go-sqlcmd: Parsing error with database name

Hello,

Thank you for addressing the issue with the __ variable names yesterday. Our script generated from SQL Server Data Tools is now parsing further with go-sqlcmd, but not completely yet. There appears to be another gap (and one oddity that I need to think about before complaining about it).

The script contains a section similar to this fairly boiled-down repro:

GO
:setvar DatabaseName "MyTestDatabaseGitHub20230120"

GO

IF (DB_ID(N'$(DatabaseName)') IS NOT NULL)
BEGIN
    ALTER DATABASE [$(DatabaseName)]
    SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
    DROP DATABASE [$(DatabaseName)];
END
GO

CREATE DATABASE [$(DatabaseName)]

GO
USE [$(DatabaseName)]
GO

When I save the above script to a .sql file and run it with go-sqlcmd, using ./sqlcmd -b -i testdb.sql -U SA, this script returns the following error:

Msg 105, Level 15, State 1, Server c6c5144e6044, Line 2
Unclosed quotation mark after the character string ') IS NOT NULL)
BEGIN
    ALTER DATABASE [MyTestDatabaseGitHub20230120]
    SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
    DROP DATABASE [MyTestDatabaseGitHub20230120];
END'.

When run with legacy sqlcmd using the same options, the output looks like the below, which is the desired output, and the database is dropped and created. (note the very first time you run it, it won’t output the first four lines because it does not enter the if block):

2023-01-20 16:56:50.44 spid52      Setting database option SINGLE_USER to ON for database 'MyTestDatabaseGitHub20230120'.
2023-01-20 16:56:50.82 spid52      Starting up database 'MyTestDatabaseGitHub20230120'.
2023-01-20 16:56:50.87 spid52      Parallel redo is started for database 'MyTestDatabaseGitHub20230120' with worker pool size [1].
2023-01-20 16:56:50.90 spid52      Parallel redo is shutdown for database 'MyTestDatabaseGitHub20230120' with worker pool size [1].
Changed database context to 'MyTestDatabaseGitHub20230120'.

Please let me know if I can provide any additional information. I believe this is some sort of parsing/replacement bug but my Go skills are insufficient to create a failing unit test.