Fix ModelSerializer to use the model field's error messages

rest_framework/serializers.py

@@ -848,6 +848,9 @@ class ModelSerializer(Serializer):
         if model_field.help_text is not None:
             kwargs['help_text'] = model_field.help_text
 
+        if model_field.error_messages is not None:
+            kwargs['error_messages'] = model_field.error_messages
+
         # TODO: TypedChoiceField?
         if model_field.flatchoices:  # This ModelField contains choices
             kwargs['choices'] = model_field.flatchoices

rest_framework/tests/test_serializer.py

@@ -1840,3 +1840,37 @@ class BoolenFieldTypeTest(TestCase):
         '''
         bfield = self.serializer.get_fields()['started']
         self.assertEqual(type(bfield), fields.BooleanField)
+
+
+class ErrorMessagesOnAutogeneratedFieldsTests(TestCase):
+
+    def setUp(self):
+        class EMOAFModel(RESTFrameworkModel):
+            char_field = models.CharField(blank=False, max_length=5, error_messages={
+                'required': 'required',
+                'max_length': 'max_length %(limit_value)d',
+            })
+
+        class EMOAFSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = EMOAFModel
+
+        self.serializer_class = EMOAFSerializer
+
+    def error_test(self, data, expected_message):
+        serializer = self.serializer_class(data=data)
+        self.assertEqual(serializer.is_valid(), False)
+        self.assertEqual(len(serializer.errors), 1)
+
+        for (field_name, message) in serializer.errors.items():
+            self.assertEqual('char_field', field_name)
+            self.assertEqual(expected_message, message[0])
+
+    def test_required(self):
+        self.error_test({}, 'required')
+
+    def test_required(self):
+        self.error_test({'char_field': None}, 'required')
+
+    def test_max_length(self):
+        self.error_test({'char_field': 'abcdef'}, 'max_length 5')