[BUG] ATOMIC_REQUESTS = True does not roll back transactions when exceptions are raised inside view functions

[javialon26]

Bug Report

Summary

When Django's ATOMIC_REQUESTS = True is enabled, transactions are not rolled back when an exception is raised inside a Django Ninja endpoint (or a service called by it), even with DEBUG=False. This includes both HttpError and standard Python exceptions like ValueError.

Environment

• django-ninja: 1.6.2
• Django: 5.2
• ATOMIC_REQUESTS: True

Expected Behavior

Per Django's documentation, ATOMIC_REQUESTS = True wraps every request in a transaction.atomic() block. Any exception that propagates out of the view should trigger a rollback of all database writes made during that request.

Actual Behavior

Database writes made before the exception are committed, not rolled back.

Root Cause

Operation.run() in ninja/operation.py wraps the entire view call in a try/except Exception block and routes all exceptions to self.api.on_exception().

This means no exception ever propagates out of Ninja's view layer to Django's transaction middleware.

For HttpError specifically, the registered handler in ninja/errors.py (_default_http_error) always returns an HttpResponse and never re-raises — regardless of the DEBUG setting. For generic exceptions, _default_exception re-raises only when DEBUG=False, but HttpError is matched first via MRO lookup and never reaches that branch.

Django's TransactionMiddleware receives a clean HttpResponse in all cases and interprets it as a successful request → COMMIT.
Relevant code path:

• ninja/operation.py — Operation.run(), the except Exception block
• ninja/errors.py — _default_http_error() (never re-raises)
• ninja/errors.py — _default_exception() (re-raises only for non-HttpError in DEBUG=False)

Minimal Reproduction

# models.py
class MyRecord(models.Model):
    name = models.CharField(max_length=100)
# api.py
@router.post("/test/")
def test_endpoint(request):
    MyRecord.objects.create(name="should be rolled back")
    raise HttpError(409, "conflict")  # record is NOT rolled back

With ATOMIC_REQUESTS = True, MyRecord is persisted in the database despite the HttpError(409) being raised.

Suggested Fix

Operation.run() should re-raise exceptions after calling on_exception() returns, OR Django Ninja could mark the transaction for rollback explicitly (via transaction.set_rollback(True)) before returning the error response.