Best way to avoid RelatedObjectDoesNotExist on row_result.object_repr attribute initialisation

Hello, I have 2 models:

class Candidate(models.Model):
    first_name = models.CharField(_("First name"), max_length=255)

class Test(models.Model):
    candidate = models.OneToOneField(Candidate)

    def __str__(self):
        return self.candidate.first_name

In Test model candidate is required field and I want to show first_name in Django admin (in selects, for example)

When I try to import data for Test model, I get RelatedObjectDoesNotExist. This line of code https://github.com/django-import-export/django-import-export/blob/master/import_export/resources.py#L414 throw an Exception for newly created instances, before I can skip invalid rows.

Do you have any best practices to avoid this kind of error on import? I’m not sure that I really like an idea always check FK existence in __str__ method to fix this behaviour, but can’t think of something better. Thanks.

[browniebroke]

Regarding the importing of RelatedObjectDoesNotExist, it’s actually a property of Django’s ReverseSingleRelatedObjectDescriptor which, if you look at the code, raises actually the DoesNotExist of the related field, which has for base class ObjectDoesNotExist

class ReverseSingleRelatedObjectDescriptor(object):

    @cached_property
    def RelatedObjectDoesNotExist(self):
        return type(
            str('RelatedObjectDoesNotExist'),
            (self.field.rel.to.DoesNotExist, AttributeError),
            {}
        )

To complete @JarnoRFB comment above, I think the try-except should be limited to this exception in the __str__ (or __unicode__ in python 2) like below, and return something safe and recognisable in case of failure:

from django.conf import settings
from django.core.exceptions import ObjectDoesNotExist
from django.db import models

class MyModel(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)

    def __unicode__(self):
        try:
            return "{0}".format(self.user)
        except ObjectDoesNotExist:
            return "[MyModel instance]"

[jschneier]

This should be fixed in master now.