POC: Lower min version of six

This change should allow installation of virtualenv on systems
with older six where their LTS support may prevent them from
upgrading it.

setup.cfg

@@ -43,7 +43,7 @@ install_requires =
     appdirs>=1.4.3,<2
     distlib>=0.3.0,<1
     filelock>=3.0.0,<4
-    six>=1.12.0,<2
+    six>=1.9.0,<2   # keep it >=1.9.0 as it may cause problems on LTS platforms
     contextlib2>=0.6.0,<1;python_version<"3.3"
     importlib-metadata>=0.12,<2;python_version<"3.8"
     importlib-resources>=1.0,<2;python_version<"3.7"

src/virtualenv/__main__.py

@@ -5,7 +5,7 @@
 import sys
 from datetime import datetime
 
-import six
+from virtualenv import _six as six
 
 
 def run(args=None, options=None):

src/virtualenv/_six.py

@@ -0,0 +1,48 @@
+"""Backward compatibility layer with older version of six.
+
+This is used to avoid virtualenv requring a version of six newer than what
+the system may have.
+"""
+from six import PY2, PY3, add_metaclass, binary_type, exec_, string_types, text_type  # noqa
+
+try:
+    from six import ensure_text
+except ImportError:
+
+    def ensure_text(s, encoding="utf-8", errors="strict"):
+        """Coerce *s* to six.text_type.
+        For Python 2:
+        - `unicode` -> `unicode`
+        - `str` -> `unicode`
+        For Python 3:
+        - `str` -> `str`
+        - `bytes` -> decoded to `str`
+        """
+        if isinstance(s, binary_type):
+            return s.decode(encoding, errors)
+        elif isinstance(s, text_type):
+            return s
+        else:
+            raise TypeError("not expecting type '%s'" % type(s))
+
+
+try:
+    from six import ensure_str
+except ImportError:
+
+    def ensure_str(s, encoding="utf-8", errors="strict"):
+        """Coerce *s* to `str`.
+        For Python 2:
+        - `unicode` -> encoded to `str`
+        - `str` -> `str`
+        For Python 3:
+        - `str` -> `str`
+        - `bytes` -> decoded to `str`
+        """
+        if not isinstance(s, (text_type, binary_type)):
+            raise TypeError("not expecting type '%s'" % type(s))
+        if PY2 and isinstance(s, text_type):
+            s = s.encode(encoding, errors)
+        elif PY3 and isinstance(s, binary_type):
+            s = s.decode(encoding, errors)
+        return s

src/virtualenv/activation/activator.py

@@ -2,7 +2,7 @@
 
 from abc import ABCMeta, abstractmethod
 
-import six
+import virtualenv._six as six
 
 
 @six.add_metaclass(ABCMeta)

src/virtualenv/activation/python/__init__.py

@@ -3,8 +3,7 @@
 import os
 from collections import OrderedDict
 
-import six
-
+import virtualenv._six as six
 from virtualenv.info import WIN_CPYTHON_2
 from virtualenv.util.path import Path
 

src/virtualenv/activation/via_template.py

@@ -4,7 +4,7 @@
 import sys
 from abc import ABCMeta, abstractmethod
 
-import six
+import virtualenv._six as six
 
 from .activator import Activator
 

src/virtualenv/config/env_var.py

@@ -2,7 +2,7 @@
 
 import os
 
-import six
+import virtualenv._six as six
 
 from .convert import convert
 

src/virtualenv/config/ini.py

@@ -3,8 +3,7 @@
 import logging
 import os
 
-import six
-
+import virtualenv._six as six
 from virtualenv.dirs import default_config_dir
 from virtualenv.info import PY3
 from virtualenv.util import ConfigParser

src/virtualenv/create/creator.py

@@ -11,9 +11,7 @@
 from collections import OrderedDict
 from stat import S_IWUSR
 
-import six
-from six import add_metaclass
-
+import virtualenv._six as six
 from virtualenv.discovery.cached_py_info import LogCmd
 from virtualenv.info import WIN_CPYTHON_2
 from virtualenv.pyenv_cfg import PyEnvCfg
@@ -26,7 +24,7 @@
 DEBUG_SCRIPT = HERE / "debug.py"
 
 
-@add_metaclass(ABCMeta)
+@six.add_metaclass(ABCMeta)
 class Creator(object):
     """A class that given a python Interpreter creates a virtual environment"""
 

src/virtualenv/create/describe.py

@@ -3,8 +3,7 @@
 from abc import ABCMeta
 from collections import OrderedDict
 
-from six import add_metaclass, ensure_text
-
+from virtualenv._six import add_metaclass, ensure_text
 from virtualenv.info import IS_WIN
 from virtualenv.util.path import Path
 

src/virtualenv/create/via_global_ref/api.py

@@ -2,7 +2,7 @@
 
 from abc import ABCMeta
 
-from six import add_metaclass
+from virtualenv._six import add_metaclass
 
 from ..creator import Creator
 

src/virtualenv/create/via_global_ref/builtin/builtin_way.py

@@ -2,8 +2,7 @@
 
 from abc import ABCMeta
 
-from six import add_metaclass
-
+from virtualenv._six import add_metaclass
 from virtualenv.create.creator import Creator
 from virtualenv.create.describe import Describe
 

src/virtualenv/create/via_global_ref/builtin/cpython/common.py

@@ -3,8 +3,7 @@
 from abc import ABCMeta
 from collections import OrderedDict
 
-from six import add_metaclass
-
+from virtualenv._six import add_metaclass
 from virtualenv.create.describe import PosixSupports, WindowsSupports
 from virtualenv.util.path import Path
 

src/virtualenv/create/via_global_ref/builtin/cpython/cpython2.py

@@ -3,8 +3,7 @@
 import abc
 import logging
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.util.path import Path
 

src/virtualenv/create/via_global_ref/builtin/cpython/cpython3.py

@@ -2,8 +2,7 @@
 
 import abc
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.describe import Python3Supports
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.util.path import Path

src/virtualenv/create/via_global_ref/builtin/pypy/common.py

@@ -2,8 +2,7 @@
 
 import abc
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.util.path import Path
 

src/virtualenv/create/via_global_ref/builtin/pypy/pypy2.py

@@ -3,8 +3,7 @@
 import abc
 import logging
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.describe import PosixSupports, WindowsSupports
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.util.path import Path

src/virtualenv/create/via_global_ref/builtin/pypy/pypy3.py

@@ -2,8 +2,7 @@
 
 import abc
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.describe import PosixSupports, Python3Supports, WindowsSupports
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.util.path import Path

src/virtualenv/create/via_global_ref/builtin/python2/python2.py

@@ -4,8 +4,7 @@
 import json
 import os
 
-import six
-
+import virtualenv._six as six
 from virtualenv.create.describe import Python2Supports
 from virtualenv.create.via_global_ref.builtin.ref import PathRefToDest
 from virtualenv.info import IS_ZIPAPP

src/virtualenv/create/via_global_ref/builtin/ref.py

@@ -5,8 +5,7 @@
 from collections import OrderedDict
 from stat import S_IXGRP, S_IXOTH, S_IXUSR
 
-from six import add_metaclass, ensure_text
-
+from virtualenv._six import add_metaclass, ensure_text
 from virtualenv.info import PY3, fs_is_case_sensitive, fs_supports_symlink
 from virtualenv.util.path import copy, link, make_exe, symlink
 

src/virtualenv/create/via_global_ref/builtin/via_global_self_do.py

@@ -4,8 +4,7 @@
 from abc import ABCMeta
 from collections import namedtuple
 
-from six import add_metaclass
-
+from virtualenv._six import add_metaclass
 from virtualenv.create.via_global_ref.builtin.ref import ExePathRefToDest
 from virtualenv.info import fs_supports_symlink
 from virtualenv.util.path import ensure_dir

src/virtualenv/discovery/builtin.py

@@ -4,8 +4,7 @@
 import os
 import sys
 
-import six
-
+import virtualenv._six as six
 from virtualenv.info import IS_WIN
 
 from .discover import Discover

src/virtualenv/discovery/cached_py_info.py

@@ -14,8 +14,7 @@
 from collections import OrderedDict
 from hashlib import sha256
 
-from six import ensure_text
-
+from virtualenv._six import ensure_text
 from virtualenv.dirs import default_data_dir
 from virtualenv.discovery.py_info import PythonInfo
 from virtualenv.info import PY2, PY3

src/virtualenv/discovery/discover.py

@@ -2,7 +2,7 @@
 
 from abc import ABCMeta, abstractmethod
 
-import six
+import virtualenv._six as six
 
 
 @six.add_metaclass(ABCMeta)

src/virtualenv/discovery/py_spec.py

@@ -6,8 +6,7 @@
 import sys
 from collections import OrderedDict
 
-import six
-
+import virtualenv._six as six
 from virtualenv.info import fs_is_case_sensitive
 
 PATTERN = re.compile(r"^(?P<impl>[a-zA-Z]+)?(?P<version>[0-9.]+)?(?:-(?P<arch>32|64))?$")

src/virtualenv/discovery/windows/pep514.py

@@ -5,7 +5,7 @@
 import re
 from logging import basicConfig, getLogger
 
-import six
+import virtualenv._six as six
 
 if six.PY3:
     import winreg

src/virtualenv/pyenv_cfg.py

@@ -3,7 +3,7 @@
 import logging
 from collections import OrderedDict
 
-import six
+import virtualenv._six as six
 
 
 class PyEnvCfg(object):

src/virtualenv/report.py

@@ -3,7 +3,7 @@
 import logging
 import sys
 
-import six
+import virtualenv._six as six
 
 LEVELS = {
     0: logging.CRITICAL,

src/virtualenv/seed/embed/base_embed.py

@@ -2,8 +2,7 @@
 
 from abc import ABCMeta
 
-import six
-
+import virtualenv._six as six
 from virtualenv.util.path import Path
 
 from ..seeder import Seeder

src/virtualenv/seed/embed/wheels/acquire.py

@@ -10,8 +10,7 @@
 from shutil import copy2
 from zipfile import ZipFile
 
-import six
-
+import virtualenv._six as six
 from virtualenv.info import IS_ZIPAPP
 from virtualenv.util.path import Path
 from virtualenv.util.subprocess import Popen, subprocess

src/virtualenv/seed/seeder.py

@@ -2,7 +2,7 @@
 
 from abc import ABCMeta, abstractmethod
 
-import six
+import virtualenv._six as six
 
 
 @six.add_metaclass(ABCMeta)

src/virtualenv/seed/via_app_data/pip_install/base.py

@@ -8,9 +8,8 @@
 from abc import ABCMeta, abstractmethod
 from tempfile import mkdtemp
 
-import six
-from six import PY3
-
+import virtualenv._six as six
+from virtualenv._six import PY3
 from virtualenv.util import ConfigParser
 from virtualenv.util.path import Path
 

src/virtualenv/seed/via_app_data/pip_install/copy.py

@@ -2,8 +2,7 @@
 
 import os
 
-import six
-
+import virtualenv._six as six
 from virtualenv.util.path import Path, copy
 
 from .base import PipInstall

src/virtualenv/seed/via_app_data/pip_install/symlink.py

@@ -5,8 +5,7 @@
 import subprocess
 from stat import S_IREAD, S_IRGRP, S_IROTH, S_IWUSR
 
-import six
-
+import virtualenv._six as six
 from virtualenv.util.subprocess import Popen
 
 from .base import PipInstall

src/virtualenv/seed/via_app_data/via_app_data.py

@@ -6,8 +6,7 @@
 from contextlib import contextmanager
 from threading import Lock, Thread
 
-import six
-
+import virtualenv._six as six
 from virtualenv.dirs import default_data_dir
 from virtualenv.info import fs_supports_symlink
 from virtualenv.seed.embed.base_embed import BaseEmbed

src/virtualenv/session.py

@@ -3,7 +3,7 @@
 import json
 import logging
 
-import six
+import virtualenv._six as six
 
 
 class Session(object):