From 6d4a1b374324be5fe6c7c9c576a05ac038979daa Mon Sep 17 00:00:00 2001
From: Arthur Vickers <ajcvickers@hotmail.com>
Date: Fri, 30 Jun 2017 15:15:21 -0700
Subject: [PATCH] Stop returning detached entries from the ChangeTracker

Issue #8921
---
 .../ChangeTracking/Internal/StateManager.cs   |  3 ++-
 .../ChangeTracking/EntityEntryTest.cs         | 24 +++++++++++++++++++
 .../Internal/StateManagerTest.cs              | 19 +++++++++++----
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/EFCore/ChangeTracking/Internal/StateManager.cs b/src/EFCore/ChangeTracking/Internal/StateManager.cs
index 6b790562a4e..4bc1c8b1294 100644
--- a/src/EFCore/ChangeTracking/Internal/StateManager.cs
+++ b/src/EFCore/ChangeTracking/Internal/StateManager.cs
@@ -377,7 +377,8 @@ private IIdentityMap FindIdentityMap(IKey key)
         ///     directly from your code. This API may change or be removed in future releases.
         /// </summary>
         public virtual IEnumerable<InternalEntityEntry> Entries => _entityReferenceMap.Values
-            .Concat(_dietReferenceMap.Values.SelectMany(e => e.Values));
+            .Concat(_dietReferenceMap.Values.SelectMany(e => e.Values))
+            .Where(e => e.EntityState != EntityState.Detached);
 
         /// <summary>
         ///     This API supports the Entity Framework Core infrastructure and is not intended to be used
diff --git a/test/EFCore.Tests/ChangeTracking/EntityEntryTest.cs b/test/EFCore.Tests/ChangeTracking/EntityEntryTest.cs
index ede7f2b6439..d9e772b5b08 100644
--- a/test/EFCore.Tests/ChangeTracking/EntityEntryTest.cs
+++ b/test/EFCore.Tests/ChangeTracking/EntityEntryTest.cs
@@ -128,6 +128,30 @@ protected internal override void OnModelCreating(ModelBuilder modelBuilder)
             }
         }
 
+        [Fact]
+        public void Detached_entities_are_not_returned_from_the_change_tracker()
+        {
+            using (var context = new FreezerContext())
+            {
+                var entity = new Chunky { Id = 808 };
+                context.Attach(entity);
+
+                Assert.Equal(1, context.ChangeTracker.Entries().Count());
+
+                context.Entry(entity).State = EntityState.Detached;
+
+                Assert.Equal(0, context.ChangeTracker.Entries().Count());
+
+                context.ChangeTracker.DetectChanges();
+
+                Assert.Equal(0, context.ChangeTracker.Entries().Count());
+
+                context.Entry(entity);
+
+                Assert.Equal(0, context.ChangeTracker.Entries().Count());
+            }
+        }
+
         [Fact]
         public void Can_obtain_entity_instance()
         {
diff --git a/test/EFCore.Tests/ChangeTracking/Internal/StateManagerTest.cs b/test/EFCore.Tests/ChangeTracking/Internal/StateManagerTest.cs
index c912e7268af..2e2a3c343c2 100644
--- a/test/EFCore.Tests/ChangeTracking/Internal/StateManagerTest.cs
+++ b/test/EFCore.Tests/ChangeTracking/Internal/StateManagerTest.cs
@@ -563,10 +563,21 @@ public void Can_get_all_entities()
             var productId1 = new Guid("984ade3c-2f7b-4651-a351-642e92ab7146");
             var productId2 = new Guid("0edc9136-7eed-463b-9b97-bdb9648ab877");
 
-            stateManager.StartTracking(stateManager.GetOrCreateEntry(new Category { Id = 77, PrincipalId = 777 }));
-            stateManager.StartTracking(stateManager.GetOrCreateEntry(new Category { Id = 78, PrincipalId = 778 }));
-            stateManager.StartTracking(stateManager.GetOrCreateEntry(new Product { Id = productId1 }));
-            stateManager.StartTracking(stateManager.GetOrCreateEntry(new Product { Id = productId2 }));
+            stateManager.StartTracking(
+                    stateManager.GetOrCreateEntry(new Category { Id = 77, PrincipalId = 777 }))
+                .SetEntityState(EntityState.Unchanged);
+
+            stateManager.StartTracking(
+                    stateManager.GetOrCreateEntry(new Category { Id = 78, PrincipalId = 778 }))
+                .SetEntityState(EntityState.Unchanged);
+
+            stateManager.StartTracking(
+                    stateManager.GetOrCreateEntry(new Product { Id = productId1 }))
+                .SetEntityState(EntityState.Unchanged);
+
+            stateManager.StartTracking(
+                    stateManager.GetOrCreateEntry(new Product { Id = productId2 }))
+                .SetEntityState(EntityState.Unchanged);
 
             Assert.Equal(4, stateManager.Entries.Count());