Overwrite pre-initialized reference navigations when querying

src/EFCore/ChangeTracking/Internal/NavigationFixer.cs

@@ -701,6 +701,7 @@ private void InitialFixup(
                     var navigation = foreignKey.DependentToPrincipal;
                     var existingPrincipal = navigation == null ? null : entry[navigation];
                     if (existingPrincipal == null
+                        || fromQuery
                         || existingPrincipal == principalEntry.Entity)
                     {
                         // Set navigation to principal based on FK properties
@@ -724,7 +725,8 @@ private void InitialFixup(
                         var dependentEntry = (InternalEntityEntry?)dependents.FirstOrDefault();
                         if (dependentEntry != null)
                         {
-                            if ((!foreignKey.IsOwnership
+                            if (fromQuery
+                                || (!foreignKey.IsOwnership
                                     || (dependentEntry.EntityState != EntityState.Deleted
                                         && dependentEntry.EntityState != EntityState.Detached))
                                 && (foreignKey.PrincipalToDependent == null
@@ -741,12 +743,9 @@ private void InitialFixup(
                     {
                         foreach (InternalEntityEntry dependentEntry in dependents)
                         {
-                            if ((!foreignKey.IsOwnership
-                                    || (dependentEntry.EntityState != EntityState.Deleted
-                                        && dependentEntry.EntityState != EntityState.Detached))
-                                && (!fromQuery
-                                    || foreignKey.DependentToPrincipal == null
-                                    || dependentEntry.GetCurrentValue(foreignKey.DependentToPrincipal) == null))
+                            if (!foreignKey.IsOwnership
+                                || (dependentEntry.EntityState != EntityState.Deleted
+                                    && dependentEntry.EntityState != EntityState.Detached))
                             {
                                 // Add to collection on principal indicated by FK and set inverse navigation
                                 AddToCollection(entry, foreignKey.PrincipalToDependent, dependentEntry, fromQuery);

test/EFCore.Cosmos.FunctionalTests/OverzealousInitializationCosmosTest.cs

@@ -15,7 +15,7 @@ public OverzealousInitializationCosmosTest(OverzealousInitializationCosmosFixtur
         }
 
         [ConditionalFact(Skip = "Issue #17246")]
-        public override void Fixup_does_not_ignore_eagerly_initialized_reference_navs()
+        public override void Fixup_ignores_eagerly_initialized_reference_navs()
         {
         }
 

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

@@ -50,7 +50,7 @@ public override async Task Include_collection_dependent_already_tracked(bool asy
             using var context = CreateContext();
             var orders = context.Set<Order>().Where(o => o.CustomerID == "ALFKI").ToList();
             Assert.Equal(6, context.ChangeTracker.Entries().Count());
-            Assert.True(orders.All(o => o.Customer == null));
+            Assert.True(orders.All(o => o.Customer.CustomerID == null));
 
             var customer
                 = async
@@ -70,7 +70,7 @@ var customer
             Assert.True(customer.Orders.All(e => ReferenceEquals(e.Customer, customer)));
 
             Assert.Equal(6, context.ChangeTracker.Entries().Count());
-            Assert.True(orders.All(o => o.Customer == null));
+            Assert.True(orders.All(o => o.Customer.CustomerID == null));
         }
 
         public override async Task Include_collection_principal_already_tracked(bool async)

test/EFCore.Specification.Tests/OverzealousInitializationTestBase.cs

@@ -17,23 +17,33 @@ protected OverzealousInitializationTestBase(TFixture fixture)
             => Fixture = fixture;
 
         [ConditionalFact]
-        public virtual void Fixup_does_not_ignore_eagerly_initialized_reference_navs()
+        public virtual void Fixup_ignores_eagerly_initialized_reference_navs()
         {
             using var context = CreateContext();
 
             var albums = context.Set<Album>()
                 .Include(e => e.Tracks)
                 .Include(e => e.Artist)
-                .OrderBy(e => e.Artist)
+                .OrderBy(e => e.Id)
                 .ToList();
 
+            var i = 0;
             foreach (var album in albums)
             {
-                Assert.Equal(0, album.Artist.Id);
-                Assert.Null(album.Artist.Name);
+                var artist = _artists[i++ % 3];
+
+                Assert.Equal(artist.Id, album.Artist.Id);
+                Assert.Equal(artist.Name, album.Artist.Name);
             }
         }
 
+        private static readonly Artist[] _artists = new[]
+        {
+            new Artist { Id = 1, Name = "Freddie" },
+            new Artist { Id = 2, Name = "Kendrick" },
+            new Artist { Id = 3, Name = "Jarvis" }
+        };
+
         protected class Album
         {
             [DatabaseGenerated(DatabaseGeneratedOption.None)]
@@ -96,20 +106,13 @@ public virtual IDisposable BeginTransaction(DbContext context)
 
             protected override void Seed(AlbumViewerContext context)
             {
-                var artists = new[]
-                {
-                    new Artist { Id = 1, Name = "Freddie" },
-                    new Artist { Id = 2, Name = "Kendrick" },
-                    new Artist { Id = 3, Name = "Jarvis" }
-                };
-
                 for (var i = 1; i <= 10; i++)
                 {
                     context.Add(
                         new Album
                         {
                             Id = i,
-                            Artist = artists[i % 3],
+                            Artist = _artists[(i - 1) % 3],
                             Tracks = new List<Track> { new() { Id = i * 2 }, new() { Id = i * 2 + 1 } }
                         });
                 }

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

@@ -148,7 +148,7 @@ public override async Task Include_collection_dependent_already_tracked(bool asy
             using var context = CreateContext();
             var orders = context.Set<Order>().Where(o => o.CustomerID == "ALFKI").ToList();
             Assert.Equal(6, context.ChangeTracker.Entries().Count());
-            Assert.True(orders.All(o => o.Customer == null));
+            Assert.True(orders.All(o => o.Customer.CustomerID == null));
 
             var customer
                 = async
@@ -166,7 +166,7 @@ var customer
             Assert.True(customer.Orders.All(e => ReferenceEquals(e.Customer, customer)));
 
             Assert.Equal(6, context.ChangeTracker.Entries().Count());
-            Assert.True(orders.All(o => o.Customer == null));
+            Assert.True(orders.All(o => o.Customer.CustomerID == null));
         }
 
         public override async Task Include_collection_principal_already_tracked(bool async)

test/EFCore.Specification.Tests/TestModels/GearsOfWarModel/Gear.cs

@@ -27,7 +27,7 @@ public Gear()
 
         public MilitaryRank Rank { get; set; }
 
-        public virtual CogTag Tag { get; set; }
+        public virtual CogTag Tag { get; set; } = new(); // Initialized to test #23851
 
         public virtual Squad Squad { get; set; }