1 files changed, 10 insertions, 4 deletions
diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index c83ee5ec..fc14184c 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -15,10 +15,12 @@ import warnings
 from django.core import validators
 from django.core.exceptions import ValidationError
 from django.conf import settings
+from django.db.models.fields import BLANK_CHOICE_DASH
 from django import forms
 from django.forms import widgets
 from django.utils.encoding import is_protected_type
 from django.utils.translation import ugettext_lazy as _
+from django.utils.datastructures import SortedDict
 
 from rest_framework import ISO_8601
 from rest_framework.compat import timezone, parse_date, parse_datetime, parse_time
@@ -50,7 +52,7 @@ def get_component(obj, attr_name):
     return that attribute on the object.
     """
     if isinstance(obj, dict):
-        val = obj[attr_name]
+        val = obj.get(attr_name)
     else:
         val = getattr(obj, attr_name)
 
@@ -170,7 +172,11 @@ class Field(object):
         elif hasattr(value, '__iter__') and not isinstance(value, (dict, six.string_types)):
             return [self.to_native(item) for item in value]
         elif isinstance(value, dict):
-            return dict(map(self.to_native, (k, v)) for k, v in value.items())
+            # Make sure we preserve field ordering, if it exists
+            ret = SortedDict()
+            for key, val in value.items():
+                ret[key] = self.to_native(val)
+            return ret
         return smart_text(value)
 
     def attributes(self):
@@ -377,7 +383,6 @@ class URLField(CharField):
     type_name = 'URLField'
 
     def __init__(self, **kwargs):
-        kwargs['max_length'] = kwargs.get('max_length', 200)
         kwargs['validators'] = [validators.URLValidator()]
         super(URLField, self).__init__(**kwargs)
 
@@ -386,7 +391,6 @@ class SlugField(CharField):
     type_name = 'SlugField'
 
     def __init__(self, *args, **kwargs):
-        kwargs['max_length'] = kwargs.get('max_length', 50)
         super(SlugField, self).__init__(*args, **kwargs)
 
 
@@ -402,6 +406,8 @@ class ChoiceField(WritableField):
     def __init__(self, choices=(), *args, **kwargs):
         super(ChoiceField, self).__init__(*args, **kwargs)
         self.choices = choices
+        if not self.required:
+            self.choices = BLANK_CHOICE_DASH + self.choices
 
     def _get_choices(self):
         return self._choices