Error - module 'django.db.models' has no attribute 'FieldDoesNotExist' when adding FK relationship object

[Lloyd Dube]

Hi,

I have two models, ReleaseImageGallery and ReleaseImage as follows:

class ReleaseImageGallery(BaseImageGallery):

release = models.ForeignKey(Release, on_delete=models.CASCADE)

class Meta:

verbose_name = "release image gallery"

verbose_name_plural = "release image galleries"

and

class ReleaseImage(BaseImage):

release_image_gallery = models.ForeignKey(ReleaseImageGallery,

on_delete=models.CASCADE)

image = models.ImageField(upload_to='release-images/', blank=True, null=True)

class Meta:

verbose_name = "release image"

verbose_name_plural = "release images"

My admin.py file is as follows:

from django.contrib import admin

from .models import ReleaseImageGallery, ReleaseImage

class ReleaseImageInline(admin.StackedInline):

model = ReleaseImage

extra = 1

class ReleaseImageGalleryAdmin(admin.ModelAdmin):

inlines = [ReleaseImageInline]

list_filter = ['date_created', 'date_modified']

search_fields = ['title']

admin.site.register(ReleaseImageGallery, ReleaseImageGalleryAdmin)

When I run the project and log into the admin site, all works fine.

While creating a new ReleaseImageGallery, I try to add a new Release object (FK relationship) via a select list, an error is raised in the add_view as follows:



```
Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/admin/releases/release/add/?_to_field=id&_popup=1

Django Version: 3.2.5
Python Version: 3.9.6
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'tinymce',
 'nested_inline',
 'coresite.apps.CoreSiteConfig',
 'customadminoptions.apps.CustomAdminOptionsConfig',
 'baseimagegalleries.apps.BaseImageGalleriesConfig',
 'baseusers.apps.UsersConfig',
 'userprofiles.apps.UserProfilesConfig',
 'artists.apps.ArtistsConfig',
 'artistimagegalleries.apps.ArtistImageGalleriesConfig',
 'bands.apps.BandsConfig',
 'labels.apps.LabelsConfig',
 'releaseimagegalleries.apps.ReleaseImageGalleriesConfig',
 'releases.apps.ReleasesConfig']
Installed Middleware:
('whitenoise.middleware.WhiteNoiseMiddleware',
 'django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware')



Traceback (most recent call last):
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/db/models/options.py", line 608, in get_field
    return self.fields_map[field_name]

During handling of the above exception ('_to_field'), another exception occurred:
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/nested_inline/admin.py", line 217, in add_view
    f = opts.get_field(k)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/db/models/options.py", line 610, in get_field
    raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, field_name))

During handling of the above exception (Release has no field named '_to_field'), another exception occurred:
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/contrib/admin/options.py", line 616, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/contrib/admin/sites.py", line 232, in inner
    return view(request, *args, **kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/utils/decorators.py", line 43, in _wrapper
    return bound_method(*args, **kwargs)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/usr/local/Cellar/python@3.9/3.9.6/Frameworks/Python.framework/Versions/3.9/lib/python3.9/contextlib.py", line 79, in inner
    return func(*args, **kwds)
  File "/Users/sd/Library/Caches/pypoetry/virtualenvs/afridisc-sWjK8x-o-py3.9/lib/python3.9/site-packages/nested_inline/admin.py", line 218, in add_view
    except models.FieldDoesNotExist:

Exception Type: AttributeError at /admin/releases/release/add/
Exception Value: module 'django.db.models' has no attribute 'FieldDoesNotExist'

```

I have checked the class definitions and do not understand the breakage. What am I missing?

TIA.

Regards,
~ Lloyd

[Lloyd Dube]

Addendum: the Release model is declared as follows:

from django.db import models

from tinymce import models as tinymce_models

from artists.models import Artist

from bands.models import Band

from labels.models import Label

class Release(models.Model):

artist = models.ForeignKey(Artist, on_delete=models.CASCADE)

band = models.ForeignKey(

Band,

on_delete=models.CASCADE,

blank=True, null=True

)

title = models.CharField(max_length=200)

label = models.ForeignKey(Label, on_delete=models.CASCADE)

cat_no = models.CharField(

max_length=200,

blank=True,

null=True,

default='UNKNOWN'

)

country = models.CharField(

max_length=200,

blank=True,

null=True,

default=None

)

RELEASE_FORMAT_CHOICES = [

('LP', 'LP'),

('10INCHALBUM', '10" ALBUM'),

('7INCHEP', '7" EP'),

('12INCHEP', '12" EP'),

('12INCHSINGLE', '12" SINGLE'),

('10INCHSINGLE', '10" SINGLE'),

('7INCHSINGLE', '7" SINGLE'),

]

release_format = models.CharField(

max_length=200,

choices=RELEASE_FORMAT_CHOICES,

blank=True,

null=True,

default=None

)

year = models.PositiveSmallIntegerField()

genre = models.CharField(

max_length=200,

blank=True,

null=True,

default=None

)

bio = tinymce_models.HTMLField(blank=True, null=True)

date_created = models.DateTimeField(auto_now_add=True)

date_modified = models.DateTimeField(auto_now=True)

class Meta:

verbose_name = "release"

verbose_name_plural = "releases"

def __str__(self):

return self.title

I suspect that something is going on with migrations. All migrations have been run and a user is already capturing data on a staging server, so I do not want to recreate the database.

Regards,
~ Lloyd

[David Crandell]

Try adding related_name='+' to your FK definition.

class ReleaseImageGallery(BaseImageGallery):

release = models.ForeignKey(Release, related_name='+', on_delete=models.CASCADE)

class Meta:

verbose_name = "release image gallery"

verbose_name_plural = "release image galleries"