refactor: drop support for Python 3.6

Author: Rogdham

.github/workflows/build.yml

@@ -11,13 +11,11 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.6"
           - "3.7"
           - "3.8"
           - "3.9"
           - "3.10"
           - "3.11"
-          - "pypy-3.6"
           - "pypy-3.7"
           - "pypy-3.8"
           - "pypy-3.9"

CHANGELOG.md

@@ -9,6 +9,10 @@ adheres to [Semantic Versioning](https://semver.org/).
 
 [unreleased]: https://github.com/rogdham/python-xz/compare/v0.4.0...HEAD
 
+### :boom: Breaking changes
+
+- End of Python 3.6 support
+
 ### :house: Internal
 
 - Necessary code changes following dev dependency update: black, pylint, pytest

README.md

@@ -179,10 +179,7 @@ As a general rule, all Python versions that are both [released and still officia
 supported][python-versions] are supported by `python-xz` and tested against (both
 CPython and PyPy implementations).
 
-Moreover, Python 3.6 is currently supported as well, but may be dropped in future
-releases.
-
 If you have other use cases or find issues with some Python versions, feel free to
 [open a ticket](https://github.com/Rogdham/python-xz/issues/new)!
 
-[python-versions]: https://devguide.python.org/#status-of-python-branches
+[python-versions]: https://devguide.python.org/versions/#versions

pytest.ini

@@ -4,7 +4,7 @@ addopts =
     --strict-markers
 filterwarnings =
     error
-    # issue in standard lib for Python 3.7.12[pypy-7.3.6-final]
+    # issue in standard lib for PyPy < 3.9
     ignore:Using or importing the ABCs from 'collections':DeprecationWarning:_lzma
 markers =
     generate_integration_files

setup.cfg

@@ -19,7 +19,6 @@ classifiers =
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
@@ -33,7 +32,7 @@ classifiers =
 include_package_data = True
 package_dir = =src
 packages = xz
-python_requires = >=3.6
+python_requires = >=3.7
 setup_requires =
     setuptools_scm
     wheel

src/xz/typing.py

@@ -8,15 +8,10 @@
 else:  # pragma: no cover
     _LZMAFilenameType = Union[str, bytes, PathLike, BinaryIO]
 
-    # ducktype Literal (NB we cannot use __class_getitem__ on Python 3.6)
-    # we could require typing-extensions package but that's hardly an improvement
-
-    class LiteralKlass:
-        def __getitem__(self, items: Any) -> str:
+    class Literal:
+        def __class_getitem__(cls, items: Any) -> str:
             return f"Literal{list(items)}"
 
-    Literal = LiteralKlass()
-
 
 if sys.version_info >= (3, 8):  # pragma: no cover
     from typing import Protocol

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py, py36, py37, py38, py39, py310, py311, pypy3
+    py, py37, py38, py39, py310, py311, pypy3
     generate-integration-files, type, lint, format
 
 [testenv]