id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
31315	Closing all connections in function tagged with @transaction_atomic or transaction atomic block breaks atomicity	David Eling	nobody	"Bug might be related to https://code.djangoproject.com/ticket/21239

If you use the transaction atomic tag on a function ala 
{{{
@transaction.atomic
def post(self, request):
   Machine.objects.create(name=""a"")
   connections.close_all()
   connection.connect()
   list(Machine.objects.all())
   Machine.objects.create(name=""b"")
       
   return JsonResponse({})
}}}
b will exist but a will not. 

Now the code above is way simplified compared to what actually caused the bug in my codebase but it replicates the issue (although it seems very arbitrary in its current form) The codebase in question is very complex and involves multiple databases on different machines, this is my best attempt at boiling it down to what bits caused what. So it calls connections.close_all() and then reopens the connection to the current db then does a query then later down the line it does a create. 

The issue will occur if you do this instead 
{{{
def post(self, request):
   with transaction.atomic():
      Machine.objects.create(name=""a"")
      connections.close_all()
      connection.connect()
      list(Machine.objects.all())
      Machine.objects.create(name=""b"")
       
    return JsonResponse({})
}}}

During further testing it looks like swapping connections.close_all() with connection.close() still causes the issue to occur, so maybe the fix in the issue linked above did not fix the issue all the way. 

It's possible this bug is only happening due to the code exploiting some loophole or something but I just thought I would put this here just in case it might be a real problem that needs to be fixed. Within our code base we had to isolate the offending bit and do it before entering the atomic block. 

This is my first time reporting a django bug so I apologize for any issues. "	Bug	closed	Database layer (models, ORM)	2.1	Normal	wontfix			Unreviewed	0	0	0	0	0	0