From f683bba6f6813e353c9391e993c015d74d77a1af Mon Sep 17 00:00:00 2001
From: Andrew Nester <andrew.nester.dev@gmail.com>
Date: Thu, 30 Jun 2016 14:22:10 +0300
Subject: [PATCH] [1.10.x] Fixed #25292 -- Fixed crash in
ManyToManyField.through_fields check.
Backport of baff4dd37dabfef1ff939513fa45124382b57bf8 from master
---
django/db/models/base.py | 4 ++++
.../invalid_models_tests/test_relative_fields.py | 16 ++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/django/db/models/base.py b/django/db/models/base.py
index 52a96c3ffe..59bf98c494 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -1685,6 +1685,10 @@ class Model(six.with_metaclass(ModelBase)):
)
for f in cls._meta.local_many_to_many:
+ # Skip nonexistent models.
+ if isinstance(f.remote_field.through, six.string_types):
+ continue
+
# Check if auto-generated name for the M2M field is too long
# for the database.
for m2m in f.remote_field.through._meta.local_fields:
diff --git a/tests/invalid_models_tests/test_relative_fields.py b/tests/invalid_models_tests/test_relative_fields.py
index 8b95cf3e18..b9a61f8f64 100644
--- a/tests/invalid_models_tests/test_relative_fields.py
+++ b/tests/invalid_models_tests/test_relative_fields.py
@@ -307,6 +307,22 @@ class RelativeFieldTests(SimpleTestCase):
]
self.assertEqual(errors, expected)
+ def test_missing_relationship_model_on_model_check(self):
+ class Person(models.Model):
+ pass
+
+ class Group(models.Model):
+ members = models.ManyToManyField('Person', through='MissingM2MModel')
+
+ self.assertEqual(Group.check(), [
+ Error(
+ "Field specifies a many-to-many relation through model "
+ "'MissingM2MModel', which has not been installed.",
+ obj=Group._meta.get_field('members'),
+ id='fields.E331',
+ ),
+ ])
+
@isolate_apps('invalid_models_tests')
def test_many_to_many_through_isolate_apps_model(self):
"""