Fix dict with extra keys (#490)

* Fix dict with extra keys (#489), fix #488

* Fix PR number

* Fix Config of MyModel not to inherit BaseConfig

HISTORY.rst

@@ -6,6 +6,7 @@ History
 v0.25 (unreleased)
 ..................
 * Improve documentation on self-referencing models and annotations, #487 by @theenglishway
+* fix ``.dict()`` with extra keys, #490 by @JaewonKim
 
 v0.24 (2019-04-23)
 ..................

pydantic/main.py

@@ -289,7 +289,7 @@ class BaseModel(metaclass=MetaModel):
 
     def _get_key_factory(self, by_alias: bool) -> Callable[..., str]:
         if by_alias:
-            return lambda fields, key: fields[key].alias
+            return lambda fields, key: fields[key].alias if key in fields else key
 
         return lambda _, key: key
 

tests/test_main.py

@@ -3,7 +3,7 @@ from typing import Any, ClassVar, List
 
 import pytest
 
-from pydantic import BaseModel, Extra, NoneBytes, NoneStr, Required, ValidationError, constr
+from pydantic import BaseModel, Extra, NoneBytes, NoneStr, Required, Schema, ValidationError, constr
 
 
 def test_success():
@@ -576,3 +576,15 @@ def test_dir_fields():
     assert "json" in dir(m)
     assert "attribute_a" in dir(m)
     assert "attribute_b" in dir(m)
+
+
+def test_dict_with_extra_keys():
+    class MyModel(BaseModel):
+        a: str = Schema(None, alias='alias_a')
+
+        class Config:
+            extra = Extra.allow
+
+    m = MyModel(extra_key='extra')
+    assert m.dict() == {'a': None, 'extra_key': 'extra'}
+    assert m.dict(by_alias=True) == {'alias_a': None, 'extra_key': 'extra'}