Merge ~cjwatson/lazr.config:drop-py2 into lazr.config:main

[Colin Watson]

Drop Python 2 support

[Guruprasad (lgp171188)]

LGTM 👍

review: Approve

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 6382dc7..4753587 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -18,6 +18,10 @@ repos:
     -   id: black
         # skip namespace package declaration
         exclude: ^src/lazr/__init__\.py$
+-   repo: https://github.com/asottile/pyupgrade
+    rev: v3.3.1
+    hooks:
+    -   id: pyupgrade
 -   repo: https://github.com/PyCQA/isort
     rev: 5.12.0
     hooks:
diff --git a/NEWS.rst b/NEWS.rst
index d298c85..ea61f16 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -2,14 +2,14 @@
 NEWS for lazr.config
 ====================
 
-2.2.4
-=====
+3.0
+===
 - Add basic pre-commit configuration.
 - Publish Documentation on Read the Docs.
 - Apply inclusive naming via the woke pre-commit hook.
 - Test using ``zope.testrunner`` rather than ``nose``.
 - Officially add support for Python 3.9 and 3.10.
-- Drop support for Python 2.6 and 3.4.
+- Drop support for Python 2.6, 2.7, and 3.4.
 - Apply ``black`` and ``isort``.
 
 2.2.3 (2021-01-26)
diff --git a/pyproject.toml b/pyproject.toml
index a8f43fe..1eb96ee 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,2 +1,3 @@
 [tool.black]
 line-length = 79
+target-version = ["py35"]
diff --git a/setup.py b/setup.py
index 5448a20..f5a5da9 100755
--- a/setup.py
+++ b/setup.py
@@ -61,7 +61,6 @@ files. The format supports schema validation.
         "License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)",  # noqa
         "Operating System :: OS Independent",
         "Programming Language :: Python",
-        "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
@@ -73,4 +72,5 @@ files. The format supports schema validation.
     extras_require=dict(
         docs=["Sphinx"],
     ),
+    python_requires=">=3.5",
 )
diff --git a/src/lazr/config/_config.py b/src/lazr/config/_config.py
index 0f12bf7..b8a56a7 100644
--- a/src/lazr/config/_config.py
+++ b/src/lazr/config/_config.py
@@ -16,9 +16,6 @@
 
 """Implementation classes for config."""
 
-from __future__ import absolute_import, print_function, unicode_literals
-
-__metaclass__ = type
 __all__ = [
     "Config",
     "ConfigData",
@@ -41,7 +38,6 @@ import logging
 import os
 import pwd
 import re
-import sys
 from os.path import abspath, basename, dirname
 from textwrap import dedent
 
@@ -86,7 +82,7 @@ _missing = object()
 
 def read_content(filename):
     """Return the content of a file at filename as a string."""
-    with open(filename, "rt") as fp:
+    with open(filename) as fp:
         return fp.read()
 
 
@@ -111,8 +107,7 @@ class SectionSchema:
 
     def __iter__(self):
         """See `ISectionSchema`"""
-        for key in self._options.keys():
-            yield key
+        yield from self._options.keys()
 
     def __contains__(self, name):
         """See `ISectionSchema`"""
@@ -150,7 +145,7 @@ class Section:
         # Use __dict__ because __getattr__ limits access to self.options.
         self.__dict__["schema"] = schema
         if _options is None:
-            _options = dict((key, schema[key]) for key in schema)
+            _options = {key: schema[key] for key in schema}
         self.__dict__["_options"] = _options
 
     def __getitem__(self, key):
@@ -184,7 +179,7 @@ class Section:
             if key in self._options:
                 self._options[key] = value
             else:
-                msg = "%s does not have a %s key." % (self.name, key)
+                msg = "{} does not have a {} key.".format(self.name, key)
                 errors.append(UnknownKeyError(msg))
         return errors
 
@@ -240,12 +235,12 @@ class ImplicitTypeSection(Section):
 
     def __getitem__(self, key):
         """See `ISection`."""
-        value = super(ImplicitTypeSection, self).__getitem__(key)
+        value = super().__getitem__(key)
         return self._convert(value)
 
     def __getattr__(self, name):
         """See `ISection`."""
-        value = super(ImplicitTypeSection, self).__getattr__(name)
+        value = super().__getattr__(name)
         return self._convert(value)
 
 
@@ -396,8 +391,7 @@ class ConfigSchema:
 
     def __iter__(self):
         """See `IConfigSchema`."""
-        for value in self._section_schemas.values():
-            yield value
+        yield from self._section_schemas.values()
 
     def __contains__(self, name):
         """See `IConfigSchema`."""
@@ -500,8 +494,7 @@ class ConfigData:
 
     def __iter__(self):
         """See `IConfigData`."""
-        for value in self._sections.values():
-            yield value
+        yield from self._sections.values()
 
     def __contains__(self, name):
         """See `IConfigData`."""
@@ -618,16 +611,13 @@ class Config:
         # option and in Python 3.2, this argument changed its default from
         # False to True.  This breaks behavior compatibility with Python 2, so
         # under Python 3, always force strict=False.
-        kws = {}
-        if sys.version_info >= (3,):
-            kws["strict"] = False
-        parser = RawConfigParser(**kws)
+        parser = RawConfigParser(strict=False)
         _parser_read_file(parser, StringIO(conf_data), conf_filename)
         confs.append((conf_filename, parser, encoding_errors))
         if parser.has_option("meta", "extends"):
             base_path = dirname(conf_filename)
             extends_name = parser.get("meta", "extends")
-            extends_filename = abspath("%s/%s" % (base_path, extends_name))
+            extends_filename = abspath("{}/{}".format(base_path, extends_name))
             extends_data = read_content(extends_filename)
             self._getExtendedConfs(extends_filename, extends_data, confs)
         return confs
@@ -676,7 +666,7 @@ class Config:
                 and master_name not in self.schema
             ):
                 # Any section not in the the schema is an error.
-                msg = "%s does not have a %s section." % (
+                msg = "{} does not have a {} section.".format(
                     self.schema.name,
                     section_name,
                 )
@@ -784,7 +774,7 @@ class Category:
 
     def __getattr__(self, name):
         """See `ICategory`."""
-        full_name = "%s.%s" % (self.name, name)
+        full_name = "{}.{}".format(self.name, name)
         if full_name in self._sections:
             return self._sections[full_name]
         raise AttributeError("No section named %s." % name)
@@ -872,10 +862,10 @@ def as_timedelta(value):
     # Complain if the components are out of order.
     if "".join(components) != value:
         raise ValueError
-    keywords = dict(
-        (interval[0].lower(), interval)
+    keywords = {
+        interval[0].lower(): interval
         for interval in ("weeks", "days", "hours", "minutes", "seconds")
-    )
+    }
     keyword_arguments = {}
     for interval in components:
         if len(interval) == 0:
diff --git a/src/lazr/config/_version.py b/src/lazr/config/_version.py
index f394e69..ecd0eec 100644
--- a/src/lazr/config/_version.py
+++ b/src/lazr/config/_version.py
@@ -1 +1 @@
-__version__ = "2.2.3"
+__version__ = "3.0.dev0"
diff --git a/src/lazr/config/docs/conf.py b/src/lazr/config/docs/conf.py
index f9eabe9..160b12a 100644
--- a/src/lazr/config/docs/conf.py
+++ b/src/lazr/config/docs/conf.py
@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-#
 # lazr.config documentation build configuration file, created by
 # sphinx-quickstart on Mon Jan  7 10:37:37 2013.
 #
diff --git a/src/lazr/config/interfaces.py b/src/lazr/config/interfaces.py
index 3c6527e..273c7c3 100644
--- a/src/lazr/config/interfaces.py
+++ b/src/lazr/config/interfaces.py
@@ -17,9 +17,6 @@
 # pylint: disable-msg=E0211,E0213,W0231
 """Interfaces for process configuration.."""
 
-from __future__ import absolute_import, print_function, unicode_literals
-
-__metaclass__ = type
 __all__ = [
     "ConfigErrors",
     "ConfigSchemaError",
@@ -90,7 +87,7 @@ class ConfigErrors(ConfigSchemaError):
         self.errors = errors
 
     def __str__(self):
-        return "%s: %s" % (self.__class__.__name__, self.message)
+        return "{}: {}".format(self.__class__.__name__, self.message)
 
 
 class ISectionSchema(Interface):
diff --git a/src/lazr/config/tests/test_config.py b/src/lazr/config/tests/test_config.py
index 723e3e2..8817325 100644
--- a/src/lazr/config/tests/test_config.py
+++ b/src/lazr/config/tests/test_config.py
@@ -16,9 +16,6 @@
 
 """Tests of lazr.config."""
 
-from __future__ import absolute_import, print_function, unicode_literals
-
-__metaclass__ = type
 __all__ = [
     "TestConfig",
 ]
diff --git a/src/lazr/config/tests/test_docs.py b/src/lazr/config/tests/test_docs.py
index 4c17208..698a94d 100644
--- a/src/lazr/config/tests/test_docs.py
+++ b/src/lazr/config/tests/test_docs.py
@@ -16,9 +16,6 @@
 
 """Test harness for doctests."""
 
-from __future__ import absolute_import, print_function, unicode_literals
-
-__metaclass__ = type
 __all__ = []
 
 import atexit
@@ -49,18 +46,12 @@ def load_tests(loader, tests, pattern):
                     )
                 )
     atexit.register(cleanup_resources)
-    globs = {
-        "absolute_import": absolute_import,
-        "print_function": print_function,
-        "unicode_literals": unicode_literals,
-    }
     tests.addTest(
         doctest.DocFileSuite(
             *doctest_files,
             module_relative=False,
             optionflags=DOCTEST_FLAGS,
-            globs=globs,
-            encoding="UTF-8"
+            encoding="UTF-8",
         )
     )
     return tests
diff --git a/tox.ini b/tox.ini
index 186f2bd..4615990 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,6 @@
 [tox]
 envlist =
     pre-commit
-    py27
     py35
     py36
     py37