#28972: `RelatedObjectDoesNotExist` during `loaddata` of models with multi-table
inheritance
-------------------------------------+-------------------------------------
Reporter: Kal Sze | Owner: nobody
Type: Bug | Status: new
Component: Core | Version: 2.0
(Serialization) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Kal Sze:
Old description:
> Software versions
> * Python 3.6.3
> * Django 2.0
> * django-model-utils 3.1.1 (from git)
> * PostgreSQL 9.4
> * psycopg2 2.7.3.2
>
> I have a `licenses` app, with these models:
> * `BaseLicense`, a concrete model, with a `ForeignKey` to
> `settings.AUTH_USER_MODEL`.
> * `CorelDrawLicense`, which inherits from `BaseLicense` through multi-
> table inheritance
> * `AdobePhotoshopLicense`, which inherits from `BaseLicense` through
> multi-table inheritance
>
> I created an instance of `AdobePhotoshopLicense`, then tried to do
> `manage.py dumpdata` and `manage.py loaddata`.
>
> `dumpdata` "worked" - there was no error.
>
> However, `loaddata` failed with this traceback:
> {{{
> Traceback (most recent call last):
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/serializers/json.py", line 69, in Deserializer
> yield from PythonDeserializer(objects, **options)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/serializers/python.py", line 170, in Deserializer
> obj = base.build_instance(Model, data, using)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/serializers/base.py", line 225, in build_instance
> natural_key = obj.natural_key()
> File "/home/kal/git/nk_test/licenses/models.py", line 33, in
> natural_key
> return (self.user.natural_key(), self.license_key)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/db/models/fields/related_descriptors.py", line 175, in
> __get__
> "%s has no %s." % (self.field.model.__name__, self.field.name)
> django.db.models.fields.related_descriptors.RelatedObjectDoesNotExist:
> BaseLicense has no user.
>
> The above exception was the direct cause of the following exception:
>
> Traceback (most recent call last):
> File "./manage.py", line 15, in <module>
> execute_from_command_line(sys.argv)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/__init__.py", line 371, in
> execute_from_command_line
> utility.execute()
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/__init__.py", line 365, in execute
> self.fetch_command(subcommand).run_from_argv(self.argv)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/base.py", line 288, in run_from_argv
> self.execute(*args, **cmd_options)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/base.py", line 335, in execute
> output = self.handle(*args, **options)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/commands/loaddata.py", line 72, in handle
> self.loaddata(fixture_labels)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/commands/loaddata.py", line 113, in
> loaddata
> self.load_label(fixture_label)
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/management/commands/loaddata.py", line 168, in
> load_label
> for obj in objects:
> File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
> packages/django/core/serializers/json.py", line 73, in Deserializer
> raise DeserializationError() from exc
> django.core.serializers.base.DeserializationError: Problem installing
> fixture '/home/kal/git/nk_test/./fixtures/dumpdata.json':
> }}}
>
> Here are the exact steps:
> 1. Create model instances in management shell
> {{{
> >>> from django.contrib.auth import get_user_model
> >>> User = get_user_model()
> >>> kal = User.objects.create_user('kal', '[email protected]', 'qwer1234')
> >>> from licenses.models import AdobePhotoshopLicense
> >>> l = AdobePhotoshopLicense.objects.create(user=kal,
> license_key='12345')
> }}}
>
> 2. Dump the data into a fixtures json
> {{{
> $ python manage.py dumpdata -o fixtures.json --format json --natural-
> foreign --natural-primary auth licenses
> }}}
>
> 3. Edit settings.py to switch to an empty database
> {{{
> DATABASES = {
> 'default': {
> 'ENGINE': 'django.db.backends.postgresql',
> #'NAME': 'nk_test',
> 'NAME': 'nk_test_2',
> 'USER': 'kal',
> 'HOST': '',
> 'PORT': 5432,
> }
> }
> }}}
>
> 4. Run migrations on the new empty database
> {{{
> $ python manage.py migrate
> }}}
>
> 5. Try to load the data from fixtures.json
> {{{
> $ python manage.py loaddata --format json fixtures.json
> }}}
>
> I have attached the models.py and fixtures.json file to the ticket.
>
> Also note that this bug doesn't have to do with my use of the custom
> `InheritanceManager`. I could let the `BaseLicense` model use the default
> manager and still get the same bug.
New description:
Software versions
* Python 3.6.3
* Django 2.0
* django-model-utils 3.1.1 (from git)
* PostgreSQL 9.4
* psycopg2 2.7.3.2
I have a `licenses` app, with these models:
* `BaseLicense`, a concrete model, with a `ForeignKey` to
`settings.AUTH_USER_MODEL`.
* `CorelDrawLicense`, which inherits from `BaseLicense` through multi-
table inheritance
* `AdobePhotoshopLicense`, which inherits from `BaseLicense` through
multi-table inheritance
I created an instance of `AdobePhotoshopLicense`, then tried to do
`manage.py dumpdata` and `manage.py loaddata`.
`dumpdata` "worked" - there was no error.
However, `loaddata` failed with this traceback:
{{{
Traceback (most recent call last):
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/serializers/json.py", line 69, in Deserializer
yield from PythonDeserializer(objects, **options)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/serializers/python.py", line 170, in Deserializer
obj = base.build_instance(Model, data, using)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/serializers/base.py", line 225, in build_instance
natural_key = obj.natural_key()
File "/home/kal/git/nk_test/licenses/models.py", line 33, in natural_key
return (self.user.natural_key(), self.license_key)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/db/models/fields/related_descriptors.py", line 175, in
__get__
"%s has no %s." % (self.field.model.__name__, self.field.name)
django.db.models.fields.related_descriptors.RelatedObjectDoesNotExist:
BaseLicense has no user.
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "./manage.py", line 15, in <module>
execute_from_command_line(sys.argv)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/__init__.py", line 371, in
execute_from_command_line
utility.execute()
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/__init__.py", line 365, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/base.py", line 335, in execute
output = self.handle(*args, **options)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/commands/loaddata.py", line 72, in handle
self.loaddata(fixture_labels)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/commands/loaddata.py", line 113, in
loaddata
self.load_label(fixture_label)
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/management/commands/loaddata.py", line 168, in
load_label
for obj in objects:
File "/home/kal/.virtualenvs/nk_test-5iWsqJVv/lib/python3.6/site-
packages/django/core/serializers/json.py", line 73, in Deserializer
raise DeserializationError() from exc
django.core.serializers.base.DeserializationError: Problem installing
fixture '/home/kal/git/nk_test/./fixtures/dumpdata.json':
}}}
Here are the exact steps:
1. Create model instances in management shell
{{{
>>> from django.contrib.auth import get_user_model
>>> User = get_user_model()
>>> kal = User.objects.create_user('kal', '[email protected]', 'qwer1234')
>>> from licenses.models import AdobePhotoshopLicense
>>> l = AdobePhotoshopLicense.objects.create(user=kal,
license_key='12345')
}}}
2. Dump the data into a fixtures json
{{{
$ python manage.py dumpdata -o fixtures.json --format json --natural-
foreign --natural-primary auth licenses
}}}
3. Edit settings.py to switch to an empty database
{{{
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
#'NAME': 'nk_test',
'NAME': 'nk_test_2',
'USER': 'kal',
'HOST': '',
'PORT': 5432,
}
}
}}}
4. Run migrations on the new empty database
{{{
$ python manage.py migrate
}}}
5. Try to load the data from fixtures.json
{{{
$ python manage.py loaddata --format json fixtures.json
}}}
I have attached the `models.py` and `fixtures.json` files to the ticket.
Also note that this bug doesn't have to do with my use of the custom
`InheritanceManager`. I could let the `BaseLicense` model use the default
manager and still get the same bug.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/28972#comment:2>
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