Delete Python <= 3.5 specific checks from the code (pytorch#39879)

Summary:
Remove PY3 and PY34 checks from `torch/testing/_internal/common_utils.py`
 Remove PY35 global var from `torch.jit.annotations`
Always call `try_get_real_signature` in `torch/jit/annotations.py`
Use `map` instead of `imap`, since Python-2 is no longer support, so map is always lazy.
Remove all pre Python-3.6 checks from `torch/_six.py` and `torch/_appdirs.py`
Pull Request resolved: pytorch#39879

Differential Revision: D22037811

Pulled By: malfet

fbshipit-source-id: af0c79f976569c2059d39ecb49c6b8285161734f

test/test_jit.py

@@ -4378,6 +4378,7 @@ def test_is_optional(self):
         torch._jit_internal.is_optional(ann)
 
     def test_interpreter_fuzz(self):
+        import builtins
         # This test generates random tree-like programs to fuzz test
         # that the interpreter does not have a bug in its stack manipulation
         # code. An assert in that code ensures individual operators are
@@ -4427,7 +4428,7 @@ def select_expr_or_var():
         for i in range(100):
             g = {'torch': torch}
             code = gen_code()
-            torch._six.exec_(code, g, None)
+            builtins.exec(code, g, None)
             cu = torch.jit.CompilationUnit(code)
             with freeze_rng_state():
                 o1 = g['f']()

torch/_appdirs.py

@@ -53,10 +53,7 @@
 import sys
 import os
 
-PY3 = sys.version_info[0] == 3
-
-if PY3:
-    unicode = str
+unicode = str
 
 if sys.platform.startswith('java'):
     import platform
@@ -498,10 +495,7 @@ def _get_win_folder_from_registry(csidl_name):
     registry for this guarantees us the correct answer for all CSIDL_*
     names.
     """
-    if PY3:
-      import winreg as _winreg
-    else:
-      import _winreg
+    import winreg as _winreg
 
     shell_folder_name = {
         "CSIDL_APPDATA": "AppData",

torch/_six.py

@@ -18,55 +18,24 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-import itertools
+import builtins
+import collections.abc
+import io
+import math
 import sys
 import types
-import inspect
-
-
-PY2 = sys.version_info[0] == 2
+import queue  # noqa: F401
+
+inf = math.inf
+nan = math.nan
+string_classes = (str, bytes)
+int_classes = int
+FileNotFoundError = builtins.FileNotFoundError
+StringIO = io.StringIO
+container_abcs = collections.abc
 PY3 = sys.version_info[0] == 3
 PY37 = sys.version_info[0] == 3 and sys.version_info[1] == 7
 
-
-if PY2:
-    import __builtin__ as builtins
-elif PY3:
-    import builtins
-
-
-if PY2:
-    inf = float('inf')
-    nan = float('nan')
-else:
-    import math
-    inf = math.inf
-    nan = math.nan
-
-if PY2:
-    string_classes = basestring
-else:
-    string_classes = (str, bytes)
-
-
-if PY2:
-    int_classes = (int, long)
-else:
-    int_classes = int
-
-
-if PY2:
-    FileNotFoundError = IOError
-else:
-    FileNotFoundError = builtins.FileNotFoundError
-
-
-if PY2:
-    import Queue as queue  # noqa: F401
-else:
-    import queue  # noqa: F401
-
-
 def with_metaclass(meta, *bases):
     """Create a base class with a metaclass."""
     # This requires a bit of explanation: the basic idea is to make a dummy
@@ -79,74 +48,16 @@ def __new__(cls, name, this_bases, d):
     return type.__new__(metaclass, 'temporary_class', (), {})
 
 
-# A portable way of referring to the generator version of map
-# in both Python 2 and Python 3.
-if hasattr(itertools, 'imap'):
-    imap = itertools.imap  # type: ignore
-else:
-    imap = map  # type: ignore
-
-
-if PY3:
-    import builtins
-    # See https://github.com/PyCQA/flake8-bugbear/issues/64
-    exec_ = getattr(builtins, "exec")  # noqa: B009
-else:
-    def exec_(_code_, _globs_=None, _locs_=None):
-        """Execute code in a namespace."""
-        if _globs_ is None:
-            frame = sys._getframe(1)
-            _globs_ = frame.f_globals
-            if _locs_ is None:
-                _locs_ = frame.f_locals
-            del frame
-        elif _locs_ is None:
-            _locs_ = _globs_
-        exec("""exec _code_ in _globs_, _locs_""")
-
-
-if sys.version_info[:2] == (3, 2):
-    exec_("""def raise_from(value, from_value):
+def raise_from(value, from_value):
     try:
-        if from_value is None:
-            raise value
         raise value from from_value
     finally:
         value = None
-""")
-elif sys.version_info[:2] > (3, 2):
-    exec_("""def raise_from(value, from_value):
-    try:
-        raise value from from_value
-    finally:
-        value = None
-""")
-else:
-    def raise_from(value, from_value):
-        raise value
 
-if PY2:
-    import collections
-    container_abcs = collections
-elif PY3:
-    import collections.abc
-    container_abcs = collections.abc
 
 # Gets a function from the name of a method on a type
-if PY2:
-    def get_function_from_type(cls, name):
-        method = getattr(cls, name, None)
-        return getattr(method, "__func__", None)
-elif PY3:
-    def get_function_from_type(cls, name):
-        return getattr(cls, name, None)
-
-if PY2:
-    import StringIO
-    StringIO = StringIO.StringIO
-elif PY3:
-    import io
-    StringIO = io.StringIO
+def get_function_from_type(cls, name):
+    return getattr(cls, name, None)
 
 
 # The codes below is not copied from the six package, so the copyright
@@ -164,9 +75,4 @@ def istuple(obj):
     return isinstance(obj, tuple) or t.__module__ == 'torch.return_types'
 
 def bind_method(fn, obj, obj_type):
-    if PY2:
-        if inspect.ismethod(fn):
-            fn = fn.__func__
-        return types.MethodType(fn, obj, obj_type)
-    else:
-        return types.MethodType(fn, obj)
+    return types.MethodType(fn, obj)

torch/jit/annotations.py

@@ -1,4 +1,3 @@
-import sys
 import ast
 import inspect
 import re
@@ -17,9 +16,6 @@
 from typing import Callable
 
 
-PY35 = sys.version_info >= (3, 5)
-
-
 class Module(object):
     def __init__(self, name, members):
         self.name = name
@@ -56,18 +52,15 @@ def __getitem__(self, name):
         return getattr(builtins, name, None)
 
 def get_signature(fn, rcb, loc, is_method):
-    # Python 3.5 adds support for the nice annotation syntax, so try that first.
-    signature = None
-    if PY35:
-        signature = try_real_annotations(fn, loc)
-        if signature is not None and is_method:
-            # If this is a method, then the signaure will include a type for
-            # `self`, but type comments do not contain a `self`. So strip it
-            # away here so everything is consistent (`inspect.ismethod` does
-            # not work here since `fn` is unbound at this point)
-            param_types, return_type = signature
-            param_types = param_types[1:]
-            signature = (param_types, return_type)
+    signature = try_real_annotations(fn, loc)
+    if signature is not None and is_method:
+        # If this is a method, then the signature will include a type for
+        # `self`, but type comments do not contain a `self`. So strip it
+        # away here so everything is consistent (`inspect.ismethod` does
+        # not work here since `fn` is unbound at this point)
+        param_types, return_type = signature
+        param_types = param_types[1:]
+        signature = (param_types, return_type)
 
     if signature is None:
         type_line, source = None, None

torch/tensor.py

@@ -6,7 +6,6 @@
 import torch.utils.hooks as hooks
 import warnings
 import weakref
-from torch._six import imap
 from torch._C import _add_docstr
 from numbers import Number
 import functools
@@ -445,20 +444,14 @@ def __len__(self):
         return self.shape[0]
 
     def __iter__(self):
-        # NB: we use 'imap' and not 'map' here, so that in Python 2 we get a
-        # generator and don't eagerly perform all the indexes.  This could
-        # save us work, and also helps keep trace ordering deterministic
-        # (e.g., if you zip(*hiddens), the eager map will force all the
-        # indexes of hiddens[0] before hiddens[1], while the generator
-        # map will interleave them.)
         if self.dim() == 0:
             raise TypeError('iteration over a 0-d tensor')
         if torch._C._get_tracing_state():
             warnings.warn('Iterating over a tensor might cause the trace to be incorrect. '
                           'Passing a tensor of different shape won\'t change the number of '
                           'iterations executed (and might lead to errors or silently give '
                           'incorrect results).', category=RuntimeWarning)
-        return iter(imap(lambda i: self[i], range(self.size(0))))
+        return iter(map(lambda i: self[i], range(self.size(0))))
 
     def __hash__(self):
         return id(self)

torch/testing/_internal/common_utils.py

@@ -212,10 +212,7 @@ def repeat_helper(f):
         @wraps(f)
         def call_helper(self, *args):
             for dtype in dtypes:
-                if PY34:
-                    with TestCase.subTest(self, dtype=dtype):
-                        f(self, *args, dtype=dtype)
-                else:
+                with TestCase.subTest(self, dtype=dtype):
                     f(self, *args, dtype=dtype)
 
         return call_helper
@@ -224,8 +221,6 @@ def call_helper(self, *args):
 # Environment variable `IS_PYTORCH_CI` is set in `.jenkins/common.sh`.
 IS_PYTORCH_CI = bool(os.environ.get('IS_PYTORCH_CI'))
 
-PY3 = sys.version_info > (3, 0)
-PY34 = sys.version_info >= (3, 4)
 
 def discover_test_cases_recursively(suite_or_case):
     if isinstance(suite_or_case, unittest.TestCase):
@@ -242,7 +237,6 @@ def chunk_list(lst, nchunks):
     return [lst[i::nchunks] for i in range(nchunks)]
 
 
-
 def run_tests(argv=UNITTEST_ARGS):
     if TEST_DISCOVER:
         suite = unittest.TestLoader().loadTestsFromModule(__main__)
@@ -319,15 +313,10 @@ def _check_module_exists(name):
     our tests, e.g., setting multiprocessing start method when imported
     (see librosa/#747, torchvision/#544).
     """
-    if not PY34:  # Python [3, 3.4)
-        import importlib
-        loader = importlib.find_loader(name)
-        return loader is not None
-    else:  # Python >= 3.4
-        import importlib
-        import importlib.util
-        spec = importlib.util.find_spec(name)
-        return spec is not None
+    import importlib
+    import importlib.util
+    spec = importlib.util.find_spec(name)
+    return spec is not None
 
 TEST_NUMPY = _check_module_exists('numpy')
 TEST_SCIPY = _check_module_exists('scipy')