Loading choices from utils.py results in unexpected error: TypeError: 'CharField' object is not iterable in Django
Question:
I have a models.py file in Django, and it was working perfectly. I have an extensive model named Media, and since it contains quite some Fields with elaborate choices in nested tuples, I decided to move these nested tuples to an utils.py file located in the same app. I found that it is working for all columns in my Media model, except for one. It is shown below:
#This was how it was initially and working:
#Umbrella
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF")
)
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
second_umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True) #Problematic?
Changed it to:
utils.py:
#Umbrella
def UMBRELLA():
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF"))
return(UMBRELLA)
models.py:
from database.utils import *
umbrella=UMBRELLA()
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=umbrella, default='Undefined', null=True, blank=True) #This one is not problematic
second_umbrella = models.CharField(max_length=20, choices=umbrella, default='Undefined', null=True, blank=True) #This one is problematic
The strange thing here is that if I only change (first) umbrella choiches to umbrella from utils.py it works fine. However, if i change choices from second_umbrella to umbrella from utils.py it crashes?? I meticulously checked the db.sqlite3 with django admin, but the choices are correct in there as originally defined, and exactly similar for both fields (umbrella1 and umbrella2). I can’t understand why it works in one case and not in the other whilst they are exactly similar. It also worked out of the box for all other fields for which I migrated the choices to utils.py. Error prompts on just runserver or makemigrations.
Errorlog:
Traceback (most recent call last):
File "C:directorymanage.py", line 22, in <module>
main()
File "C:directorymanage.py", line 18, in main
execute_from_command_line(sys.argv)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagement__init__.py", line 446, in execute_from_command_line
utility.execute()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagement__init__.py", line 440, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 402, in run_from_argv
self.execute(*args, **cmd_options)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 443, in execute
self.check()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 475, in check
all_issues = checks.run_checks(
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksregistry.py", line 88, in run_checks
new_errors = check(app_configs=app_configs, databases=databases)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksurls.py", line 14, in check_url_config
return check_resolver(resolver)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksurls.py", line 24, in check_resolver
return check_method()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 476, in check
for pattern in self.url_patterns:
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoutilsfunctional.py", line 57, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 690, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoutilsfunctional.py", line 57, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 683, in urlconf_module
return import_module(self.urlconf_name)
File "C:UsersMaAppDataLocalProgramsPythonPython310libimportlib__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 883, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "C:directorydirectoryurls.py", line 21, in <module>
path('database/', include("database.urls")),
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsconf.py", line 38, in include
urlconf_module = import_module(urlconf_module)
File "C:UsersMaAppDataLocalProgramsPythonPython310libimportlib__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 883, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "C:directorydatabaseurls.py", line 3, in <module>
from . import views
File "C:directorydatabaseviews.py", line 2, in <module>
from database.forms import MediaForm
packagesdjangoformsmodels.py", line 224, in fields_for_model _C:directorydatabaseforms.py", line 4, in <module>
formfield = f.formfield(**kwargs)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoformsmodels.py", line 306, in __new__ibsite-ds = fields_for_model(
packagesdjangodbmodelsfields__init__.py", line 1211, in foribsite-packagesdjangoformsmodels.py", line 224, in fields_for_modelmfield field = f.formfield(**kwargs)
return super().formfield(**defaults) ibsite-packagesdjangodbmodelsfields__init__.py", line 1211, in formfield
File "C:UsersMaAppDataLocalProgramsPythonPython310l, in formfield ibsite-packagesdjangodbmodelsfields__init__.py", line 1026, in formfield
return super().formfield(**defaults) _blank)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangodbmodelsfields__init__.py", line 962, in get_choicesibsite-packagesdjangodbmodelsfields__init__.py", line 1026, in formfield
defaults["choices"] = self.get_choices(include_blank=includeppDjango_Databasedirectory> _blank)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangodbmodelsfields__init__.py", line 962, in get_choices
choices = list(self.choices)
TypeError: 'CharField' object is not iterable
Since forms.py is mentioned in the error message I will also post that one:
from django.forms import ModelForm
from database.models import Media
class MediaForm(ModelForm):
class Meta:
model = Media
fields='__all__'
What can I do? I already tried to change the second_umbrella column to another name and make new migration, but the same error remains, and it more seems like a bug somehow than an actual error.
Answers:
I think the over-engineer is the problem, and probablly the choices can’t be dinamically defined, or at least is not kosher
why not use this:
utils.py:
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF"))
models.py:
from database.utils import *
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
second_umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
so import only the constant, and don’t use a innecesary function (and 3 lines less of code)
I have a models.py file in Django, and it was working perfectly. I have an extensive model named Media, and since it contains quite some Fields with elaborate choices in nested tuples, I decided to move these nested tuples to an utils.py file located in the same app. I found that it is working for all columns in my Media model, except for one. It is shown below:
#This was how it was initially and working:
#Umbrella
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF")
)
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
second_umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True) #Problematic?
Changed it to:
utils.py:
#Umbrella
def UMBRELLA():
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF"))
return(UMBRELLA)
models.py:
from database.utils import *
umbrella=UMBRELLA()
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=umbrella, default='Undefined', null=True, blank=True) #This one is not problematic
second_umbrella = models.CharField(max_length=20, choices=umbrella, default='Undefined', null=True, blank=True) #This one is problematic
The strange thing here is that if I only change (first) umbrella choiches to umbrella from utils.py it works fine. However, if i change choices from second_umbrella to umbrella from utils.py it crashes?? I meticulously checked the db.sqlite3 with django admin, but the choices are correct in there as originally defined, and exactly similar for both fields (umbrella1 and umbrella2). I can’t understand why it works in one case and not in the other whilst they are exactly similar. It also worked out of the box for all other fields for which I migrated the choices to utils.py. Error prompts on just runserver or makemigrations.
Errorlog:
Traceback (most recent call last):
File "C:directorymanage.py", line 22, in <module>
main()
File "C:directorymanage.py", line 18, in main
execute_from_command_line(sys.argv)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagement__init__.py", line 446, in execute_from_command_line
utility.execute()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagement__init__.py", line 440, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 402, in run_from_argv
self.execute(*args, **cmd_options)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 443, in execute
self.check()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocoremanagementbase.py", line 475, in check
all_issues = checks.run_checks(
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksregistry.py", line 88, in run_checks
new_errors = check(app_configs=app_configs, databases=databases)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksurls.py", line 14, in check_url_config
return check_resolver(resolver)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangocorechecksurls.py", line 24, in check_resolver
return check_method()
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 476, in check
for pattern in self.url_patterns:
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoutilsfunctional.py", line 57, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 690, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoutilsfunctional.py", line 57, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsresolvers.py", line 683, in urlconf_module
return import_module(self.urlconf_name)
File "C:UsersMaAppDataLocalProgramsPythonPython310libimportlib__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 883, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "C:directorydirectoryurls.py", line 21, in <module>
path('database/', include("database.urls")),
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangourlsconf.py", line 38, in include
urlconf_module = import_module(urlconf_module)
File "C:UsersMaAppDataLocalProgramsPythonPython310libimportlib__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 883, in exec_module
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "C:directorydatabaseurls.py", line 3, in <module>
from . import views
File "C:directorydatabaseviews.py", line 2, in <module>
from database.forms import MediaForm
packagesdjangoformsmodels.py", line 224, in fields_for_model _C:directorydatabaseforms.py", line 4, in <module>
formfield = f.formfield(**kwargs)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangoformsmodels.py", line 306, in __new__ibsite-ds = fields_for_model(
packagesdjangodbmodelsfields__init__.py", line 1211, in foribsite-packagesdjangoformsmodels.py", line 224, in fields_for_modelmfield field = f.formfield(**kwargs)
return super().formfield(**defaults) ibsite-packagesdjangodbmodelsfields__init__.py", line 1211, in formfield
File "C:UsersMaAppDataLocalProgramsPythonPython310l, in formfield ibsite-packagesdjangodbmodelsfields__init__.py", line 1026, in formfield
return super().formfield(**defaults) _blank)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangodbmodelsfields__init__.py", line 962, in get_choicesibsite-packagesdjangodbmodelsfields__init__.py", line 1026, in formfield
defaults["choices"] = self.get_choices(include_blank=includeppDjango_Databasedirectory> _blank)
File "C:UsersMaAppDataLocalProgramsPythonPython310libsite-packagesdjangodbmodelsfields__init__.py", line 962, in get_choices
choices = list(self.choices)
TypeError: 'CharField' object is not iterable
Since forms.py is mentioned in the error message I will also post that one:
from django.forms import ModelForm
from database.models import Media
class MediaForm(ModelForm):
class Meta:
model = Media
fields='__all__'
What can I do? I already tried to change the second_umbrella column to another name and make new migration, but the same error remains, and it more seems like a bug somehow than an actual error.
I think the over-engineer is the problem, and probablly the choices can’t be dinamically defined, or at least is not kosher
why not use this:
utils.py:
UMBRELLA = (
("DH", "DH"),
("SE", "SE"),
("PA", "PA"),
("PF", "PF"))
models.py:
from database.utils import *
class Media(models.Model):
umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
second_umbrella = models.CharField(max_length=20, choices=UMBRELLA, default='Undefined', null=True, blank=True)
so import only the constant, and don’t use a innecesary function (and 3 lines less of code)