFailedToRollbackToSavepoint" xml:space="preserve">
     <value>An error occurred while the batch executor was rolling back the transaction to a savepoint, after an exception occured.</value>
     <comment>Debug RelationalEventId.BatchExecutorFailedToRollbackToSavepoint</comment>

src/EFCore.Relational/Query/SqlExpressions/SelectExpression.cs

@@ -1415,6 +1415,11 @@ public Expression ApplyCollectionJoin(
             else
             {
                 var parentIdentifierList = _identifier.Except(_childIdentifiers).ToList();
+                if (parentIdentifierList.Count == 0)
+                {
+                    throw new NotSupportedException(RelationalStrings.ProjectingCollectionOnKeylessEntityNotSupported);
+                }
+
                 var (parentIdentifier, parentIdentifierValueComparers) = GetIdentifierAccessor(parentIdentifierList);
                 var (outerIdentifier, outerIdentifierValueComparers) = GetIdentifierAccessor(_identifier);
                 var innerClientEval = innerSelectExpression.Projection.Count > 0;

test/EFCore.Cosmos.FunctionalTests/Query/NorthwindKeylessEntitiesQueryCosmosTest.cs

@@ -137,6 +137,14 @@ public override async Task KeylesEntity_groupby(bool async)
             AssertSql(@"");
         }
 
+        [ConditionalFact(Skip = "Issue #20441")]
+        public override void Collection_correlated_with_keyless_entity_in_predicate_works()
+        {
+            base.Collection_correlated_with_keyless_entity_in_predicate_works();
+
+            AssertSql(@"");
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
 

test/EFCore.Relational.Specification.Tests/Query/NorthwindKeylessEntitiesQueryRelationalTestBase.cs

@@ -1,7 +1,13 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.EntityFrameworkCore.TestModels.Northwind;
 using Microsoft.EntityFrameworkCore.TestUtilities;
+using Xunit;
 
 namespace Microsoft.EntityFrameworkCore.Query
 {
@@ -15,6 +21,20 @@ protected NorthwindKeylessEntitiesQueryRelationalTestBase(TFixture fixture)
 
         protected virtual bool CanExecuteQueryString => false;
 
+        [ConditionalFact]
+        public virtual void Projecting_collection_correlated_with_keyless_entity_throws()
+        {
+            using var context = CreateContext();
+            var message = Assert.Throws<NotSupportedException>(() => context.Set<ProductQuery>().Select(pv => new
+            {
+                pv.ProductID,
+                pv.ProductName,
+                OrderDetailIds = context.Set<OrderDetail>().Where(od => od.ProductID == pv.ProductID).ToList()
+            }).OrderBy(x => x.ProductID).Take(2).ToList()).Message;
+
+            Assert.Equal(RelationalStrings.ProjectingCollectionOnKeylessEntityNotSupported, message);
+        }
+
         protected override QueryAsserter CreateQueryAsserter(TFixture fixture)
             => new RelationalQueryAsserter(fixture, RewriteExpectedQueryExpression, RewriteServerQueryExpression, canExecuteQueryString: CanExecuteQueryString);
     }

test/EFCore.Specification.Tests/Query/NorthwindKeylessEntitiesQueryTestBase.cs

@@ -199,5 +199,20 @@ from pv in grouping.DefaultIfEmpty()
 
             Assert.Equal(830, results.Count);
         }
+
+        [ConditionalFact]
+        public virtual void Collection_correlated_with_keyless_entity_in_predicate_works()
+        {
+            using var context = CreateContext();
+
+            var results = context.Set<ProductQuery>()
+                .Where(pv => context.Set<OrderDetail>().Where(od => od.ProductID == pv.ProductID).Any())
+                .Select(pv => new { pv.ProductID, pv.ProductName })
+                .OrderBy(x => x.ProductID)
+                .Take(2)
+                .ToList();
+
+            Assert.Equal(2, results.Count);
+        }
     }
 }

test/EFCore.SqlServer.FunctionalTests/Query/NorthwindKeylessEntitiesQuerySqlServerTest.cs

@@ -168,6 +168,22 @@ FROM [Orders] AS [o]
 LEFT JOIN [Alphabetical list of products] AS [a] ON [o].[CustomerID] = [a].[CategoryName]");
         }
 
+        public override void Collection_correlated_with_keyless_entity_in_predicate_works()
+        {
+            base.Collection_correlated_with_keyless_entity_in_predicate_works();
+
+            AssertSql(
+                @"@__p_0='2'
+
+SELECT TOP(@__p_0) [p].[ProductID], [p].[ProductName]
+FROM [Products] AS [p]
+WHERE ([p].[Discontinued] <> CAST(1 AS bit)) AND EXISTS (
+    SELECT 1
+    FROM [Order Details] AS [o]
+    WHERE [o].[ProductID] = [p].[ProductID])
+ORDER BY [p].[ProductID]");
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);