Django 上的 MakeMigration 错误 - ImportError: cannot import name 'FieldDoesNotExist' from 'django.db.models'

Question

添加新的 model 字段并运行 makemigrations 命令后出现以下错误：

ImportError：无法从“django.db.models”（/usr/local/lib/python3.7/site-packages/django/db/models/ init.py ）导入名称“FieldDoesNotExist”

这就是我的 models.py 的样子：

import uuid
from django.contrib.auth import get_user_model
from django.db import models
from django.urls import reverse

# Create your models here.
class Book(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    title = models.CharField(max_length=200)
    author = models.CharField(max_length=200)
    price = models.DecimalField(max_digits=6, decimal_places=2)
    cover = models.ImageField(upload_to='covers/', blank=True) # New Field

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('book_detail', args=[str(self.id)])

class Review(models.Model):
    book = models.ForeignKey(Book, on_delete=models.CASCADE, related_name='reviews')
    review = models.CharField(max_length=255)
    author = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)

    def __str__(self):
        return self.review

这是我的迁移文件的当前 state，我有两个。 0001_initial.py

# Generated by Django 3.0.8 on 2020-08-01 13:11

from django.db import migrations, models
import uuid


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='Book',
            fields=[
                ('id', models.UUIDField(default=uuid.uuid4, editable=False, primary_key=True, serialize=False)),
                ('title', models.CharField(max_length=200)),
                ('author', models.CharField(max_length=200)),
                ('price', models.DecimalField(decimal_places=2, max_digits=6)),
            ],
        ),
    ]

0002_review.py

# Generated by Django 3.0.8 on 2020-08-06 11:21

from django.conf import settings
from django.db import migrations, models
import django.db.models.deletion


class Migration(migrations.Migration):

    dependencies = [
        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
        ('books', '0001_initial'),
    ]

    operations = [
        migrations.CreateModel(
            name='Review',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('review', models.CharField(max_length=255)),
                ('author', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
                ('book', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='reviews', to='books.Book')),
            ],
        ),
    ]

这是运行 makemigration 命令后的异常回溯：

Exception in thread django-main-thread:
web_1  | Traceback (most recent call last):
web_1  |   File "/usr/local/lib/python3.7/threading.py", line 926, in _bootstrap_inner
web_1  |     self.run()
web_1  |   File "/usr/local/lib/python3.7/threading.py", line 870, in run
web_1  |     self._target(*self._args, **self._kwargs)
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/utils/autoreload.py", line 53, in wrapper
web_1  |     fn(*args, **kwargs)
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/core/management/commands/runserver.py", line 110, in inner_run
web_1  |     autoreload.raise_last_exception()
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/utils/autoreload.py", line 76, in raise_last_exception
web_1  |     raise _exception[1]
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 357, in execute
web_1  |     autoreload.check_errors(django.setup)()
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/utils/autoreload.py", line 53, in wrapper
web_1  |     fn(*args, **kwargs)
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/__init__.py", line 24, in setup
web_1  |     apps.populate(settings.INSTALLED_APPS)
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/apps/registry.py", line 114, in populate
web_1  |     app_config.import_models()
web_1  |   File "/usr/local/lib/python3.7/site-packages/django/apps/config.py", line 211, in import_models
web_1  |     self.models_module = import_module(models_module_name)
web_1  |   File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
web_1  |     return _bootstrap._gcd_import(name[level:], package, level)
web_1  |   File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
web_1  |   File "<frozen importlib._bootstrap>", line 983, in _find_and_load
web_1  |   File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
web_1  |   File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
web_1  |   File "<frozen importlib._bootstrap_external>", line 728, in exec_module
web_1  |   File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
web_1  |   File "/usr/local/lib/python3.7/site-packages/allauth/account/models.py", line 14, in <module>
web_1  |     from .adapter import get_adapter
web_1  |   File "/usr/local/lib/python3.7/site-packages/allauth/account/adapter.py", line 31, in <module>
web_1  |     from ..utils import (
web_1  |   File "/usr/local/lib/python3.7/site-packages/allauth/utils.py", line 15, in <module>
web_1  |     from django.db.models import FieldDoesNotExist, FileField
web_1  | ImportError: cannot import name 'FieldDoesNotExist' from 'django.db.models' (/usr/local/lib/python3.7/site-packages/django/db/models/__init__.py)

所以，我不知道究竟是什么导致了这个错误，并被困在这个阶段。 任何帮助将不胜感激。

Answer 1

您的django-allauth版本对FieldDoesNotExist的导入不正确。 正确的导入是：

from django.core.exceptions import FieldDoesNotExist

从django.db.models的导入可能适用于旧版本的 Django。

导入已在django-allauth版本 0.41.0 中修复。 如果您在requirements.txt或 pipenv 中更新django-allauth ，它应该可以解决问题。

Answer 2

就我而言， Django version 3.1.3与django-filter 2.0.0冲突。

类似的错误信息。 但是最后一行错误说是graphene-django 。 但是，在中间，它说django-filter 。 当我查看django-filter源文件时，错误地导入了FieldDoesNotExist 。 当我将django-filter升级到version 2.4.0时，问题解决了。

Answer 3

如我所见，您的版本为3.0.8 。 但对我来说，当我将requirements.txt从Django>=3.0.6 （使用最新的 3.1 Docker 图像）更改为Django==3.0.6时，它有所帮助，因为我使用的是最新的 3.1 版本，这似乎是兼容性问题在 3rd 方包上。

Answer 4

在 OP 的情况下，它是 django-allauth，在我的情况下是 django-filter。

检查错误日志中的最后一行，该行显示from django.db.models import FieldDoesNotExist, FileField的文件，并尝试升级 package。

在 OP 的情况下，错误日志行是这样的：

File "/usr/local/lib/python3.7/site-packages/allauth/utils.py"...

Answer 5

我的错误日志显示错误来自 rest_framework 应用程序（文件“/home/lkmandy/restapi-basics/lib/python3.8/site-packages/rest_framework/serializers.py”，第 25 行，in）。 但我无法升级它（如上述解决方案中所述），因为它只是我添加到我的 Django 项目中的一个应用程序。

对我有用的是使用 pip 升级我的虚拟环境中的所有包。 这是我使用的命令：

pip list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 pip install -U

来源： 如何使用 pip 升级所有 Python 包