#34807: importing `django.forms` causes circular import error
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Reporter: Collin Anderson | Owner: nobody
Type: Bug | Status: new
Component: Forms | Version: dev
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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circular import between forms and models and choices.
before 500e01073adda32d514962 you could import forms just fine.
{{{
git checkout 500e01073adda32d514962^
python3 -c"from django.db import models" # works fine
python3 -c"from django import forms" # works fine
}}}
but since 500e01073adda32d514962 this hasn't worked due to circular
import.
{{{
git checkout 500e01073adda32d514962
python3 -c"from django.db import models" # works fine
python3 -c"from django import forms" # fails:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "django/forms/__init__.py", line 6, in <module>
from django.forms.boundfield import * # NOQA
File "django/forms/boundfield.py", line 5, in <module>
from django.forms.widgets import MultiWidget, Textarea, TextInput
File "django/forms/widgets.py", line 15, in <module>
from django.utils.choices import normalize_choices
File "django/utils/choices.py", line 3, in <module>
from django.db.models.enums import ChoicesMeta
File "django/db/models/__init__.py", line 3, in <module>
from django.db.models.aggregates import * # NOQA
File "django/db/models/aggregates.py", line 5, in <module>
from django.db.models.expressions import Case, Func, Star, Value, When
File "django/db/models/expressions.py", line 12, in <module>
from django.db.models import fields
File "django/db/models/fields/__init__.py", line 18, in <module>
from django.utils.choices import CallableChoiceIterator,
normalize_choices
ImportError: cannot import name 'CallableChoiceIterator' from partially
initialized module 'django.utils.choices' (most likely due to a circular
import) (django/utils/choices.py)
python3 -c"from django.utils import choices" # also fails:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "django/utils/choices.py", line 3, in <module>
from django.db.models.enums import ChoicesMeta
File "django/db/models/__init__.py", line 3, in <module>
from django.db.models.aggregates import * # NOQA
File "django/db/models/aggregates.py", line 5, in <module>
from django.db.models.expressions import Case, Func, Star, Value, When
File "django/db/models/expressions.py", line 12, in <module>
from django.db.models import fields
File "django/db/models/fields/__init__.py", line 10, in <module>
from django import forms
File "django/forms/__init__.py", line 6, in <module>
from django.forms.boundfield import * # NOQA
File "django/forms/boundfield.py", line 5, in <module>
from django.forms.widgets import MultiWidget, Textarea, TextInput
File "django/forms/widgets.py", line 15, in <module>
from django.utils.choices import normalize_choices
ImportError: cannot import name 'normalize_choices' from partially
initialized module 'django.utils.choices' (most likely due to a circular
import) (django/utils/choices.py)
}}}
Models has always had a dependency on Forms, but now Models depends on
Forms depends on `utils.choices` which depend on
`models.enums.ChoicesMeta`
Summary of the circle: `django.forms` -> 'forms.widgets` ->
`django.utils.choices` -> `django.db.models.enums` -> `models.__init__` ->
`models.aggregates` -> `models.fields` -> `django.forms`
If `django.db.models` is imported before forms then it happens to import
fine because the order of imports happens to lines up perfectally, but
it's very very fragile. `models.__init__` -> `models.aggregates` ->
`models.fields` -> `django.forms` -> 'forms.widgets` ->
`django.utils.choices` -> `django.db.models.enums`.
--
Ticket URL: <https://code.djangoproject.com/ticket/34807>
Django <https://code.djangoproject.com/>
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