restore SqlAuthenticationMethod workaround removed prematurely

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;CS0649;CS8632;NU1608;NU1109</NoWarn>
-    <Version>12.1.1</Version>
+    <Version>12.1.2</Version>
     <LangVersion>preview</LangVersion>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>SqlServer, Verify</PackageTags>

src/Tests/Tests.cs

@@ -852,10 +852,11 @@ await Verify(connection)
             .SchemaFilter(_ => _.Name is "MyTable" or "MyView" or "MyProcedure");
     }
 
-    // Verifies the workaround for SMO 181.15.0 + SqlClient 7.0 TypeLoadException.
-    // SMO's ServerConnection(SqlConnection) constructor references SqlAuthenticationMethod
-    // which moved from Microsoft.Data.SqlClient to Extensions.Abstractions in SqlClient 7.0.
-    // The fix avoids that constructor by using reflection to set the SqlConnection directly.
+    // Exercises Verify(SqlConnection) with an already-open connection.
+    // Note: this test uses LocalDb (Windows auth) so it passes even if the
+    // SqlAuthenticationMethod workaround is removed — Windows auth does not
+    // trigger the SMO type-load for SqlAuthenticationMethod.
+    // See SqlConnectionObjectFieldWorkaround for the regression guard.
     [Test]
     public async Task SchemaFromOpenConnection()
     {
@@ -866,4 +867,26 @@ await Verify(connection)
             .SchemaFilter(_ => _.Name == "MyTable")
             .SchemaIncludes(DbObjects.Tables);
     }
+
+    // Regression: commit fbfa399 removed SqlConnectionObjectField from SqlScriptBuilder,
+    // which broke Verify(SqlConnection) for connections using SQL Server authentication.
+    // When SMO 181.x + SqlClient 7.x opens a new connection from a SQL-auth connection
+    // string it tries to load SqlAuthenticationMethod — a type moved in SqlClient 7.0 —
+    // causing a TypeLoadException surfaced as "Login failed for user 'sa'".
+    // The fix injects the already-open SqlConnection directly into SMO via reflection,
+    // so SMO reuses it and never runs the SQL-auth type-load code path.
+    [Test]
+    public void SqlConnectionObjectFieldWorkaround()
+    {
+        var field = SqlScriptBuilder.SqlConnectionObjectField;
+        Assert.That(field, Is.Not.Null,
+            "SqlConnectionObjectField must exist to work around SMO+SqlClient 7.x TypeLoadException for SQL Server auth connections");
+        Assert.That(field.Name, Is.EqualTo("m_SqlConnectionObject"));
+
+        // Verify the field can actually be set on a ServerConnection instance
+        var serverConnection = new ServerConnection { NonPooledConnection = true };
+        using var sqlConnection = new SqlConnection("Server=.;Database=test;Integrated Security=True");
+        field.SetValue(serverConnection, sqlConnection);
+        Assert.That(field.GetValue(serverConnection), Is.SameAs(sqlConnection));
+    }
 }

src/Verify.SqlServer/GlobalUsings.cs

@@ -1,4 +1,5 @@
 global using System.Data;
+global using System.Reflection;
 global using System.Data.Common;
 global using System.Data.SqlTypes;
 global using System.Globalization;

src/Verify.SqlServer/SchemaValidation/SqlScriptBuilder.cs

@@ -1,5 +1,20 @@
 class SqlScriptBuilder(SchemaSettings settings)
 {
+    // TODO: when Microsoft.Data.SqlClient adds TypeForwardedTo for SqlAuthenticationMethod,
+    // revert to using new ServerConnection(SqlConnection) and remove this reflection workaround.
+    //
+    // SMO 181.15.0 ServerConnection(SqlConnection) constructor calls InitFromSqlConnection
+    // which references SqlAuthenticationMethod — a type moved from Microsoft.Data.SqlClient
+    // to Microsoft.Data.SqlClient.Extensions.Abstractions in SqlClient 7.0. The CLR can't
+    // resolve the type in the original assembly, causing a TypeLoadException.
+    //
+    // Workaround: construct ServerConnection() with default constructor (no InitFromSqlConnection),
+    // then set the internal m_SqlConnectionObject field via reflection to reuse the open connection.
+    // SMO detects the connection is already open and uses it directly.
+    internal static readonly FieldInfo SqlConnectionObjectField =
+        typeof(ConnectionManager).GetField("m_SqlConnectionObject", BindingFlags.NonPublic | BindingFlags.Instance) ??
+        throw new("Could not find field m_SqlConnectionObject on ConnectionManager. The SMO internals may have changed.");
+
     static Dictionary<string, string> tableSettingsToScrubLookup;
 
     static SqlScriptBuilder()
@@ -35,6 +50,7 @@ public string BuildContent(SqlConnection connection)
         };
         try
         {
+            SqlConnectionObjectField.SetValue(serverConnection, connection);
             var server = new Server(serverConnection);
             return BuildContent(server, builder);
         }