Enforce field_name != source

rest_framework/fields.py

@@ -160,6 +160,17 @@ class Field(object):
         """
         Setup the context for the field instance.
         """
+
+        # In order to enforce a consistent style, we error if a redundant
+        # 'source' argument has been used. For example:
+        # my_field = serializer.CharField(source='my_field')
+        assert self._kwargs.get('source') != field_name, (
+            "It is redundant to specify `source='%s'` on field '%s' in "
+            "serializer '%s', as it is the same the field name. "
+            "Remove the `source` keyword argument." %
+            (field_name, self.__class__.__name__, parent.__class__.__name__)
+        )
+
         self.field_name = field_name
         self.parent = parent
         self.root = root

tests/test_fields.py

 from decimal import Decimal
 from django.utils import timezone
-from rest_framework import fields
+from rest_framework import fields, serializers
 import datetime
 import django
 import pytest
@@ -69,6 +69,17 @@ class TestFieldOptions:
         output = field.run_validation()
         assert output is 123
 
+    def test_redundant_source(self):
+        class ExampleSerializer(serializers.Serializer):
+            example_field = serializers.CharField(source='example_field')
+        with pytest.raises(AssertionError) as exc_info:
+            ExampleSerializer()
+        assert str(exc_info.value) == (
+            "It is redundant to specify `source='example_field'` on field "
+            "'CharField' in serializer 'ExampleSerializer', as it is the "
+            "same the field name. Remove the `source` keyword argument."
+        )
+
 
 # Tests for field input and output values.
 # ----------------------------------------