Use '.remote_field' and '.model' in preference to '.rel' and '.to' when inspecting model fields.

rest_framework/compat.py

@@ -6,9 +6,13 @@ versions of Django/Python, and compatibility wrappers around optional packages.
 # flake8: noqa
 from __future__ import unicode_literals
 
+import inspect
+
 import django
+from django.apps import apps
 from django.conf import settings
-from django.db import connection, transaction
+from django.core.exceptions import ImproperlyConfigured
+from django.db import connection, models, transaction
 from django.template import Context, RequestContext, Template
 from django.utils import six
 from django.views.generic import View
@@ -88,6 +92,36 @@ def get_remote_field(field, **kwargs):
     return field.remote_field
 
 
+def _resolve_model(obj):
+    """
+    Resolve supplied `obj` to a Django model class.
+
+    `obj` must be a Django model class itself, or a string
+    representation of one.  Useful in situations like GH #1225 where
+    Django may not have resolved a string-based reference to a model in
+    another model's foreign key definition.
+
+    String representations should have the format:
+        'appname.ModelName'
+    """
+    if isinstance(obj, six.string_types) and len(obj.split('.')) == 2:
+        app_name, model_name = obj.split('.')
+        resolved_model = apps.get_model(app_name, model_name)
+        if resolved_model is None:
+            msg = "Django did not return a model for {0}.{1}"
+            raise ImproperlyConfigured(msg.format(app_name, model_name))
+        return resolved_model
+    elif inspect.isclass(obj) and issubclass(obj, models.Model):
+        return obj
+    raise ValueError("{0} is not a Django model".format(obj))
+
+
+def get_related_model(field):
+    if django.VERSION < (1, 9):
+        return _resolve_model(field.rel.to)
+    return field.remote_field.model
+
+
 # contrib.postgres only supported from 1.8 onwards.
 try:
     from django.contrib.postgres import fields as postgres_fields

rest_framework/utils/model_meta.py

@@ -5,15 +5,9 @@ relationships and their associated metadata.
 
 Usage: `get_field_info(model)` returns a `FieldInfo` instance.
 """
-import inspect
 from collections import OrderedDict, namedtuple
 
-from django.apps import apps
-from django.core.exceptions import ImproperlyConfigured
-from django.db import models
-from django.utils import six
-
-from rest_framework.compat import get_remote_field
+from rest_framework.compat import get_related_model, get_remote_field
 
 FieldInfo = namedtuple('FieldResult', [
     'pk',  # Model field instance
@@ -33,30 +27,6 @@ RelationInfo = namedtuple('RelationInfo', [
 ])
 
 
-def _resolve_model(obj):
-    """
-    Resolve supplied `obj` to a Django model class.
-
-    `obj` must be a Django model class itself, or a string
-    representation of one.  Useful in situations like GH #1225 where
-    Django may not have resolved a string-based reference to a model in
-    another model's foreign key definition.
-
-    String representations should have the format:
-        'appname.ModelName'
-    """
-    if isinstance(obj, six.string_types) and len(obj.split('.')) == 2:
-        app_name, model_name = obj.split('.')
-        resolved_model = apps.get_model(app_name, model_name)
-        if resolved_model is None:
-            msg = "Django did not return a model for {0}.{1}"
-            raise ImproperlyConfigured(msg.format(app_name, model_name))
-        return resolved_model
-    elif inspect.isclass(obj) and issubclass(obj, models.Model):
-        return obj
-    raise ValueError("{0} is not a Django model".format(obj))
-
-
 def get_field_info(model):
     """
     Given a model class, returns a `FieldInfo` instance, which is a
@@ -82,7 +52,7 @@ def _get_pk(opts):
 
     while rel and rel.parent_link:
         # If model is a child via multi-table inheritance, use parent's pk.
-        pk = rel.to._meta.pk
+        pk = get_related_model(pk)._meta.pk
         rel = get_remote_field(pk)
 
     return pk
@@ -108,7 +78,7 @@ def _get_forward_relationships(opts):
     for field in [field for field in opts.fields if field.serialize and get_remote_field(field)]:
         forward_relations[field.name] = RelationInfo(
             model_field=field,
-            related_model=_resolve_model(get_remote_field(field).to),
+            related_model=get_related_model(field),
             to_many=False,
             to_field=_get_to_field(field),
             has_through_model=False
@@ -118,7 +88,7 @@ def _get_forward_relationships(opts):
     for field in [field for field in opts.many_to_many if field.serialize]:
         forward_relations[field.name] = RelationInfo(
             model_field=field,
-            related_model=_resolve_model(get_remote_field(field).to),
+            related_model=get_related_model(field),
             to_many=True,
             # manytomany do not have to_fields
             to_field=None,

tests/test_utils.py

@@ -6,8 +6,8 @@ from django.test import TestCase, override_settings
 from django.utils import six
 
 import rest_framework.utils.model_meta
+from rest_framework.compat import _resolve_model
 from rest_framework.utils.breadcrumbs import get_breadcrumbs
-from rest_framework.utils.model_meta import _resolve_model
 from rest_framework.views import APIView
 from tests.models import BasicModel
 
@@ -166,16 +166,16 @@ class ResolveModelWithPatchedDjangoTests(TestCase):
 
     def setUp(self):
         """Monkeypatch get_model."""
-        self.get_model = rest_framework.utils.model_meta.apps.get_model
+        self.get_model = rest_framework.compat.apps.get_model
 
         def get_model(app_label, model_name):
             return None
 
-        rest_framework.utils.model_meta.apps.get_model = get_model
+        rest_framework.compat.apps.get_model = get_model
 
     def tearDown(self):
         """Revert monkeypatching."""
-        rest_framework.utils.model_meta.apps.get_model = self.get_model
+        rest_framework.compat.apps.get_model = self.get_model
 
     def test_blows_up_if_model_does_not_resolve(self):
         with self.assertRaises(ImproperlyConfigured):