remove some dead code especially wrt py3compat

IPython/core/completer.py

@@ -178,14 +178,6 b' else:'
 MATCHES_LIMIT = 500
 
 
-class Sentinel:
-    def __repr__(self):
-        return "<deprecated sentinel>"
-
-
-_deprecation_readline_sentinel = Sentinel()
-
-
 class ProvisionalCompleterWarning(FutureWarning):
     """
     Exception raise by an experimental feature in this module.
@@ -618,8 +610,6 b' class Completer(Configurable):'
              "Includes completion of latex commands, unicode names, and expanding "
              "unicode characters back to latex commands.").tag(config=True)
 
-
-
     def __init__(self, namespace=None, global_namespace=None, **kwargs):
         """Create a new completer for the command line.
 
@@ -1119,8 +1109,9 b' class IPCompleter(Completer):'
             'no effects and then removed in future version of IPython.',
             UserWarning)
 
-    def __init__(self, shell=None, namespace=None, global_namespace=None,
-                 use_readline=_deprecation_readline_sentinel, config=None, **kwargs):
+    def __init__(
+        self, shell=None, namespace=None, global_namespace=None, config=None, **kwargs
+    ):
         """IPCompleter() -> completer
 
         Return a completer object.
@@ -1144,10 +1135,6 b' class IPCompleter(Completer):'
         self.magic_escape = ESC_MAGIC
         self.splitter = CompletionSplitter()
 
-        if use_readline is not _deprecation_readline_sentinel:
-            warnings.warn('The `use_readline` parameter is deprecated and ignored since IPython 6.0.',
-                          DeprecationWarning, stacklevel=2)
-
         # _greedy_changed() depends on splitter and readline being defined:
         Completer.__init__(self, namespace=namespace, global_namespace=global_namespace,
                             config=config, **kwargs)

IPython/core/tests/test_iplib.py

@@ -133,7 +133,7 b' def doctest_tb_sysexit():'
     In [20]: %tb
     Traceback (most recent call last):
       File ..., in execfile
-        exec(compiler(f.read(), fname, 'exec'), glob, loc)
+        exec(compiler(f.read(), fname, "exec"), glob, loc)
       File ..., in <module>
         bar(mode)
       File ..., in bar
@@ -149,9 +149,9 b' def doctest_tb_sysexit():'
     ---------------------------------------------------------------------------
     SystemExit                                Traceback (most recent call last)
     File ..., in execfile(fname, glob, loc, compiler)
-         70 with open(fname, 'rb') as f:
-         71     compiler = compiler or compile
-    ---> 72     exec(compiler(f.read(), fname, 'exec'), glob, loc)
+         ... with open(fname, "rb") as f:
+         ...     compiler = compiler or compile
+    ---> ...     exec(compiler(f.read(), fname, "exec"), glob, loc)
     ...<module>
          30     except IndexError:
          31         mode = 'div'

IPython/utils/_process_cli.py

@@ -19,7 +19,6 b' import System'
 import os
 
 # Import IPython libraries:
-from IPython.utils import py3compat
 from ._process_common import arg_split
 
 

IPython/utils/_process_posix.py

@@ -24,7 +24,6 b' import pexpect'
 
 # Our own
 from ._process_common import getoutput, arg_split
-from IPython.utils import py3compat
 from IPython.utils.encoding import DEFAULT_ENCODING
 
 #-----------------------------------------------------------------------------

IPython/utils/py3compat.py

@@ -3,13 +3,8 b''
 
 This file is deprecated and will be removed in a future version.
 """
-import functools
-import os
-import sys
-import re
-import shutil
-import types
 import platform
+import builtins as builtin_mod
 
 from .encoding import DEFAULT_ENCODING
 
@@ -18,6 +13,7 b' def decode(s, encoding=None):'
     encoding = encoding or DEFAULT_ENCODING
     return s.decode(encoding, "replace")
 
+
 def encode(u, encoding=None):
     encoding = encoding or DEFAULT_ENCODING
     return u.encode(encoding, "replace")
@@ -28,16 +24,6 b' def cast_unicode(s, encoding=None):'
         return decode(s, encoding)
     return s
 
-def cast_bytes(s, encoding=None):
-    if not isinstance(s, bytes):
-        return encode(s, encoding)
-    return s
-
-def buffer_to_bytes(buf):
-    """Cast a buffer object to bytes"""
-    if not isinstance(buf, bytes):
-        buf = bytes(buf)
-    return buf
 
 def safe_unicode(e):
     """unicode(e) with various fallbacks. Used for exceptions, which may not be
@@ -53,23 +39,21 b' def safe_unicode(e):'
     except UnicodeError:
         pass
 
-    return u'Unrecoverably corrupt evalue'
+    return "Unrecoverably corrupt evalue"
+
 
 # keep reference to builtin_mod because the kernel overrides that value
 # to forward requests to a frontend.
-def input(prompt=''):
+def input(prompt=""):
     return builtin_mod.input(prompt)
 
-builtin_mod_name = "builtins"
-import builtins as builtin_mod
-
-MethodType = types.MethodType
 
 def execfile(fname, glob, loc=None, compiler=None):
     loc = loc if (loc is not None) else glob
-    with open(fname, 'rb') as f:
+    with open(fname, "rb") as f:
         compiler = compiler or compile
-        exec(compiler(f.read(), fname, 'exec'), glob, loc)
+        exec(compiler(f.read(), fname, "exec"), glob, loc)
+
 
 PYPY = platform.python_implementation() == "PyPy"
 
@@ -77,6 +61,7 b' PYPY = platform.python_implementation() == "PyPy"'
 # See https://github.com/cython/cython/pull/3291 and
 # https://github.com/ipython/ipython/issues/12068
 def no_code(x, encoding=None):
-        return x
-unicode_to_str = cast_bytes_py2 = no_code
+    return x
 
+
+unicode_to_str = cast_bytes_py2 = no_code