Remove the remaining Python 2 idioms #267

Part of the repository modernization effort.

Background

The code holds Python 2 idioms outside of six and bmemcached/compat.py. Each one is dead on Python 3.

Work items

Dead import fallbacks

bmemcached/protocol.py:6-8:

try:
    from urlparse import SplitResult  # type: ignore[import-not-found]
except ImportError:
    from urllib.parse import SplitResult

Replace with from urllib.parse import SplitResult. This also removes a # type: ignore comment.

test/test_pickler.py:6-9:

try:
    import cPickle as pickle
except ImportError:
    import pickle

Replace with import pickle.

Old-style super() calls

• bmemcached/protocol.py:106 — super(Protocol, self).__init__()
• bmemcached/client/distributed.py:17 — super(DistributedClient, self).__init__(...)
• test/test_error_handling.py:15 — super(_CacheProxy, self).__init__()

Change each call to super().__init__(...).

Redundant object base class

• bmemcached/client/mixin.py:8 — class ClientMixin(object):
• test/test_pickler.py:15,19 — class PickleableThing(object):, class JsonPickler(object):

Drop the explicit (object) base.

Dead string prefixes and headers

• docs/conf.py:1 — the # -*- coding: utf-8 -*- header. UTF-8 is the default source encoding on Python 3.
• docs/conf.py:45,46,191,192,221,222,235,236 — u'...' prefixes.
• test/test_simple_functions.py:77,78,246,247,406,436,593,594,686,687 — u'...' prefixes.

Do not change

Do not convert logger.debug('...%s...', arg) calls to f-strings. Sites include bmemcached/protocol.py:302,454,471,593,595,964,980,992. The logging module formats these lazily. An f-string forces eager formatting even when the log level is off.

Not found in this repository

A scan found no basestring, no has_key, no iteritems, no except X, e:, and no from __future__ import. No work is needed for these.

Acceptance criteria

• No try/except ImportError import fallback stays in bmemcached/ or test/.
• Every super() call uses the zero-argument form.
• No class declares an explicit object base.
• No u'...' prefix and no coding header stays in the listed files.
• logger.debug calls keep lazy % arguments.
• Behavior does not change. The full test suite passes.

Files to change

bmemcached/protocol.py, bmemcached/client/mixin.py, bmemcached/client/distributed.py, test/test_pickler.py, test/test_error_handling.py, test/test_simple_functions.py, docs/conf.py.

Order

Do the six removal issue first. The two issues touch the same lines in bmemcached/protocol.py.