Fix to #16231 - Query: Include on client projection gets ignored

Problem was that when we search and apply include on the final projection we short circuit when we encounter member access. However, we should only do that if the member access is on top of navigation binding - in other cases, like client-side functions, we should peek inside and potentially apply includes on entities that are defined there.

src/EFCore/Query/NavigationExpansion/Visitors/IncludeApplyingVisitor.cs

@@ -9,7 +9,20 @@ namespace Microsoft.EntityFrameworkCore.Query.NavigationExpansion.Visitors
 {
     public class PendingSelectorIncludeRewriter : ExpressionVisitor
     {
-        protected override Expression VisitMember(MemberExpression memberExpression) => memberExpression;
+        protected override Expression VisitMember(MemberExpression memberExpression)
+        {
+            if (memberExpression.Expression is NavigationBindingExpression)
+            {
+                return memberExpression;
+            }
+
+            var newExpression = Visit(memberExpression.Expression);
+
+            return newExpression != memberExpression.Expression
+                ? Expression.MakeMemberAccess(newExpression, memberExpression.Member)
+                : memberExpression;
+        }
+
         protected override Expression VisitInvocation(InvocationExpression invocationExpression) => invocationExpression;
         protected override Expression VisitLambda<T>(Expression<T> lambdaExpression) => lambdaExpression;
         protected override Expression VisitTypeBinary(TypeBinaryExpression typeBinaryExpression) => typeBinaryExpression;

src/EFCore/Query/NavigationExpansion/Visitors/PendingIncludeFindingVisitor.cs

@@ -12,7 +12,18 @@ public class PendingIncludeFindingVisitor : ExpressionVisitor
     {
         public virtual Dictionary<NavigationTreeNode, SourceMapping> PendingIncludes { get; } = new Dictionary<NavigationTreeNode, SourceMapping>();
 
-        protected override Expression VisitMember(MemberExpression memberExpression) => memberExpression;
+        protected override Expression VisitMember(MemberExpression memberExpression)
+        {
+            if (memberExpression.Expression is NavigationBindingExpression)
+            {
+                return memberExpression;
+            }
+
+            Visit(memberExpression.Expression);
+
+            return memberExpression;
+        }
+
         protected override Expression VisitInvocation(InvocationExpression invocationExpression) => invocationExpression;
         protected override Expression VisitLambda<T>(Expression<T> lambdaExpression) => lambdaExpression;
         protected override Expression VisitTypeBinary(TypeBinaryExpression typeBinaryExpression) => typeBinaryExpression;

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

@@ -7182,6 +7182,19 @@ public virtual Task Include_collection_with_Cast_to_base(bool isAsync)
                 new List<IExpectedInclude> { new ExpectedInclude<Gear>(e => e.Weapons, "Weapons") });
         }
 
+        [ConditionalFact]
+        public virtual void Include_with_client_method_and_member_access_still_applies_includes()
+        {
+            using (var ctx = CreateContext())
+            {
+                var query = ctx.Gears
+                    .Include(g => g.Tag)
+                    .Select(g => new { g.Nickname, Client(g).FullName });
+
+                var result = query.ToList();
+            }
+        }
+
         [ConditionalFact(Skip = "Issue #15611")]
         public virtual Task Multiple_includes_with_client_method_around_qsre_and_also_projecting_included_collection()
         {

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

@@ -8208,6 +8208,17 @@ FROM [Gears] AS [g0]
 ORDER BY [t].[FullName]");
         }
 
+        public override void Include_with_client_method_and_member_access_still_applies_includes()
+        {
+            base.Include_with_client_method_and_member_access_still_applies_includes();
+
+            AssertSql(
+                @"SELECT [g].[Nickname], [g].[SquadId], [g].[AssignedCityName], [g].[CityOrBirthName], [g].[Discriminator], [g].[FullName], [g].[HasSoulPatch], [g].[LeaderNickname], [g].[LeaderSquadId], [g].[Rank], [t].[Id], [t].[GearNickName], [t].[GearSquadId], [t].[Note]
+FROM [Gears] AS [g]
+LEFT JOIN [Tags] AS [t] ON (([g].[Nickname] = [t].[GearNickName]) AND [t].[GearNickName] IS NOT NULL) AND (([g].[SquadId] = [t].[GearSquadId]) AND [t].[GearSquadId] IS NOT NULL)
+WHERE [g].[Discriminator] IN (N'Gear', N'Officer')");
+        }
+
         public override async Task Multiple_includes_with_client_method_around_qsre_and_also_projecting_included_collection()
         {
             await base.Multiple_includes_with_client_method_around_qsre_and_also_projecting_included_collection();