[FIXED] Django TypeError: id() takes exactly one argument (0 given)

Issue

So I have been trying to implement a way to upload multiple images to a post. The way I did it is to have tables. One for the actual post, and one of the multiple images uploaded. I was planning to link them with a foreign key but it is not working. My terminal started throwing the error "TypeError: id() takes exactly one argument (0 given)" . It throws me this error whenever I migrate it.

I am not sure how to fix this.

MY code:

models.py

from django.db import models
from django.utils import timezone
from django.forms import ModelForm
from django.utils.text import slugify
from django.utils.crypto import get_random_string
from django.conf import settings

from PIL import Image

import os

DEFAULT_IMAGE_ID = 1

# Create your models here.
class Projects(models.Model):
    title = models.CharField(max_length=30)
    description = models.TextField(max_length=150)
    publish_date = models.DateTimeField(auto_now=False, auto_now_add=True)
    update_date = models.DateTimeField(auto_now=True, auto_now_add=False)
    slug = models.SlugField(unique=True)
    files = models.FileField(upload_to='files/', blank=True)
    images = models.ImageField(upload_to='images/', height_field = 'img_height', width_field = 'img_width',blank=True)
    img_height = models.PositiveIntegerField(default=600)
    img_width = models.PositiveIntegerField(default=300)
    #feature_images = models.ForeignKey(P_Images, on_delete=models.CASCADE, default=DEFAULT_IMAGE_ID)
    feature_images = models.AutoField(primary_key=True)

    def __str__(self):
        return self.title

    def save(self, *args, **kwargs):
        # Generates a random string 
        unique_string = get_random_string(length=32)

        # Combines title and unique string to slugify
        slugtext = self.title + "-" + "unique_id=-" + unique_string
        self.slug = slugify(slugtext)

        return super(Projects, self).save(*args, **kwargs)

class P_Images(models.Model):
    p_file = models.ImageField(upload_to='images/', blank=None)
    p_uploaded_at = models.DateTimeField(auto_now_add=True, auto_now=False)
    #fk_post = models
    fk_post = models.ForeignKey(Projects, on_delete=models.CASCADE)

The errorlog

Operations to perform:
  Apply all migrations: admin, auth, contenttypes, projects, sessions
Running migrations:
  Applying projects.0005_auto_20180823_0553...Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
    utility.execute()
  File "/home/erichardson/env01/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/erichardson/env01/lib/python3.6/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/core/management/base.py", line 335, in execute
    output = self.handle(*args, **options)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    fake_initial=fake_initial,
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/migrations/migration.py", line 122, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 216, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 525, in alter_field
    old_db_params, new_db_params, strict)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 630, in _alter_field
    new_default = self.effective_default(new_field)
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 218, in effective_default
    default = field.get_default()
  File "/home/erichardson/env01/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 775, in get_default
    return self._get_default()
TypeError: id() takes exactly one argument (0 given)

I use a MySQL database for this. This error started popping up after I updated my tables to be able to link with each other. I plan the fk_post of the P_Images to contain the feature_image value of Projects for the foreign key.

005_migration.py

import builtins
from django.db import migrations, models
import django.db.models.deletion


class Migration(migrations.Migration):

    dependencies = [
        ('projects', '0004_auto_20180823_0547'),
    ]

    operations = [
        migrations.AlterField(
            model_name='p_images',
            name='fk_post',
            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='projects.Projects'),
        ),
        migrations.AlterField(
            model_name='projects',
            name='feature_images',
            field=models.IntegerField(default=builtins.id),
        ),
    ]

please let me know if the migration.py tells you something or nothing.

Solution

You have something very bizarre in your migration:

models.IntegerField(default=builtins.id)

This is referring to the builtin id function, which requires an argument because it returns the internal ID of an object in Python. It has nothing to do with database IDs, and doesn't belong here at all. I can only guess that you were asked for a default when creating the migration and you just typed in id.

You should delete that default from the migration, but that may make it unable to execute. You could also try a default of 0, which makes sense there; but your actual models code shows that field as the primary key, so you presumably have another subsequent migration that changes the field again; and 0 wouldn't work as a pk.

If you're still in development and don't have any data you need to keep, I would suggest deleting your database and migrations completely and starting again with makemigrations.

Answered By - Daniel Roseman