Remove support for Python 2

Python 2.7 (the last Python 2 release) was End-Of-Life on 1-Jan-2020.

  * Add requirement to `setup.py` for python_requires=">=3.4.0"
  * Remove all usage of the `six` library
  * Remove declared support for Python 2
  * Update tox.ini to remove `py27` environment
  * Update Github workflows to no longer test against Python 2.7
  * Remove `from __future__ import print_function`
  * Remove `from __future__ unicode_literals`
  * Update tests to import `unittest` and `unittest.mock` directly

Closes: mjs#401

.github/workflows/main.yml

@@ -15,14 +15,12 @@ jobs:
       fail-fast: false
       matrix:
         python-version:
-          - "2.7"
           - "3.4"
           - "3.5"
           - "3.6"
           - "3.7"
           - "3.8"
           - "3.9"
-          - "pypy2"
           - "pypy3"
     steps:
     - uses: actions/checkout@v2

README.rst

@@ -5,7 +5,7 @@ library.
 
 =========================  ========================================
 Current version            2.2.0
-Supported Python versions  2.7, 3.4 - 3.9
+Supported Python versions  3.4 - 3.9
 License                    New BSD
 Project home               https://github.com/mjs/imapclient/
 PyPI                       https://pypi.python.org/pypi/IMAPClient

doc/src/concepts.rst

@@ -102,13 +102,6 @@ When constructing a custom context it is usually best to start with
 the default context, created by the ``ssl`` module, and modify it to
 suit your needs.
 
-.. warning::
-
-  Users of Python 2.7.0 - 2.7.8 can use TLS but cannot configure
-  the settings via an ``ssl.SSLContext``. These Python versions are
-  also not capable of proper certification verification. It is highly
-  encouraged to upgrade to a more recent version of Python.
-
 The following example shows how to to disable certification
 verification and certificate host name checks if required.
 

doc/src/index.rst

@@ -30,7 +30,7 @@ explains IMAP in detail. Other RFCs also apply to various extensions
 to the base protocol. These are referred to in the documentation below
 where relevant.
 
-Python versions 2.7 and 3.4 through 3.9 are officially supported.
+Python versions 3.4 through 3.9 are officially supported.
 
 Getting Started
 ---------------

imapclient/__init__.py

@@ -5,8 +5,6 @@
 # version_info provides the version number in programmer friendly way.
 # The 4th part will be either alpha, beta or final.
 
-from __future__ import unicode_literals
-
 from .imapclient import *
 from .response_parser import *
 from .tls import *

imapclient/config.py

@@ -2,16 +2,13 @@
 # Released subject to the New BSD License
 # Please see http://en.wikipedia.org/wiki/BSD_licenses
 
-from __future__ import unicode_literals
-
 import json
 from os import environ, path
 import ssl
 
-from six import iteritems
-from six.moves.configparser import SafeConfigParser, NoOptionError
-from six.moves.urllib.request import urlopen
-from six.moves.urllib.parse import urlencode
+import configparser
+import urllib.parse
+import urllib.request
 
 import imapclient
 
@@ -45,7 +42,7 @@ def parse_config_file(filename):
     Used by livetest.py and interact.py
     """
 
-    parser = SafeConfigParser(get_string_config_defaults())
+    parser = configparser.SafeConfigParser(get_string_config_defaults())
     with open(filename, "r") as fh:
         parser.readfp(fh)
 
@@ -62,7 +59,7 @@ def parse_config_file(filename):
 
 def get_string_config_defaults():
     out = {}
-    for k, v in iteritems(get_config_defaults()):
+    for k, v in get_config_defaults().items():
         if v is True:
             v = "true"
         elif v is False:
@@ -80,7 +77,7 @@ def _read_config_section(parser, section):
     def get_allowing_none(name, typefunc):
         try:
             v = parser.get(section, name)
-        except NoOptionError:
+        except configparser.NoOptionError:
             return None
         if not v:
             return None
@@ -133,7 +130,8 @@ def refresh_oauth2_token(hostname, client_id, client_secret, refresh_token):
         refresh_token=refresh_token.encode("ascii"),
         grant_type=b"refresh_token",
     )
-    response = urlopen(url, urlencode(post).encode("ascii")).read()
+    response = urllib.request.urlopen(
+        url, urllib.parse.urlencode(post).encode("ascii")).read()
     return json.loads(response.decode("ascii"))["access_token"]
 
 

imapclient/datetime_util.py

@@ -2,8 +2,6 @@
 # Released subject to the New BSD License
 # Please see http://en.wikipedia.org/wiki/BSD_licenses
 
-from __future__ import unicode_literals
-
 import re
 from datetime import datetime
 from email.utils import parsedate_tz

imapclient/fixed_offset.py

@@ -2,8 +2,6 @@
 # Released subject to the New BSD License
 # Please see http://en.wikipedia.org/wiki/BSD_licenses
 
-from __future__ import unicode_literals
-
 import time
 from datetime import tzinfo, timedelta
 

imapclient/imap_utf7.py

@@ -6,10 +6,8 @@
 # base64 encoding context), which is & in this modified UTF-7 convention,
 # since + is considered as mainly used in mailbox names.
 # Other variations and examples can be found in the RFC 3501, section 5.1.3.
-from __future__ import unicode_literals
 
 import binascii
-from six import binary_type, text_type, byte2int, iterbytes, unichr
 
 
 def encode(s):
@@ -18,7 +16,7 @@ def encode(s):
     Input is unicode; output is bytes (Python 3) or str (Python 2). If
     non-unicode input is provided, the input is returned unchanged.
     """
-    if not isinstance(s, text_type):
+    if not isinstance(s, str):
         return s
 
     res = bytearray()
@@ -56,8 +54,8 @@ def consume_b64_buffer(buf):
     return bytes(res)
 
 
-AMPERSAND_ORD = byte2int(b"&")
-DASH_ORD = byte2int(b"-")
+AMPERSAND_ORD = ord("&")
+DASH_ORD = ord("-")
 
 
 def decode(s):
@@ -67,13 +65,13 @@ def decode(s):
     unicode. If non-bytes/str input is provided, the input is returned
     unchanged.
     """
-    if not isinstance(s, binary_type):
+    if not isinstance(s, bytes):
         return s
 
     res = []
     # Store base64 substring that will be decoded once stepping on end shift character
     b64_buffer = bytearray()
-    for c in iterbytes(s):
+    for c in s:
         # Shift character without anything in buffer -> starts storing base64 substring
         if c == AMPERSAND_ORD and not b64_buffer:
             b64_buffer.append(c)
@@ -90,7 +88,7 @@ def decode(s):
             b64_buffer.append(c)
         # No buffer initialized yet, should be an ASCII printable char
         else:
-            res.append(unichr(c))
+            res.append(chr(c))
 
     # Decode the remaining buffer if any
     if b64_buffer: