Commit 108b8bf8 authored by Claude Paroz's avatar Claude Paroz
Browse files

Fixed #24007 -- Ensure apps registry's ready before unpickling models 

This prevents AppRegistryNotReady errors when unpickling Django
models from an external script.
parent f3eed951

django/db/models/base.py

+2 −0
Original line number Diff line number Diff line
@@ -1658,6 +1658,8 @@ def model_unpickle(model_id, attrs, factory): 
    Used to unpickle Model subclasses with deferred fields.

    """

    if isinstance(model_id, tuple):

        if not apps.ready:

            apps.populate(settings.INSTALLED_APPS)

        model = apps.get_model(*model_id)

    else:

        # Backwards compat - the model was cached directly in earlier versions.

docs/releases/1.7.2.txt

+4 −0
Original line number Diff line number Diff line
@@ -151,3 +151,7 @@ Bugfixes 
  (:ticket:`23975`).



* Made admin system checks run for custom ``AdminSite``\s (:ticket:`23497`).



* Ensured the app registry is fully populated when unpickling models. When an

  external script (like a queueing infrastructure) reloads pickled models, it

  could crash with an ``AppRegistryNotReady`` exception (:ticket:`24007`).

tests/model_regress/test_pickle.py

+35 −0
Original line number Diff line number Diff line 
import datetime

import pickle

import subprocess

import tempfile

import warnings



from django.db import models, DJANGO_VERSION_PICKLE_KEY
@@ -6,6 +9,8 @@ from django.test import TestCase 
from django.utils.encoding import force_text

from django.utils.version import get_major_version, get_version



from .models import Article





class ModelPickleTestCase(TestCase):

    def test_missing_django_version_unpickling(self):
@@ -51,3 +56,33 @@ class ModelPickleTestCase(TestCase): 
                "Pickled model instance's Django version %s does not "

                "match the current version %s."

                % (str(float(get_major_version()) - 0.1), get_version()))



    def test_unpickling_when_appregistrynotready(self):

        """

        #24007 -- Verifies that a pickled model can be unpickled without having

        to manually setup the apps registry beforehand.

        """

        script_template = """#!/usr/bin/env python

import pickle



from django.conf import settings



data = %r



settings.configure(DEBUG=False, INSTALLED_APPS=('model_regress',), SECRET_KEY = "blah")

article = pickle.loads(data)

print(article.headline)"""

        a = Article.objects.create(

            headline="Some object",

            pub_date=datetime.datetime.now(),

            article_text="This is an article",

        )



        with tempfile.NamedTemporaryFile(mode='w+', suffix=".py", dir='.', delete=True) as script:

            script.write(script_template % pickle.dumps(a))

            script.flush()

            try:

                result = subprocess.check_output(['python', script.name])

            except subprocess.CalledProcessError:

                self.fail("Unable to reload model pickled data")

        self.assertEqual(result.strip().decode(), "Some object")