From edc05d0896431b3d664e54234923113662bb200b Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Wed, 18 Dec 2019 11:02:59 +0200
Subject: [PATCH] Handle missing Meta properly

---
 rest_framework/serializers.py  | 17 ++++++++++-------
 tests/test_model_serializer.py |  8 ++++++++
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 727fd37fd..f3a24da63 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -862,15 +862,13 @@ class ModelSerializerMetaclass(SerializerMetaclass):
 
     @classmethod
     def _get_fields(cls, new_class):
-        # XXX
+        # ModelSerializer itself and customized subclasses like
+        # HyperlinkedModelSerializer are never instantiated directly,
+        # and don't have a Meta. For these, the base_fields is None,
+        # and an error is raised if it's attempted to be used.
         if not hasattr(new_class, 'Meta'):
-            return OrderedDict()
+            return None
 
-        assert hasattr(new_class, 'Meta'), (
-            'Class {serializer_class} missing "Meta" attribute'.format(
-                serializer_class=new_class.__name__
-            )
-        )
         assert hasattr(new_class.Meta, 'model'), (
             'Class {serializer_class} missing "Meta.model" attribute'.format(
                 serializer_class=new_class.__name__
@@ -1097,6 +1095,11 @@ class ModelSerializer(Serializer, metaclass=ModelSerializerMetaclass):
         Return the dict of field names -> field instances that should be
         used for `self.fields` when instantiating the serializer.
         """
+        assert self.base_fields is not None, (
+            'Class {serializer_class} missing "Meta" attribute'.format(
+                serializer_class=self.__class__.__name__
+            )
+        )
         return copy.deepcopy(self.base_fields)
 
     # Methods for determining the set of field names to include...
diff --git a/tests/test_model_serializer.py b/tests/test_model_serializer.py
index 852b5a180..87c218a70 100644
--- a/tests/test_model_serializer.py
+++ b/tests/test_model_serializer.py
@@ -151,6 +151,14 @@ class TestModelSerializer(TestCase):
                     model = AbstractModel
                     fields = ('afield',)
 
+    def test_missing_meta(self):
+        class TestSerializer(serializers.ModelSerializer):
+            text = serializers.CharField()
+
+        msginitial = 'Class TestSerializer missing "Meta" attribute'
+        with self.assertRaisesMessage(AssertionError, msginitial):
+            TestSerializer().fields
+
 
 class TestRegularFieldMappings(TestCase):
     def test_regular_fields(self):