From e234d86f927667ee8603b8cbba43cfd3669a2bb3 Mon Sep 17 00:00:00 2001
From: Shay Rojansky <roji@roji.org>
Date: Mon, 1 Mar 2021 20:06:42 +0100
Subject: [PATCH] Quirk for #24272

---
 .../Migrations/SqlServerMigrationsSqlGenerator.cs        | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/EFCore.SqlServer/Migrations/SqlServerMigrationsSqlGenerator.cs b/src/EFCore.SqlServer/Migrations/SqlServerMigrationsSqlGenerator.cs
index 06f084f7d3c..0d1299d90a3 100644
--- a/src/EFCore.SqlServer/Migrations/SqlServerMigrationsSqlGenerator.cs
+++ b/src/EFCore.SqlServer/Migrations/SqlServerMigrationsSqlGenerator.cs
@@ -38,6 +38,9 @@ public class SqlServerMigrationsSqlGenerator : MigrationsSqlGenerator
         private IReadOnlyList<MigrationOperation> _operations;
         private int _variableCounter;
 
+        private static readonly bool _useOldAlterColumnDefaultValueLogic =
+            AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue24272", out var enabled) && enabled;
+
         /// <summary>
         ///     Creates a new <see cref="SqlServerMigrationsSqlGenerator" /> instance.
         /// </summary>
@@ -391,7 +394,11 @@ protected override void Generate(AddCheckConstraintOperation operation, IModel m
                 builder.AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);
             }
 
-            if (!Equals(operation.DefaultValue, oldDefaultValue) || operation.DefaultValueSql != oldDefaultValueSql)
+            var addDefaultValue = _useOldAlterColumnDefaultValueLogic
+                ? operation.DefaultValue != null || operation.DefaultValueSql != null
+                : !Equals(operation.DefaultValue, oldDefaultValue) || operation.DefaultValueSql != oldDefaultValueSql;
+
+            if (addDefaultValue)
             {
                 builder
                     .Append("ALTER TABLE ")