On MySQL backend, with the admin app enabled, if the admin view is in an atomic block, TransactionManagementError is raised.

For this particular case we have installed:

• Django==1.10.6
• django-reversion==2.0.8
• django-import-export==0.5.1
• We use the django.contrib.admin app

In this particular project we are using these settings:

• ATOMIC_REQUESTS: True for all databases
• We have to add this middleware: reversion.middleware.RevisionMiddleware

When any admin view runs, these settings always run the view in an atomic block (in a transaction). Now, when importing a file with a Resource and an ImportExportModelAdmin in the admin app, we always get this error: TransactionManagementError: This is forbidden when an 'atomic' block is active..

This is because import_export.resource.Resource.import_data() tests for connection.features.supports_transaction. This is OK on most RDBMS, but on MySQL the support for transactions depends on the database engine being used, so Django runs a test to see if the DB supports transactions. During the test, a temporary table is created and also calls set_autocommit(False). That call can only be executed outside of an atomic block (Django code test for in_atomic_block for the DB connection).

This also has the side effect the table created by Django (called ROLLBACK_TEST) to test transaction support is never deleted from the DB, because the rollback to the savepoint marked by Django is never performed.

I’ll submit a Pull Request with a short patch to prevent this: if the import_data() is running inside an atomic block, then we know the DB supports transactions and we don’t test for connection.features.supports_transaction.

[bmihelac]

great news, thank you 😃

[bmihelac]

Hello @camilotorresf, @int-ua

thanks for your report. I have make some changes to transactions handling.

It would be great if you could check if problem persists when using refactor-transaction-handling branch that is available on https://github.com/bmihelac/django-import-export/tree/refactor-transaction-handling

If there are still problems it would be very useful to create test case or at least minimum application that can be shared on github and where issue can be easily reproduced.