[5.0] Fix places where skip navigations are missed

src/EFCore/ChangeTracking/EntityEntry.cs

@@ -203,10 +203,18 @@ public virtual NavigationEntry Navigation([NotNull] string propertyName)
         ///     navigation properties of this entity.
         /// </summary>
         public virtual IEnumerable<NavigationEntry> Navigations
-            => InternalEntry.EntityType.GetNavigations().Select(
-                navigation => navigation.IsCollection
-                    ? (NavigationEntry)new CollectionEntry(InternalEntry, navigation)
-                    : new ReferenceEntry(InternalEntry, navigation));
+        {
+            get
+            {
+                var entityType = InternalEntry.EntityType;
+                return entityType.GetNavigations()
+                    .Concat<INavigationBase>(entityType.GetSkipNavigations())
+                    .Select(
+                        navigation => navigation.IsCollection
+                            ? (NavigationEntry)new CollectionEntry(InternalEntry, navigation.Name)
+                            : new ReferenceEntry(InternalEntry, navigation.Name));
+            }
+        }
 
         /// <summary>
         ///     Provides access to change tracking information and operations for a given
@@ -273,8 +281,16 @@ public virtual CollectionEntry Collection([NotNull] string propertyName)
         ///     collection navigation properties of this entity.
         /// </summary>
         public virtual IEnumerable<CollectionEntry> Collections
-            => InternalEntry.EntityType.GetNavigations().Where(n => n.IsCollection)
-                .Select(navigation => new CollectionEntry(InternalEntry, navigation));
+        {
+            get
+            {
+                var entityType = InternalEntry.EntityType;
+                return entityType.GetNavigations()
+                    .Concat<INavigationBase>(entityType.GetSkipNavigations())
+                    .Where(navigation => navigation.IsCollection)
+                    .Select(navigation => new CollectionEntry(InternalEntry, navigation.Name));
+            }
+        }
 
         /// <summary>
         ///     <para>

src/EFCore/ChangeTracking/Internal/EntityEntryGraphIterator.cs

@@ -93,7 +93,8 @@ public virtual async Task TraverseGraphAsync<TState>(
             }
 
             var internalEntityEntry = node.GetInfrastructure();
-            var navigations = internalEntityEntry.EntityType.GetNavigations();
+            var navigations = internalEntityEntry.EntityType.GetNavigations()
+                .Concat<INavigationBase>(internalEntityEntry.EntityType.GetSkipNavigations());
             var stateManager = internalEntityEntry.StateManager;
 
             foreach (var navigation in navigations)

src/EFCore/ChangeTracking/Internal/InternalEntityEntrySubscriber.cs

@@ -85,7 +85,9 @@ public virtual void Unsubscribe(InternalEntityEntry entry)
 
             if (changeTrackingStrategy != ChangeTrackingStrategy.Snapshot)
             {
-                foreach (var navigation in entityType.GetNavigations().Where(n => n.IsCollection))
+                foreach (var navigation in entityType.GetNavigations()
+                    .Concat<INavigationBase>(entityType.GetSkipNavigations())
+                    .Where(n => n.IsCollection))
                 {
                     AsINotifyCollectionChanged(entry, navigation, entityType, changeTrackingStrategy).CollectionChanged
                         -= entry.HandleINotifyCollectionChanged;

src/EFCore/Extensions/EntityTypeExtensions.cs

@@ -634,7 +634,8 @@ public static IProperty GetProperty([NotNull] this IEntityType entityType, [NotN
             var property = entityType.FindProperty(name);
             if (property == null)
             {
-                if (entityType.FindNavigation(name) != null)
+                if (entityType.FindNavigation(name) != null
+                    || entityType.FindSkipNavigation(name) != null)
                 {
                     throw new InvalidOperationException(
                         CoreStrings.PropertyIsNavigation(

src/EFCore/Metadata/Internal/EntityTypeExtensions.cs

@@ -419,12 +419,19 @@ public static IEnumerable<IPropertyBase> GetNotificationProperties(
                 {
                     yield return navigation;
                 }
+
+                foreach (var navigation in entityType.GetSkipNavigations())
+                {
+                    yield return navigation;
+                }
             }
             else
             {
                 // ReSharper disable once AssignNullToNotNullAttribute
-                var property = (IPropertyBase)entityType.FindProperty(propertyName)
-                    ?? entityType.FindNavigation(propertyName);
+                var property = entityType.FindProperty(propertyName)
+                    ?? entityType.FindNavigation(propertyName)
+                    ?? (IPropertyBase)entityType.FindSkipNavigation(propertyName);
+
                 if (property != null)
                 {
                     yield return property;

test/EFCore.InMemory.FunctionalTests/ManyToManyTrackingInMemoryTest.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.EntityFrameworkCore.TestModels.ManyToManyModel;
 using Microsoft.EntityFrameworkCore.TestUtilities;
@@ -22,10 +23,24 @@ protected override void ExecuteWithStrategyInTransaction(
             Action<ManyToManyContext> nestedTestOperation2 = null,
             Action<ManyToManyContext> nestedTestOperation3 = null)
         {
-            base.ExecuteWithStrategyInTransaction(testOperation, nestedTestOperation1, nestedTestOperation2, nestedTestOperation3);
+            base.ExecuteWithStrategyInTransaction(
+                testOperation, nestedTestOperation1, nestedTestOperation2, nestedTestOperation3);
+
             Fixture.Reseed();
         }
 
+        protected override async Task ExecuteWithStrategyInTransactionAsync(
+            Func<ManyToManyContext, Task> testOperation,
+            Func<ManyToManyContext, Task> nestedTestOperation1 = null,
+            Func<ManyToManyContext, Task> nestedTestOperation2 = null,
+            Func<ManyToManyContext, Task> nestedTestOperation3 = null)
+        {
+            await base.ExecuteWithStrategyInTransactionAsync(
+                testOperation, nestedTestOperation1, nestedTestOperation2, nestedTestOperation3);
+
+            await Fixture.ReseedAsync();
+        }
+
         protected override bool SupportsDatabaseDefaults
             => false;