From 05d1ddd616fc159d76e6ee52ae9b4994d6b3f340 Mon Sep 17 00:00:00 2001
From: Andriy Svyryd <Andriy.Svyryd@microsoft.com>
Date: Wed, 28 Oct 2020 16:36:54 -0700
Subject: [PATCH] Add quirk mode for #23092

---
 .../Metadata/Conventions/SqlServerIndexConvention.cs         | 5 ++++-
 .../Conventions/ForeignKeyPropertyDiscoveryConvention.cs     | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/EFCore.SqlServer/Metadata/Conventions/SqlServerIndexConvention.cs b/src/EFCore.SqlServer/Metadata/Conventions/SqlServerIndexConvention.cs
index d2098a6061f..4ae01369054 100644
--- a/src/EFCore.SqlServer/Metadata/Conventions/SqlServerIndexConvention.cs
+++ b/src/EFCore.SqlServer/Metadata/Conventions/SqlServerIndexConvention.cs
@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -201,12 +202,14 @@ private List<string> GetNullableColumns(IIndex index)
                 return null;
             }
 
+            var useOldBehavior = AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue23092_2", out var isEnabled) && isEnabled;
             var nullableColumns = new List<string>();
             var table = StoreObjectIdentifier.Table(tableName, index.DeclaringEntityType.GetSchema());
             foreach (var property in index.Properties)
             {
                 var columnName = property.GetColumnName(table);
-                if (columnName == null)
+                if (columnName == null
+                    && !useOldBehavior)
                 {
                     return null;
                 }
diff --git a/src/EFCore/Metadata/Conventions/ForeignKeyPropertyDiscoveryConvention.cs b/src/EFCore/Metadata/Conventions/ForeignKeyPropertyDiscoveryConvention.cs
index df708483000..d1287374a88 100644
--- a/src/EFCore/Metadata/Conventions/ForeignKeyPropertyDiscoveryConvention.cs
+++ b/src/EFCore/Metadata/Conventions/ForeignKeyPropertyDiscoveryConvention.cs
@@ -129,12 +129,15 @@ private IConventionForeignKeyBuilder DiscoverProperties(
             IConventionForeignKeyBuilder relationshipBuilder,
             IConventionContext context)
         {
+            var useOldBehavior = AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue23092_1", out var isEnabled) && isEnabled;
+
             var foreignKey = relationshipBuilder.Metadata;
             var foreignKeyProperties = FindCandidateForeignKeyProperties(relationshipBuilder.Metadata, onDependent: true);
             var propertiesConfigurationSource = foreignKey.GetPropertiesConfigurationSource();
             if (!ConfigurationSource.Convention.OverridesStrictly(propertiesConfigurationSource)
                 && (propertiesConfigurationSource != ConfigurationSource.Convention
-                    || (foreignKey.Properties.All(p => !p.IsImplicitlyCreated())
+                    || (!useOldBehavior
+                        && foreignKey.Properties.All(p => !p.IsImplicitlyCreated())
                         && (foreignKeyProperties == null
                             || !foreignKey.Properties.SequenceEqual(foreignKeyProperties)))))
             {