From a3d9ad16e7f0f91efd25513951c80c49ce665b4b Mon Sep 17 00:00:00 2001
From: jakeb <jakeb@ab180.co>
Date: Thu, 25 Apr 2019 19:50:58 +0900
Subject: [PATCH] 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        |  1 +
 pydantic/main.py   |  2 +-
 tests/test_main.py | 14 +++++++++++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/HISTORY.rst b/HISTORY.rst
index dff3e4e..805c294 100644
--- a/HISTORY.rst
+++ b/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)
 ..................
diff --git a/pydantic/main.py b/pydantic/main.py
index dfa2b21..6873842 100644
--- a/pydantic/main.py
+++ b/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
 
diff --git a/tests/test_main.py b/tests/test_main.py
index d157bdd..babe37d 100644
--- a/tests/test_main.py
+++ b/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'}