Remove six dependency (#2017)

* remove six from python code

* remove six from setup.py

* remove six from tests

* remove six from references

* remove six from packaging

* revert str to torch._six._string_classes

* revert str to torch._six._string_classes

packaging/torchvision/meta.yaml

@@ -20,7 +20,6 @@ requirements:
     - python
     - pillow >=4.1.1
     - numpy >=1.11
-    - six
     {{ environ.get('CONDA_PYTORCH_CONSTRAINT') }}
     {{ environ.get('CONDA_CUDATOOLKIT_CONSTRAINT') }}
 

setup.py

@@ -69,7 +69,6 @@ if os.getenv('PYTORCH_VERSION'):
 
 requirements = [
     'numpy',
-    'six',
     pytorch_dep,
 ]
 

test/common_utils.py

@@ -11,7 +11,7 @@ import errno
 import __main__
 
 from numbers import Number
-from torch._six import string_classes, inf
+from torch._six import string_classes
 from collections import OrderedDict
 
 
@@ -255,6 +255,7 @@ class TestCase(unittest.TestCase):
         elif isinstance(x, bool) and isinstance(y, bool):
             super(TestCase, self).assertEqual(x, y, message)
         elif isinstance(x, Number) and isinstance(y, Number):
+            inf = float("inf")
             if abs(x) == inf or abs(y) == inf:
                 if allow_inf:
                     super(TestCase, self).assertEqual(x, y, message)

test/test_datasets_utils.py

@@ -7,7 +7,6 @@ import zipfile
 import tarfile
 import gzip
 import warnings
-from torch._six import PY2
 from torch._utils_internal import get_file_path_2
 
 from common_utils import get_tmp_dir
@@ -41,7 +40,6 @@ class Tester(unittest.TestCase):
         self.assertTrue(utils.check_integrity(existing_fpath))
         self.assertFalse(utils.check_integrity(nonexisting_fpath))
 
-    @unittest.skipIf(PY2, "https://github.com/pytorch/vision/issues/1268")
     def test_download_url(self):
         with get_tmp_dir() as temp_dir:
             url = "http://github.com/pytorch/vision/archive/master.zip"
@@ -53,7 +51,6 @@ class Tester(unittest.TestCase):
                 warnings.warn(msg, RuntimeWarning)
                 raise unittest.SkipTest(msg)
 
-    @unittest.skipIf(PY2, "https://github.com/pytorch/vision/issues/1268")
     def test_download_url_retry_http(self):
         with get_tmp_dir() as temp_dir:
             url = "https://github.com/pytorch/vision/archive/master.zip"

torchvision/datasets/flickr.py

 from collections import defaultdict
 from PIL import Image
-from six.moves import html_parser
+from html.parser import HTMLParser
 
 import glob
 import os
 from .vision import VisionDataset
 
 
-class Flickr8kParser(html_parser.HTMLParser):
+class Flickr8kParser(HTMLParser):
     """Parser for extracting captions from the Flickr8k dataset web page."""
 
     def __init__(self, root):

torchvision/datasets/lsun.py

@@ -2,7 +2,7 @@ from .vision import VisionDataset
 from PIL import Image
 import os
 import os.path
-import six
+import io
 import string
 import sys
 
@@ -43,7 +43,7 @@ class LSUNClass(VisionDataset):
         with env.begin(write=False) as txn:
             imgbuf = txn.get(self.keys[index])
 
-        buf = six.BytesIO()
+        buf = io.BytesIO()
         buf.write(imgbuf)
         buf.seek(0)
         img = Image.open(buf).convert('RGB')

torchvision/datasets/sbu.py

 from PIL import Image
-from six.moves import zip
 from .utils import download_url, check_integrity
 
 import os

torchvision/datasets/utils.py

@@ -8,7 +8,6 @@ import zipfile
 
 import torch
 from torch.utils.model_zoo import tqdm
-from torch._six import PY3
 
 
 def gen_bar_updater():
@@ -52,7 +51,7 @@ def download_url(url, root, filename=None, md5=None):
         filename (str, optional): Name to save the file under. If None, use the basename of the URL
         md5 (str, optional): MD5 checksum of the download. If None, do not check
     """
-    from six.moves import urllib
+    import urllib
 
     root = os.path.expanduser(root)
     if not filename:
@@ -222,8 +221,7 @@ def extract_archive(from_path, to_path=None, remove_finished=False):
     elif _is_targz(from_path) or _is_tgz(from_path):
         with tarfile.open(from_path, 'r:gz') as tar:
             tar.extractall(path=to_path)
-    elif _is_tarxz(from_path) and PY3:
-        # .tar.xz archive only supported in Python 3.x
+    elif _is_tarxz(from_path):
         with tarfile.open(from_path, 'r:xz') as tar:
             tar.extractall(path=to_path)
     elif _is_gzip(from_path):