Microsoft.Data.SQLite: Reader is not correctly closed when an exception occurs on DbCommand.ExecuteScalar() with 3.0.0-preview8

[T18970237136]

When using Microsoft.Data.SQLite version 3.0.0-preview8.19405.11, when executing a command with ExecuteNonQuery, ExecuteScalar or ExecuteReader causes an exception, we cannot change the CommandText on the DbCommand any more.

Steps to reproduce

• Create a new .NET Core 3.0 console project on Windows using .NET Core SDK 3.0.100 - preview8.
• Add <PackageReference Include="Microsoft.Data.SQLite" Version="3.0.0-preview8.19405.11" />
• Add the following code in Program.cs:

using System.Data.Common;
using Microsoft.Data.Sqlite;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var conSb = new SqliteConnectionStringBuilder();
            conSb.DataSource = ":memory:";

            using (var con = new SqliteConnection(conSb.ConnectionString)) {
                con.Open();

                using (var cmd = con.CreateCommand()) {
                    cmd.CommandText = "SELECT 1 FROM NonExistent;";
                    try {
                        cmd.ExecuteScalar();
                    }
                    catch (DbException) {
                    }

                    cmd.CommandText = "SELECT 1;"; // fails
                    cmd.ExecuteScalar();
                }
            }
        }
    }
}

Expected behavior: Runs without exception.
Actual behavior:
Exception message: System.InvalidOperationException: 'An open reader is associated with this command. Close it before changing the CommandText property.'
Stack trace:

   at Microsoft.Data.Sqlite.SqliteCommand.set_CommandText(String value)
   at Test.Program.Main(String[] args) in C:\Users\developer4\Desktop\DebugMicrosoftSqlite\Program.cs:line 24

This problem doesn't occur when using version 2.2.6 of Microsoft.Data.SQLite.

Workaround: Close the DbCommand and create a new one for executing the next command.

Further technical details

EF Core version: 3.0.0-preview8.19405.11
Database Provider: Microsoft.Data.SQLite
Operating system: Windows 10 Version 1903 x64
IDE: Visual Studio 2019 16.2.3

Thanks!

[bricelam]

This is a by-design side effect of fixing #13830. (which had a few other subtle breaking changes like this)

I think #14044 will enable us to go back to the previous, more flexible behavior.

[bricelam]

Oh wait, you called ExecuteScalar, so there shouldn't be an open data reader after the error. We should investigate.