Dropped Python 2 compatibility. (#6615)

Thanks to Jon Dufresne (@jdufresne) for review.

Co-authored-by: Asif Saif Uddin <auvipy@gmail.com>
Co-authored-by: Rizwan Mansuri <Rizwan@webbyfox.com>

Author: 3 people

.travis.yml

@@ -4,7 +4,6 @@ dist: xenial
 matrix:
     fast_finish: true
     include:
-      - { python: "2.7", env: DJANGO=1.11 }
 
       - { python: "3.4", env: DJANGO=1.11 }
       - { python: "3.4", env: DJANGO=2.0 }
@@ -26,8 +25,8 @@ matrix:
       - { python: "3.7", env: DJANGO=master }
 
       - { python: "3.7", env: TOXENV=base }
-      - { python: "2.7", env: TOXENV=lint }
-      - { python: "2.7", env: TOXENV=docs }
+      - { python: "3.7", env: TOXENV=lint }
+      - { python: "3.7", env: TOXENV=docs }
 
       - python: "3.7"
         env: TOXENV=dist

README.md

@@ -53,7 +53,7 @@ There is a live example API for testing purposes, [available here][sandbox].
 
 # Requirements
 
-* Python (2.7, 3.4, 3.5, 3.6, 3.7)
+* Python (3.4, 3.5, 3.6, 3.7)
 * Django (1.11, 2.0, 2.1, 2.2)
 
 We **highly recommend** and only officially support the latest patch release of

docs/api-guide/fields.md

@@ -629,7 +629,7 @@ Our `ColorField` class above currently does not perform any data validation.
 To indicate invalid data, we should raise a `serializers.ValidationError`, like so:
 
     def to_internal_value(self, data):
-        if not isinstance(data, six.text_type):
+        if not isinstance(data, str):
             msg = 'Incorrect type. Expected a string, but got %s'
             raise ValidationError(msg % type(data).__name__)
 
@@ -653,7 +653,7 @@ The `.fail()` method is a shortcut for raising `ValidationError` that takes a me
     }
 
     def to_internal_value(self, data):
-        if not isinstance(data, six.text_type):
+        if not isinstance(data, str):
             self.fail('incorrect_type', input_type=type(data).__name__)
 
         if not re.match(r'^rgb\([0-9]+,[0-9]+,[0-9]+\)$', data):

rest_framework/authentication.py

@@ -1,14 +1,11 @@
 """
 Provides various authentication policies.
 """
-from __future__ import unicode_literals
-
 import base64
 import binascii
 
 from django.contrib.auth import authenticate, get_user_model
 from django.middleware.csrf import CsrfViewMiddleware
-from django.utils.six import text_type
 from django.utils.translation import ugettext_lazy as _
 
 from rest_framework import HTTP_HEADER_ENCODING, exceptions
@@ -21,7 +18,7 @@ def get_authorization_header(request):
     Hide some test client ickyness where the header can be unicode.
     """
     auth = request.META.get('HTTP_AUTHORIZATION', b'')
-    if isinstance(auth, text_type):
+    if isinstance(auth, str):
         # Work around django test client oddness
         auth = auth.encode(HTTP_HEADER_ENCODING)
     return auth
@@ -33,7 +30,7 @@ def _reject(self, request, reason):
         return reason
 
 
-class BaseAuthentication(object):
+class BaseAuthentication:
     """
     All authentication classes should extend BaseAuthentication.
     """

rest_framework/authtoken/management/commands/drf_create_token.py

@@ -38,8 +38,8 @@ def handle(self, *args, **options):
             token = self.create_user_token(username, reset_token)
         except UserModel.DoesNotExist:
             raise CommandError(
-                'Cannot create the Token: user {0} does not exist'.format(
+                'Cannot create the Token: user {} does not exist'.format(
                     username)
             )
         self.stdout.write(
-            'Generated token {0} for user {1}'.format(token.key, username))
+            'Generated token {} for user {}'.format(token.key, username))

rest_framework/authtoken/migrations/0001_initial.py

@@ -1,6 +1,3 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 from django.conf import settings
 from django.db import migrations, models
 

rest_framework/authtoken/migrations/0002_auto_20160226_1747.py

@@ -1,6 +1,3 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 from django.conf import settings
 from django.db import migrations, models
 

rest_framework/authtoken/models.py

@@ -3,11 +3,9 @@
 
 from django.conf import settings
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 
 
-@python_2_unicode_compatible
 class Token(models.Model):
     """
     The default authorization token model.
@@ -32,7 +30,7 @@ class Meta:
     def save(self, *args, **kwargs):
         if not self.key:
             self.key = self.generate_key()
-        return super(Token, self).save(*args, **kwargs)
+        return super().save(*args, **kwargs)
 
     def generate_key(self):
         return binascii.hexlify(os.urandom(20)).decode()

rest_framework/compat.py

@@ -2,23 +2,13 @@
 The `compat` module provides support for backwards compatibility with older
 versions of Django/Python, and compatibility wrappers around optional packages.
 """
-
-from __future__ import unicode_literals
-
 import sys
+from collections.abc import Mapping, MutableMapping  # noqa
 
 from django.conf import settings
 from django.core import validators
-from django.utils import six
 from django.views.generic import View
 
-try:
-    # Python 3
-    from collections.abc import Mapping, MutableMapping   # noqa
-except ImportError:
-    # Python 2.7
-    from collections import Mapping, MutableMapping   # noqa
-
 try:
     from django.urls import (  # noqa
         URLPattern,
@@ -36,11 +26,6 @@
 except ImportError:
     ProhibitNullCharactersValidator = None
 
-try:
-    from unittest import mock
-except ImportError:
-    mock = None
-
 
 def get_original_route(urlpattern):
     """
@@ -89,23 +74,6 @@ def make_url_resolver(regex, urlpatterns):
         return URLResolver(regex, urlpatterns)
 
 
-def unicode_repr(instance):
-    # Get the repr of an instance, but ensure it is a unicode string
-    # on both python 3 (already the case) and 2 (not the case).
-    if six.PY2:
-        return repr(instance).decode('utf-8')
-    return repr(instance)
-
-
-def unicode_to_repr(value):
-    # Coerce a unicode string to the correct repr return type, depending on
-    # the Python version. We wrap all our `__repr__` implementations with
-    # this and then use unicode throughout internally.
-    if six.PY2:
-        return value.encode('utf-8')
-    return value
-
-
 def unicode_http_header(value):
     # Coerce HTTP header value to unicode.
     if isinstance(value, bytes):
@@ -168,15 +136,6 @@ def is_guardian_installed():
     """
     django-guardian is optional and only imported if in INSTALLED_APPS.
     """
-    try:
-        import guardian
-    except ImportError:
-        guardian = None
-
-    if six.PY2 and (not guardian or guardian.VERSION >= (1, 5)):
-        # Guardian 1.5.0, for Django 2.2 is NOT compatible with Python 2.7.
-        # Remove when dropping PY2.
-        return False
     return 'guardian' in settings.INSTALLED_APPS
 
 
@@ -289,17 +248,12 @@ def md_filter_add_syntax_highlight(md):
 
 # `separators` argument to `json.dumps()` differs between 2.x and 3.x
 # See: https://bugs.python.org/issue22767
-if six.PY3:
-    SHORT_SEPARATORS = (',', ':')
-    LONG_SEPARATORS = (', ', ': ')
-    INDENT_SEPARATORS = (',', ': ')
-else:
-    SHORT_SEPARATORS = (b',', b':')
-    LONG_SEPARATORS = (b', ', b': ')
-    INDENT_SEPARATORS = (b',', b': ')
+SHORT_SEPARATORS = (',', ':')
+LONG_SEPARATORS = (', ', ': ')
+INDENT_SEPARATORS = (',', ': ')
 
 
-class CustomValidatorMessage(object):
+class CustomValidatorMessage:
     """
     We need to avoid evaluation of `lazy` translated `message` in `django.core.validators.BaseValidator.__init__`.
     https://github.com/django/django/blob/75ed5900321d170debef4ac452b8b3cf8a1c2384/django/core/validators.py#L297
@@ -309,7 +263,7 @@ class CustomValidatorMessage(object):
 
     def __init__(self, *args, **kwargs):
         self.message = kwargs.pop('message', self.message)
-        super(CustomValidatorMessage, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
 
 
 class MinValueValidator(CustomValidatorMessage, validators.MinValueValidator):

rest_framework/decorators.py

@@ -6,13 +6,10 @@
 based views, as well as the `@detail_route` and `@list_route` decorators, which are
 used to annotate methods on viewsets that should be included by routers.
 """
-from __future__ import unicode_literals
-
 import types
 import warnings
 
 from django.forms.utils import pretty_name
-from django.utils import six
 
 from rest_framework import RemovedInDRF310Warning
 from rest_framework.views import APIView
@@ -28,7 +25,7 @@ def api_view(http_method_names=None):
     def decorator(func):
 
         WrappedAPIView = type(
-            six.PY3 and 'WrappedAPIView' or b'WrappedAPIView',
+            'WrappedAPIView',
             (APIView,),
             {'__doc__': func.__doc__}
         )