ForeignKey field with blank=True and null=True in list_display breaks admin

[Deniz Dogan]

When you have a model with a ForeignKey to another model with blank=True and null=True and use the foreign key in list_editable and the value is indeed "null" (i.e. no relation exists), the admin interface breaks with the following message:

Caught an exception while rendering: invalid literal for int() with base 10: ''

This is the code to reproduce it:

# models.py

from django.db import models

class Brand(models.Model):
    name = models.CharField(max_length=32, blank=True)

class Bicycle(models.Model):
    brand = models.ForeignKey(Brand, blank=True, null=True)
    kind = models.CharField(max_length=32)


#admin.py

from django.contrib import admin
from eplister.hello.models import *

class BrandAdmin(admin.ModelAdmin):
    model = Brand

class BicycleAdmin(admin.ModelAdmin):
    model = Bicycle
    list_display = ('kind', 'brand', )
    list_display_links = ('kind', )
    list_editable = ('brand', )

admin.site.register(Brand, BrandAdmin)
admin.site.register(Bicycle, BicycleAdmin)

[Deniz Dogan]

I just noticed that the following even smaller admin declaration breaks the admin with the same error message. Change the BicycleAdmin to the following:

class BicycleAdmin(admin.ModelAdmin):
    model = Bicycle
    list_display = ('kind', 'brand', )

[Daniel Gonzalez Gasull]

I can't reproduce this error and I tried in sqlite and in PostgreSQL. It just works as expected. To reopen the bug please give information about the DBMS used.

[Karen Tracey]

Possibly contributing to the recreation difficulty is that there is no description of what to do in the admin interface to trigger the error. It may seem obvious, but making it explicit (for example: Bring up the change list page for Bicycles after adding a Bicycle with no specified Brand) really helps. Also, the full traceback of the error would be helpful, not just the error message.

[Jacob]

Milestone 1.2 deleted