Replace all six.BytesIO with io.BytesIO

sphinx/environment/__init__.py

@@ -15,9 +15,10 @@ import sys
 import warnings
 from collections import defaultdict
 from copy import copy
+from io import BytesIO
 from os import path
 
-from six import BytesIO, next
+from six import next
 
 from sphinx import addnodes
 from sphinx.deprecation import RemovedInSphinx30Warning, RemovedInSphinx40Warning
@@ -747,7 +748,7 @@ class BuildEnvironment:
 
     @classmethod
     def loads(cls, string, app=None):
-        # type: (unicode, Sphinx) -> BuildEnvironment
+        # type: (bytes, Sphinx) -> BuildEnvironment
         warnings.warn('BuildEnvironment.loads() is deprecated. '
                       'Please use pickle.loads() instead.',
                       RemovedInSphinx30Warning)

sphinx/pycode/__init__.py

@@ -11,9 +11,10 @@
 from __future__ import print_function
 
 import re
+from io import BytesIO
 from zipfile import ZipFile
 
-from six import BytesIO, StringIO
+from six import StringIO
 
 from sphinx.errors import PycodeError
 from sphinx.pycode.parser import Parser

sphinx/util/images.py

@@ -14,11 +14,12 @@ import base64
 import imghdr
 import warnings
 from collections import OrderedDict
+from io import BytesIO
 from os import path
 from typing import NamedTuple
 
 import imagesize
-from six import BytesIO, text_type
+from six import text_type
 
 from sphinx.deprecation import RemovedInSphinx30Warning
 

tests/test_search.py

@@ -9,12 +9,12 @@
     :license: BSD, see LICENSE for details.
 """
 
+from io import BytesIO
 from collections import namedtuple
 
 import pytest
 from docutils import frontend, utils
 from docutils.parsers import rst
-from six import BytesIO
 
 from sphinx.search import IndexBuilder
 from sphinx.util import jsdump

tests/test_util_inventory.py

@@ -11,8 +11,7 @@
 
 import posixpath
 import zlib
-
+from io import BytesIO
-from six import BytesIO
 
 from sphinx.ext.intersphinx import InventoryFile