TransactionScope does not work with async/await method on linux

Question

I was developing a blog project based on asp.net core mvc and trying to deploy my project on ubuntu 16.04 LTS x86-64.

And I encountered a null reference exception while using transactionScope with dapper on inserting object to sql server.

The SQL server version is: 12.0.4100.1 running on a Windows 2012SP1 system. and the code was running just fine on Windows 10 (OS Build 17074.1002). but when I deploy the project to Ubuntu, it throws null reference exceptions.

the exception details was like:

{System.NullReferenceException: Object reference not set to an instance of an object. at System.Data.ProviderBase.DbConnectionPool.DeactivateObject(DbConnectionInternal obj) at System.Data.ProviderBase.DbConnectionPool.PutObject(DbConnectionInternal obj, Object owningObject) at System.Data.ProviderBase.DbConnectionInternal.CloseConnection(DbConnection owningObject, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.CloseInnerConnection() at System.Data.SqlClient.SqlConnection.Close() at Dapper.SqlMapper.d__64 1.MoveNext() in C:\projects\dapper\Dapper\SqlMapper.Async.cs:line 1191 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
at System.Runtime.CompilerServices.TaskAwaiter 1.GetResult() at Autyan.NiChiJou.Repository.Dapper.BaseDapperRepository 1.d__22.MoveNext() in /home/alex/Documents/Github/Autyan.NiChiJou/src/Autyan.NiChiJou.Repository.Dapper/BaseDapperRepository.cs:line 167 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
at System.Runtime.CompilerServices.TaskAwaiter 1.GetResult() at Autyan.NiChiJou.Repository.Dapper.LongKeyDapperRepository 1.d__1.MoveNext() in /home/alex/Documents/Github/Autyan.NiChiJou/src/Autyan.NiChiJou.Repository.Dapper/LongKeyDapperRepository.cs:line 23 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
at System.Runtime.CompilerServices.TaskAwaiter 1.GetResult() at Autyan.NiChiJou.Service.Blog.ArticleService.d__10.MoveNext() in /home/alex/Documents/Github/Autyan.NiChiJou/src/Autyan.NiChiJou.Service.Blog/ArticleService.cs:line 39}

my code that throws exception is like this:

using (var scope = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
{
    var create = await ArticleRepo.InsertAsync(article);
    if (create <= 0)
    {
        return Failed<Article>("create article failed");
    }
    create = await ContentRepo.InsertAsync(new ArticleContent
    {
        ArticleId = create,
        Content = content
    });
    if (create <= 0)
    {
        return Failed<Article>("create articleContent failed");
    }
    scope.Complete();
}

I tried to remove the transactionScope and after that, my codes run just fine with everything

the new code was like:

var create = await ArticleRepo.InsertAsync(article);
if (create <= 0)
{
    return Failed<Article>("create article failed");
}
create = await ContentRepo.InsertAsync(new ArticleContent
{
    ArticleId = create,
    Content = content
});
if (create <= 0)
{
    return Failed<Article>("create articleContent failed");
}

Am I using trancsationScope the wrong way? Or it's just a bug from dotnet core itself?

rahulaga_dev rahulaga_dev · Accepted Answer · 2018-03-03T11:16:38

It is because when await is over, thread assigned to continue execution of statements following await already lost the transaction context that original executing thread had.

Define your Txn Scope as :

using (var scope = new TransactionScope(..., TransactionScopeAsyncFlowOption.Enabled))

TransactionScope does not work with async/await method on linux

1 Answers