Remove python2 compability code (#2033)

* remove sys.version_info == 2

* remove sys.version_info < 3

* remove from __future__ imports

Author: pmeier

references/classification/train.py

@@ -1,8 +1,6 @@
-from __future__ import print_function
 import datetime
 import os
 import time
-import sys
 
 import torch
 import torch.utils.data
@@ -141,12 +139,9 @@ def load_data(traindir, valdir, cache_dataset, distributed):
 
 
 def main(args):
-    if args.apex:
-        if sys.version_info < (3, 0):
-            raise RuntimeError("Apex currently only supports Python 3. Aborting.")
-        if amp is None:
-            raise RuntimeError("Failed to import apex. Please install apex from https://www.github.com/nvidia/apex "
-                               "to enable mixed-precision training.")
+    if args.apex and amp is None:
+        raise RuntimeError("Failed to import apex. Please install apex from https://www.github.com/nvidia/apex "
+                           "to enable mixed-precision training.")
 
     if args.output_dir:
         utils.mkdir(args.output_dir)

references/classification/train_quantization.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import datetime
 import os
 import time

references/classification/utils.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from collections import defaultdict, deque
 import datetime
 import time

references/detection/utils.py

@@ -1,5 +1,3 @@
-from __future__ import print_function
-
 from collections import defaultdict, deque
 import datetime
 import pickle

references/segmentation/utils.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from collections import defaultdict, deque
 import datetime
 import math

references/video_classification/train.py

@@ -1,9 +1,6 @@
-from __future__ import print_function
 import datetime
 import os
 import time
-import sys
-
 import torch
 import torch.utils.data
 from torch.utils.data.dataloader import default_collate
@@ -95,12 +92,9 @@ def collate_fn(batch):
 
 
 def main(args):
-    if args.apex:
-        if sys.version_info < (3, 0):
-            raise RuntimeError("Apex currently only supports Python 3. Aborting.")
-        if amp is None:
-            raise RuntimeError("Failed to import apex. Please install apex from https://www.github.com/nvidia/apex "
-                               "to enable mixed-precision training.")
+    if args.apex and amp is None:
+        raise RuntimeError("Failed to import apex. Please install apex from https://www.github.com/nvidia/apex "
+                           "to enable mixed-precision training.")
 
     if args.output_dir:
         utils.mkdir(args.output_dir)

references/video_classification/utils.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from collections import defaultdict, deque
 import datetime
 import time

setup.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import os
 import io
 import re

test/fakedata_generation.py

@@ -1,18 +1,12 @@
 import os
-import sys
 import contextlib
 import tarfile
 import json
 import numpy as np
 import PIL
 import torch
 from common_utils import get_tmp_dir
-
-PYTHON2 = sys.version_info[0] == 2
-if PYTHON2:
-    import cPickle as pickle
-else:
-    import pickle
+import pickle
 
 
 @contextlib.contextmanager

test/test_functional_tensor.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 from torch import Tensor
 import torchvision.transforms as transforms

test/test_ops.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import math
 import unittest
 

test/test_transforms.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import os
 import mock
 import torch

test/test_transforms_video.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 import torchvision.transforms._transforms_video as transforms
 from torchvision.transforms import Compose

test/test_video_reader.py

@@ -1,7 +1,6 @@
 import collections
 import math
 import os
-import sys
 import time
 import unittest
 from fractions import Fraction
@@ -22,10 +21,7 @@
     av = None
 
 
-if sys.version_info < (3,):
-    from urllib2 import URLError
-else:
-    from urllib.error import URLError
+from urllib.error import URLError
 
 
 VIDEO_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "assets", "videos")

torchvision/datasets/caltech.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from PIL import Image
 import os
 import os.path

torchvision/datasets/cifar.py

@@ -1,14 +1,8 @@
-from __future__ import print_function
 from PIL import Image
 import os
 import os.path
 import numpy as np
-import sys
-
-if sys.version_info[0] == 2:
-    import cPickle as pickle
-else:
-    import pickle
+import pickle
 
 from .vision import VisionDataset
 from .utils import check_integrity, download_and_extract_archive
@@ -79,10 +73,7 @@ def __init__(self, root, train=True, transform=None, target_transform=None,
         for file_name, checksum in downloaded_list:
             file_path = os.path.join(self.root, self.base_folder, file_name)
             with open(file_path, 'rb') as f:
-                if sys.version_info[0] == 2:
-                    entry = pickle.load(f)
-                else:
-                    entry = pickle.load(f, encoding='latin1')
+                entry = pickle.load(f, encoding='latin1')
                 self.data.append(entry['data'])
                 if 'labels' in entry:
                     self.targets.extend(entry['labels'])
@@ -100,10 +91,7 @@ def _load_meta(self):
             raise RuntimeError('Dataset metadata file not found or corrupted.' +
                                ' You can use download=True to download it')
         with open(path, 'rb') as infile:
-            if sys.version_info[0] == 2:
-                data = pickle.load(infile)
-            else:
-                data = pickle.load(infile, encoding='latin1')
+            data = pickle.load(infile, encoding='latin1')
             self.classes = data[self.meta['key']]
         self.class_to_idx = {_class: i for i, _class in enumerate(self.classes)}
 

torchvision/datasets/lsun.py

@@ -11,11 +11,7 @@
 else:
     from collections.abc import Iterable
 
-if sys.version_info[0] == 2:
-    import cPickle as pickle
-else:
-    import pickle
-
+import pickle
 from .utils import verify_str_arg, iterable_to_str
 
 

torchvision/datasets/mnist.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from .vision import VisionDataset
 import warnings
 from PIL import Image

torchvision/datasets/omniglot.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from PIL import Image
 from os.path import join
 import os

torchvision/datasets/semeion.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from PIL import Image
 import os
 import os.path

torchvision/datasets/stl10.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from PIL import Image
 import os
 import os.path

torchvision/datasets/svhn.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from .vision import VisionDataset
 from PIL import Image
 import os

torchvision/datasets/usps.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 from PIL import Image
 import os
 import numpy as np

torchvision/datasets/voc.py

@@ -1,14 +1,8 @@
 import os
-import sys
 import tarfile
 import collections
 from .vision import VisionDataset
-
-if sys.version_info[0] == 2:
-    import xml.etree.cElementTree as ET
-else:
-    import xml.etree.ElementTree as ET
-
+import xml.etree.ElementTree as ET
 from PIL import Image
 from .utils import download_url, check_integrity, verify_str_arg
 

torchvision/models/detection/_utils.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 import math
 
 import torch

torchvision/models/detection/image_list.py

@@ -1,6 +1,4 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
-from __future__ import division
-
 import torch
 from torch.jit.annotations import List, Tuple
 from torch import Tensor

torchvision/models/detection/roi_heads.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 import torchvision
 

torchvision/models/detection/rpn.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 import torch
 from torch.nn import functional as F

torchvision/models/detection/transform.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 import random
 import math
 import torch

torchvision/models/googlenet.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 import warnings
 from collections import namedtuple
 import torch

torchvision/models/inception.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 from collections import namedtuple
 import warnings
 import torch

torchvision/ops/boxes.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 import torch
 from torch.jit.annotations import Tuple
 from torch import Tensor

torchvision/ops/misc.py

@@ -1,4 +1,3 @@
-from __future__ import division
 from collections import OrderedDict
 from torch.jit.annotations import Optional, List
 from torch import Tensor

torchvision/ops/poolers.py

@@ -1,5 +1,3 @@
-from __future__ import division
-
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 import torch
 import torch.nn.functional as F

torchvision/transforms/functional.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 import sys
 import math

torchvision/transforms/functional_tensor.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 import torchvision.transforms.functional as F
 from torch import Tensor

torchvision/transforms/transforms.py

@@ -1,4 +1,3 @@
-from __future__ import division
 import torch
 import math
 import sys

travis-scripts/run-clang-format/run-clang-format.py

@@ -8,8 +8,6 @@
 
 """
 
-from __future__ import print_function, unicode_literals
-
 import argparse
 import codecs
 import difflib
@@ -129,19 +127,14 @@ def run_clang_format_diff(args, file):
     #   > Each translation completely replaces the format string
     #   > for the diagnostic.
     #   > -- http://clang.llvm.org/docs/InternalsManual.html#internals-diag-translation
-    #
-    # It's not pretty, due to Python 2 & 3 compatibility.
-    encoding_py3 = {}
-    if sys.version_info[0] >= 3:
-        encoding_py3['encoding'] = 'utf-8'
 
     try:
         proc = subprocess.Popen(
             invocation,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
             universal_newlines=True,
-            **encoding_py3)
+            encoding='utf-8')
     except OSError as exc:
         raise DiffError(
             "Command '{}' failed to start: {}".format(
@@ -150,12 +143,7 @@ def run_clang_format_diff(args, file):
         )
     proc_stdout = proc.stdout
     proc_stderr = proc.stderr
-    if sys.version_info[0] < 3:
-        # make the pipes compatible with Python 3,
-        # reading lines should output unicode
-        encoding = 'utf-8'
-        proc_stdout = codecs.getreader(encoding)(proc_stdout)
-        proc_stderr = codecs.getreader(encoding)(proc_stderr)
+
     # hopefully the stderr pipe won't get full and block the process
     outs = list(proc_stdout.readlines())
     errs = list(proc_stderr.readlines())
@@ -203,10 +191,7 @@ def red(s):
 def print_diff(diff_lines, use_color):
     if use_color:
         diff_lines = colorize(diff_lines)
-    if sys.version_info[0] < 3:
-        sys.stdout.writelines((l.encode('utf-8') for l in diff_lines))
-    else:
-        sys.stdout.writelines(diff_lines)
+    sys.stdout.writelines(diff_lines)
 
 
 def print_trouble(prog, message, use_colors):