Does ndb.toplevel break transactions?

Question

The following code works as expected and does not trigger the assertion:

@ndb.transactional
@ndb.tasklet
def Foo():
  assert ndb.in_transaction()


        

Answer 1

I discovered that the problems is that both create new contexts. transactional creates a context and ensures that all writes that happen inside of it are non-conflicting. toplevel creates a context and ensures that all futures that are created inside of it are resolved.

As a result, toplevel is clobbering transaction's context. The two just can't be combined in their current implementation.