From 108b8bf852c76855ed98f5abe55db1da845598e7 Mon Sep 17 00:00:00 2001
From: Claude Paroz <claude@2xlibre.net>
Date: Wed, 17 Dec 2014 17:25:28 +0100
Subject: [PATCH] Fixed #24007 -- Ensure apps registry's ready before
unpickling models
This prevents AppRegistryNotReady errors when unpickling Django
models from an external script.
---
django/db/models/base.py | 2 ++
docs/releases/1.7.2.txt | 4 ++++
tests/model_regress/test_pickle.py | 35 ++++++++++++++++++++++++++++++
3 files changed, 41 insertions(+)
diff --git a/django/db/models/base.py b/django/db/models/base.py
index af007d77ce..d0c1b7ad16 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -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.
diff --git a/docs/releases/1.7.2.txt b/docs/releases/1.7.2.txt
index 88f3d3e1d8..47a56084d0 100644
--- a/docs/releases/1.7.2.txt
+++ b/docs/releases/1.7.2.txt
@@ -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`).
diff --git a/tests/model_regress/test_pickle.py b/tests/model_regress/test_pickle.py
index 8dc90893bf..ab70b4ec91 100644
--- a/tests/model_regress/test_pickle.py
+++ b/tests/model_regress/test_pickle.py
@@ -1,4 +1,7 @@
+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")