Merge pull request #2267 from tomchristie/better-misconfigured-serializer-errors

Better errors when serializer has incorrectly named field.

rest_framework/fields.py

@@ -274,7 +274,23 @@ class Field(object):
         Given the *outgoing* object instance, return the primitive value
         that should be used for this field.
         """
-        return get_attribute(instance, self.source_attrs)
+        try:
+            return get_attribute(instance, self.source_attrs)
+        except (KeyError, AttributeError) as exc:
+            msg = (
+                'Got {exc_type} when attempting to get a value for field '
+                '`{field}` on serializer `{serializer}`.\nThe serializer '
+                'field might be named incorrectly and not match '
+                'any attribute or key on the `{instance}` instance.\n'
+                'Original exception text was: {exc}.'.format(
+                    exc_type=type(exc).__name__,
+                    field=self.field_name,
+                    serializer=self.parent.__class__.__name__,
+                    instance=instance.__class__.__name__,
+                    exc=exc
+                )
+            )
+            raise type(exc)(msg)
 
     def get_default(self):
         """

tests/test_serializer.py

+from __future__ import unicode_literals
 from rest_framework import serializers
 import pytest
 
@@ -175,3 +176,24 @@ class TestStarredSource:
         instance = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
         serializer = self.Serializer(instance)
         assert serializer.data == self.data
+
+
+class TestIncorrectlyConfigured:
+    def test_incorrect_field_name(self):
+        class ExampleSerializer(serializers.Serializer):
+            incorrect_name = serializers.IntegerField()
+
+        class ExampleObject:
+            def __init__(self):
+                self.correct_name = 123
+
+        instance = ExampleObject()
+        serializer = ExampleSerializer(instance)
+        with pytest.raises(AttributeError) as exc_info:
+            serializer.data
+        msg = str(exc_info.value)
+        assert msg.startswith(
+            "Got AttributeError when attempting to get a value for field `incorrect_name` on serializer `ExampleSerializer`.\n"
+            "The serializer field might be named incorrectly and not match any attribute or key on the `ExampleObject` instance.\n"
+            "Original exception text was:"
+        )