Occasional NullReferenceException when disposing

[llehn]

I sometimes - not always, get a NullRef when disposing:

System.NullReferenceException : Object reference not set to an instance of an object.
at Microsoft.Data.Sqlite.SqliteConnectionExtensions.ExecuteNonQuery(SqliteConnection connection, String commandText)
at Microsoft.Data.Sqlite.SqliteTransaction.RollbackInternal()
at Microsoft.Data.Sqlite.SqliteTransaction.Dispose(Boolean disposing)
at System.Data.Common.DbTransaction.Dispose()
at Microsoft.Data.Sqlite.SqliteConnection.Close()
at Microsoft.Data.Sqlite.SqliteConnection.Dispose(Boolean disposing)
at System.ComponentModel.Component.Dispose()

using version 2.0

[bricelam]

There's no obvious way of getting this exception from this code path. You may be calling Dispose() on two different threads. If you can provide us a simple repro, we can investigate further.

[StefanoD]

I've got this, too, on my system test. It ran well for many times and then I got NullReferenceException on closing the connection.

public class QlcContext : DbContext
{
	// ..

	private SqliteConnection connection;

	public override void Dispose()
	{
		base.Dispose();
		connection.Close(); // NullReferenceException 
	}

	protected override void OnConfiguring(DbContextOptionsBuilder contextOptionsBuilder)
	{
		connection = new SqliteConnection("Data Source=qlc.db");
		connection.Open();

		string password = "MyPass";

		var command = connection.CreateCommand();
		command.CommandText = "SELECT quote($password);";
		command.Parameters.AddWithValue("$password", password);
		var quotedPassword = (string)command.ExecuteScalar();

		command.CommandText = "PRAGMA key = " + quotedPassword;
		command.Parameters.Clear();
		command.ExecuteNonQuery();

		contextOptionsBuilder.UseSqlite(connection);
	}
}

My used packages:

<PackageReference Include="Microsoft.Data.Sqlite.Core" Version="2.0.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.0.1" />
<PackageReference Include="SQLitePCLRaw.bundle_sqlcipher" Version="1.1.9" />
<PackageReference Include="SQLitePCLRaw.bundle_green" Version="1.1.9" ExcludeAssets="All" />

[bricelam]

@StefanoD I wasn't able to get a NullRef, but I could repro #480. Try using version 1.1.7 of the SQlitePCL.raw packages.