From c5c9b0ed48a59d1fec6140e93644b7cb08e6bb27 Mon Sep 17 00:00:00 2001
From: Arthur Vickers <ajcvickers@hotmail.com>
Date: Wed, 27 Jun 2018 17:50:56 -0700
Subject: [PATCH] [2.1.3] Add quirks for in-memory concurrency patch fix

Issue #12214
---
 .../Storage/Internal/InMemoryTable.cs         | 20 +++--
 .../UpdatesInMemoryTestBase.cs                | 77 +++++++++++++++++++
 2 files changed, 91 insertions(+), 6 deletions(-)

diff --git a/src/EFCore.InMemory/Storage/Internal/InMemoryTable.cs b/src/EFCore.InMemory/Storage/Internal/InMemoryTable.cs
index fc2a2f8f0a6..17a1847020b 100644
--- a/src/EFCore.InMemory/Storage/Internal/InMemoryTable.cs
+++ b/src/EFCore.InMemory/Storage/Internal/InMemoryTable.cs
@@ -89,14 +89,22 @@ private static bool IsConcurrencyConflict(
             object rowValue,
             Dictionary<IProperty, object> concurrencyConflicts)
         {
-            if (property.IsConcurrencyToken
-                && !StructuralComparisons.StructuralEqualityComparer.Equals(
-                    rowValue,
-                    entry.GetOriginalValue(property)))
+            if (property.IsConcurrencyToken)
             {
-                concurrencyConflicts.Add(property, rowValue);
+                var originalValue = entry.GetOriginalValue(property);
 
-                return true;
+                var revertPatchBehavior = AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue12214", out var isEnabled)
+                                          && isEnabled;
+
+                if ((revertPatchBehavior
+                    && !Equals(rowValue, originalValue))
+                    || (!revertPatchBehavior
+                        && !StructuralComparisons.StructuralEqualityComparer.Equals(rowValue, originalValue)))
+                {
+                    concurrencyConflicts.Add(property, rowValue);
+
+                    return true;
+                }
             }
 
             return false;
diff --git a/test/EFCore.InMemory.FunctionalTests/UpdatesInMemoryTestBase.cs b/test/EFCore.InMemory.FunctionalTests/UpdatesInMemoryTestBase.cs
index 95f1663dd23..cfcf5e5cefd 100644
--- a/test/EFCore.InMemory.FunctionalTests/UpdatesInMemoryTestBase.cs
+++ b/test/EFCore.InMemory.FunctionalTests/UpdatesInMemoryTestBase.cs
@@ -9,6 +9,7 @@
 using Microsoft.EntityFrameworkCore.InMemory.Internal;
 #endif
 using Microsoft.EntityFrameworkCore.TestModels.UpdatesModel;
+using Xunit;
 
 namespace Microsoft.EntityFrameworkCore
 {
@@ -20,6 +21,82 @@ protected UpdatesInMemoryTestBase(TFixture fixture)
         {
         }
 
+#if !Test20
+        [Fact]
+        public virtual void Update_on_bytes_concurrency_token_original_value_matches_throws_with_quirk()
+        {
+            var productId = new Guid("984ade3c-2f7b-4651-a351-642e92ab7146");
+
+            try
+            {
+                AppContext.SetSwitch("Microsoft.EntityFrameworkCore.Issue12214", true);
+
+                ExecuteWithStrategyInTransaction(
+                    context =>
+                    {
+                        var entry = context.ProductWithBytes.Attach(
+                            new ProductWithBytes
+                            {
+                                Id = productId,
+                                Name = "MegaChips",
+                                Bytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 }
+                            });
+
+                        entry.Entity.Name = "GigaChips";
+
+                        Assert.Throws<DbUpdateConcurrencyException>(
+                            () => context.SaveChanges());
+                    },
+                    context =>
+                    {
+                        Assert.Equal("MegaChips", context.ProductWithBytes.Find(productId).Name);
+                    });
+
+            }
+            finally
+            {
+                AppContext.SetSwitch("Microsoft.EntityFrameworkCore.Issue12214", false);
+            }
+        }
+
+        [Fact]
+        public virtual void Remove_on_bytes_concurrency_token_original_value_matches_throws_with_quirk()
+        {
+            var productId = new Guid("984ade3c-2f7b-4651-a351-642e92ab7146");
+
+            try
+            {
+                AppContext.SetSwitch("Microsoft.EntityFrameworkCore.Issue12214", true);
+
+                ExecuteWithStrategyInTransaction(
+                    context =>
+                    {
+                        var entry = context.ProductWithBytes.Attach(
+                            new ProductWithBytes
+                            {
+                                Id = productId,
+                                Name = "MegaChips",
+                                Bytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 }
+                            });
+
+                        entry.State = EntityState.Deleted;
+
+                        Assert.Throws<DbUpdateConcurrencyException>(
+                            () => context.SaveChanges());
+                    },
+                    context =>
+                    {
+                        Assert.Equal("MegaChips", context.ProductWithBytes.Find(productId).Name);
+                    });
+
+            }
+            finally
+            {
+                AppContext.SetSwitch("Microsoft.EntityFrameworkCore.Issue12214", false);
+            }
+        }
+#endif
+
         protected override string UpdateConcurrencyMessage
             => InMemoryStrings.UpdateConcurrencyException;