[release/11.0] Fix projecting JSON complex collection together with collection navigation

src/EFCore.Relational/Query/Internal/RelationalProjectionBindingExpressionVisitor.cs

@@ -557,11 +557,12 @@ protected override Expression VisitExtension(Expression extensionExpression)
                 if (_indexBasedBinding)
                 {
                     _clientProjections!.Add(jsonQuery);
+
+                    return collectionResult.Update(
+                        new ProjectionBindingExpression(_selectExpression, _clientProjections.Count - 1, collectionResult.Type));
                 }
-                else
-                {
-                    _projectionMapping[_projectionMembers.Peek()] = jsonQuery;
-                }
+
+                _projectionMapping[_projectionMembers.Peek()] = jsonQuery;
 
                 return collectionResult.Update(
                     new ProjectionBindingExpression(_selectExpression, _projectionMembers.Peek(), collectionResult.Type));

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

@@ -296,6 +296,75 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
 
     #endregion 38077
 
+    #region 38928
+
+    [Fact]
+    public virtual async Task Project_json_complex_collection_together_with_collection_navigation()
+    {
+        var contextFactory = await InitializeNonSharedTest<Context38928>(
+            seed: async context =>
+            {
+                context.Set<Context38928.Parent>().Add(
+                    new Context38928.Parent
+                    {
+                        Items = [new Context38928.ChildItem { Value = "/x" }],
+                        Links = [new Context38928.Link()]
+                    });
+
+                await context.SaveChangesAsync();
+            });
+
+        await using var context = contextFactory.CreateDbContext();
+
+        var result = await context.Set<Context38928.Parent>()
+            .AsSplitQuery()
+            .Select(p => new
+            {
+                p.Id,
+                p.Items,
+                Links = p.Links.Select(l => new { l.Id }).ToList()
+            })
+            .SingleAsync();
+
+        Assert.NotEqual(0, result.Id);
+        Assert.NotNull(result.Items);
+        var item = Assert.Single(result.Items);
+        Assert.Equal("/x", item.Value);
+        Assert.Single(result.Links);
+    }
+
+    private class Context38928(DbContextOptions options) : DbContext(options)
+    {
+        public class Parent
+        {
+            public int Id { get; set; }
+            public List<ChildItem>? Items { get; set; }
+            public List<Link> Links { get; set; } = [];
+        }
+
+        public class ChildItem
+        {
+            public required string Value { get; init; }
+        }
+
+        public class Link
+        {
+            public int Id { get; set; }
+            public List<Parent> Parents { get; set; } = [];
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<Parent>(b =>
+            {
+                b.ComplexCollection(p => p.Items).ToJson();
+                b.HasMany(p => p.Links).WithMany(l => l.Parents).UsingEntity("ParentLinks");
+            });
+        }
+    }
+
+    #endregion 38928
+
     protected TestSqlLoggerFactory TestSqlLoggerFactory
         => (TestSqlLoggerFactory)ListLoggerFactory;
 

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

@@ -1624,6 +1624,33 @@ FROM [Child] AS [c]
 """);
     }
 
+    public override async Task Project_json_complex_collection_together_with_collection_navigation()
+    {
+        await base.Project_json_complex_collection_together_with_collection_navigation();
+
+        AssertSql(
+            """
+SELECT TOP(2) [p].[Id], [p].[Items]
+FROM [Parent] AS [p]
+ORDER BY [p].[Id]
+""",
+            //
+            """
+SELECT [s].[Id], [p3].[Id]
+FROM (
+    SELECT TOP(1) [p].[Id]
+    FROM [Parent] AS [p]
+    ORDER BY [p].[Id]
+) AS [p3]
+INNER JOIN (
+    SELECT [l1].[Id], [p2].[ParentsId]
+    FROM [ParentLinks] AS [p2]
+    INNER JOIN [Link] AS [l1] ON [p2].[LinksId] = [l1].[Id]
+) AS [s] ON [p3].[Id] = [s].[ParentsId]
+ORDER BY [p3].[Id]
+""");
+    }
+
     #endregion Non-shared test resources
 
     [Fact]

test/EFCore.Sqlite.FunctionalTests/Query/ComplexTypeQuerySqliteTest.cs

@@ -1454,6 +1454,35 @@ public override async Task Complex_property_on_split_entity()
 """);
     }
 
+    public override async Task Project_json_complex_collection_together_with_collection_navigation()
+    {
+        await base.Project_json_complex_collection_together_with_collection_navigation();
+
+        AssertSql(
+            """
+SELECT "p"."Id", "p"."Items"
+FROM "Parent" AS "p"
+ORDER BY "p"."Id"
+LIMIT 2
+""",
+            //
+            """
+SELECT "s"."Id", "p3"."Id"
+FROM (
+    SELECT "p"."Id"
+    FROM "Parent" AS "p"
+    ORDER BY "p"."Id"
+    LIMIT 1
+) AS "p3"
+INNER JOIN (
+    SELECT "l1"."Id", "p2"."ParentsId"
+    FROM "ParentLinks" AS "p2"
+    INNER JOIN "Link" AS "l1" ON "p2"."LinksId" = "l1"."Id"
+) AS "s" ON "p3"."Id" = "s"."ParentsId"
+ORDER BY "p3"."Id"
+""");
+    }
+
     #endregion Non-shared test resources
 
     [Fact]