#30564: Cannot create custom field that returns a queryset AND uses pre_save(). -------------------------------------+------------------------------------- Reporter: Dan J Strohl | Owner: nobody Type: Bug | Status: closed Component: Database layer | Version: master (models, ORM) | Severity: Normal | Resolution: invalid Keywords: | Triage Stage: | Unreviewed Has patch: 0 | Needs documentation: 0 Needs tests: 0 | Patch needs improvement: 0 Easy pickings: 0 | UI/UX: 0 -------------------------------------+------------------------------------- Changes (by felixxm):
* status: new => closed * resolution: => invalid Comment: > Either way though, the bug I am reporting is that when returning a django queryset, via a custom field with a pre_save, it raises an AttributeError. Since these are all normal Django objects, and I'm using documented django approaches, I see this as a bug. Your custom field implementation is quite complicated. Custom fields with `pre_save()` works properly because you can treat any Django's field as a custom field e.g. `DateField`. It seems (but it is hard to tell without `pre_save_func()`) that in your case `pre_save()` returns `Query` which is not expected by `SQLInsertCompiler.prepare_value()`, that's why IMO it is an issue in your implementation/approach. > Since these are all normal Django objects. You cannot assume that Django internals will handle everything, even if these objects are defined by Django. I think that `return self.get_db_prep_value(value)` in `pre_save()` in branch with `pre_save_func()` should fix your issue. -- Ticket URL: <https://code.djangoproject.com/ticket/30564#comment:5> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-updates+unsubscr...@googlegroups.com. To post to this group, send email to django-updates@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/065.70da6bf7f642a2f576a11e5a07c225f0%40djangoproject.com. For more options, visit https://groups.google.com/d/optout.