Every time a new async task when want to create tickets over API, when creation is not finished

[gerhard1712]

Problem and impact

When call the "GET /api/v1/organizers/(organizer)/events/(event)/orders/(code)/download/pdf/"-function and the file does not yet exist, a RetryException will caused. And a new async task is created.
In Code src/pretix/api/views/order.py in the download function (line 346)

        ct = CachedCombinedTicket.objects.filter(
            order=order, provider=provider.identifier, file__isnull=False
        ).last()
        if not ct or not ct.file:
            generate.apply_async(args=('order', order.pk, provider.identifier))
            raise RetryException()

When i call every second this api call, a new async task will be created when the file not exist.
This result to 100% cpu usage for pretix worker, because multiple task exists for the same order_id
Is this a bug or intended behavior?

Expected behaviour

No response

Steps to reproduce

1, Take a order with many different products
2, Mark order as paid or set valid_if_pending to true
3, Call the "GET /api/v1/organizers/(organizer)/events/(event)/orders/(code)/download/pdf/"-function every second when 409 occour

Screenshots

No response

Link

No response

Browser (software, desktop or mobile?) and version

No response

Operating system, dependency versions

No response

Version

2023.10.0

[wiffbi]

Thanks for reporting, we will look into this.