Remove support for end-of-life Pythons

Match pip support Pythons and remove support for end-of-life Pythons.
pip has not support Python 2 since 21.0 (2021-01-23). For dates on when
these environments went EOL, see:

https://devguide.python.org/devcycle/#end-of-life-branches

Removing support for Python2 allows for several simplifications:

- Remove use of toml package in favor of tomli
- Remove compat.py
- Replace io.open with builtin open
- Replace tempdir function with tempfile.TemporaryDirectory
- Replace mkdir_p function with os.makedirs
- Remove use of mock package in favor of unittest.mock
- Remove import from future module
- Remove unnecessary inheritance from object

Refs #90

.github/workflows/tests.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["2.7", "3.5", "3.6", "3.7", "3.8", "3.9", "3.10"]
+        python-version: ["3.6", "3.7", "3.8", "3.9", "3.10"]
         os: [ubuntu-latest, macos-latest, windows-latest]
 
     steps:

dev-requirements.txt

@@ -1,11 +1,8 @@
 pytest
 pytest-flake8
 flake8 < 4  # https://github.com/tholo/pytest-flake8/issues/81
-pytest-forward-compatibility; python_version<'3'
-mock ; python_version<'3.6'
 testpath
-toml ; python_version<'3.6'
-tomli ; python_version>='3.6'
+tomli
 setuptools>=30
 importlib_metadata ; python_version<'3.8'
 zipp ; python_version<'3.8'

doc/changelog.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+UNRELEASED
+----------
+
+- Remove support for end-of-life Pythons. Now requires Python3.6+.
+- Remove support for ``toml`` package. Now requires ``tomli``.
+
 0.12
 ----
 

doc/requirements.txt

@@ -1,2 +1 @@
-toml ; python_version<'3.6'
-tomli ; python_version>='3.6'
+tomli

pep517/build.py

@@ -1,13 +1,13 @@
 """Build a project using PEP 517 hooks.
 """
 import argparse
-import io
 import logging
 import os
 import shutil
+import tempfile
+
+import tomli
 
-from .compat import FileNotFoundError, toml_load
-from .dirtools import mkdir_p, tempdir
 from .envbuild import BuildEnvironment
 from .wrappers import Pep517HookCaller
 
@@ -31,8 +31,8 @@ def load_system(source_dir):
     Load the build system from a source dir (pyproject.toml).
     """
     pyproject = os.path.join(source_dir, 'pyproject.toml')
-    with io.open(pyproject, 'rb') as f:
-        pyproject_data = toml_load(f)
+    with open(pyproject, 'rb') as f:
+        pyproject_data = tomli.load(f)
     return pyproject_data['build-system']
 
 
@@ -64,7 +64,7 @@ def _do_build(hooks, env, dist, dest):
     env.pip_install(reqs)
     log.info('Installed dynamic build dependencies')
 
-    with tempdir() as td:
+    with tempfile.TemporaryDirectory() as td:
         log.info('Trying to build %s in %s', dist, td)
         build_name = 'build_{dist}'.format(**locals())
         build = getattr(hooks, build_name)
@@ -76,7 +76,7 @@ def _do_build(hooks, env, dist, dest):
 def build(source_dir, dist, dest=None, system=None):
     system = system or load_system(source_dir)
     dest = os.path.join(source_dir, dest or 'dist')
-    mkdir_p(dest)
+    os.makedirs(dest, exist_ok=True)
 
     validate_system(system)
     hooks = Pep517HookCaller(

pep517/check.py

@@ -1,7 +1,6 @@
 """Check a project and backend by attempting to build using PEP 517 hooks.
 """
 import argparse
-import io
 import logging
 import os
 import shutil
@@ -13,8 +12,9 @@ from os.path import join as pjoin
 from subprocess import CalledProcessError
 from tempfile import mkdtemp
 
+import tomli
+
 from .colorlog import enable_colourful_output
-from .compat import TOMLDecodeError, toml_load
 from .envbuild import BuildEnvironment
 from .wrappers import Pep517HookCaller
 
@@ -143,15 +143,15 @@ def check(source_dir):
         return False
 
     try:
-        with io.open(pyproject, 'rb') as f:
-            pyproject_data = toml_load(f)
+        with open(pyproject, 'rb') as f:
+            pyproject_data = tomli.load(f)
         # Ensure the mandatory data can be loaded
         buildsys = pyproject_data['build-system']
         requires = buildsys['requires']
         backend = buildsys['build-backend']
         backend_path = buildsys.get('backend-path')
         log.info('Loaded pyproject.toml')
-    except (TOMLDecodeError, KeyError):
+    except (tomli.TOMLDecodeError, KeyError):
         log.error("Invalid pyproject.toml", exc_info=True)
         return False
 

pep517/colorlog.py

@@ -73,8 +73,6 @@ class LogFormatter(logging.Formatter):
             # right conversion in python 3.
             fg_color = (curses.tigetstr("setaf") or
                         curses.tigetstr("setf") or "")
-            if (3, 0) < sys.version_info < (3, 2, 3):
-                fg_color = str(fg_color, "ascii")
 
             for levelno, code in self.DEFAULT_COLORS.items():
                 self._colors[levelno] = str(

pep517/compat.py

@@ -1,50 +0,0 @@
-"""Python 2/3 compatibility"""
-import io
-import json
-import sys
-
-# Handle reading and writing JSON in UTF-8, on Python 3 and 2.
-
-if sys.version_info[0] >= 3:
-    # Python 3
-    def write_json(obj, path, **kwargs):
-        with open(path, 'w', encoding='utf-8') as f:
-            json.dump(obj, f, **kwargs)
-
-    def read_json(path):
-        with open(path, 'r', encoding='utf-8') as f:
-            return json.load(f)
-
-else:
-    # Python 2
-    def write_json(obj, path, **kwargs):
-        with open(path, 'wb') as f:
-            json.dump(obj, f, encoding='utf-8', **kwargs)
-
-    def read_json(path):
-        with open(path, 'rb') as f:
-            return json.load(f)
-
-
-# FileNotFoundError
-
-try:
-    FileNotFoundError = FileNotFoundError
-except NameError:
-    FileNotFoundError = IOError
-
-
-if sys.version_info < (3, 6):
-    from toml import load as _toml_load  # noqa: F401
-
-    def toml_load(f):
-        w = io.TextIOWrapper(f, encoding="utf8", newline="")
-        try:
-            return _toml_load(w)
-        finally:
-            w.detach()
-
-    from toml import TomlDecodeError as TOMLDecodeError  # noqa: F401
-else:
-    from tomli import TOMLDecodeError  # noqa: F401
-    from tomli import load as toml_load  # noqa: F401

pep517/dirtools.py

@@ -1,33 +1,8 @@
-import contextlib
-import errno
 import io
 import os
-import shutil
-import tempfile
 import zipfile
 
 
-@contextlib.contextmanager
-def tempdir():
-    """Create a temporary directory in a context manager."""
-    td = tempfile.mkdtemp()
-    try:
-        yield td
-    finally:
-        shutil.rmtree(td)
-
-
-def mkdir_p(*args, **kwargs):
-    """Like `mkdir`, but does not raise an exception if the
-    directory already exists.
-    """
-    try:
-        return os.mkdir(*args, **kwargs)
-    except OSError as exc:
-        if exc.errno != errno.EEXIST:
-            raise
-
-
 def dir_to_zipfile(root):
     """Construct an in-memory zip file for a directory."""
     buffer = io.BytesIO()

pep517/envbuild.py

@@ -1,7 +1,6 @@
 """Build wheels/sdists by installing build deps to a temporary environment.
 """
 
-import io
 import logging
 import os
 import shutil
@@ -10,18 +9,19 @@ from subprocess import check_call
 from sysconfig import get_paths
 from tempfile import mkdtemp
 
-from .compat import toml_load
+import tomli
+
 from .wrappers import LoggerWrapper, Pep517HookCaller
 
 log = logging.getLogger(__name__)
 
 
 def _load_pyproject(source_dir):
-    with io.open(
+    with open(
             os.path.join(source_dir, 'pyproject.toml'),
             'rb',
             ) as f:
-        pyproject_data = toml_load(f)
+        pyproject_data = tomli.load(f)
     buildsys = pyproject_data['build-system']
     return (
         buildsys['requires'],
@@ -30,7 +30,7 @@ def _load_pyproject(source_dir):
     )
 
 
-class BuildEnvironment(object):
+class BuildEnvironment:
     """Context manager to install build deps in a simple temporary environment
 
     Based on code I wrote for pip, which is MIT licensed.

pep517/in_process/_in_process.py

@@ -23,30 +23,18 @@ from glob import glob
 from importlib import import_module
 from os.path import join as pjoin
 
-# This file is run as a script, and `import compat` is not zip-safe, so we
-# include write_json() and read_json() from compat.py.
-#
-# Handle reading and writing JSON in UTF-8, on Python 3 and 2.
+# This file is run as a script, and `import wrappers` is not zip-safe, so we
+# include write_json() and read_json() from wrappers.py.
 
-if sys.version_info[0] >= 3:
-    # Python 3
-    def write_json(obj, path, **kwargs):
-        with open(path, 'w', encoding='utf-8') as f:
-            json.dump(obj, f, **kwargs)
 
-    def read_json(path):
-        with open(path, 'r', encoding='utf-8') as f:
-            return json.load(f)
+def write_json(obj, path, **kwargs):
+    with open(path, 'w', encoding='utf-8') as f:
+        json.dump(obj, f, **kwargs)
 
-else:
-    # Python 2
-    def write_json(obj, path, **kwargs):
-        with open(path, 'wb') as f:
-            json.dump(obj, f, encoding='utf-8', **kwargs)
 
-    def read_json(path):
-        with open(path, 'rb') as f:
-            return json.load(f)
+def read_json(path):
+    with open(path, encoding='utf-8') as f:
+        return json.load(f)
 
 
 class BackendUnavailable(Exception):
@@ -64,7 +52,7 @@ class BackendInvalid(Exception):
 class HookMissing(Exception):
     """Raised if a hook is missing and we are not executing the fallback"""
     def __init__(self, hook_name=None):
-        super(HookMissing, self).__init__(hook_name)
+        super().__init__(hook_name)
         self.hook_name = hook_name
 
 

pep517/meta.py

@@ -5,6 +5,7 @@ import functools
 import logging
 import os
 import shutil
+import tempfile
 
 try:
     import importlib.metadata as imp_meta
@@ -17,7 +18,7 @@ except ImportError:
     from zipp import Path
 
 from .build import compat_system, load_system, validate_system
-from .dirtools import dir_to_zipfile, mkdir_p, tempdir
+from .dirtools import dir_to_zipfile
 from .envbuild import BuildEnvironment
 from .wrappers import Pep517HookCaller, quiet_subprocess_runner
 
@@ -31,7 +32,7 @@ def _prep_meta(hooks, env, dest):
     env.pip_install(reqs)
     log.info('Installed dynamic build dependencies')
 
-    with tempdir() as td:
+    with tempfile.TemporaryDirectory() as td:
         log.info('Trying to build metadata in %s', td)
         filename = hooks.prepare_metadata_for_build_wheel(td, {})
         source = os.path.join(td, filename)
@@ -41,7 +42,7 @@ def _prep_meta(hooks, env, dest):
 def build(source_dir='.', dest=None, system=None):
     system = system or load_system(source_dir)
     dest = os.path.join(source_dir, dest or 'dist')
-    mkdir_p(dest)
+    os.makedirs(dest, exist_ok=True)
     validate_system(system)
     hooks = Pep517HookCaller(
         source_dir, system['build-backend'], system.get('backend-path')
@@ -54,7 +55,7 @@ def build(source_dir='.', dest=None, system=None):
 
 
 def build_as_zip(builder=build):
-    with tempdir() as out_dir:
+    with tempfile.TemporaryDirectory() as out_dir:
         builder(dest=out_dir)
         return dir_to_zipfile(out_dir)
 

pep517/wrappers.py

@@ -1,14 +1,13 @@
+import json
 import os
-import shutil
 import sys
+import tempfile
 import threading
 from contextlib import contextmanager
 from os.path import abspath
 from os.path import join as pjoin
 from subprocess import STDOUT, check_call, check_output
-from tempfile import mkdtemp
 
-from . import compat
 from .in_process import _in_proc_script_path
 
 __all__ = [
@@ -22,13 +21,14 @@ __all__ = [
 ]
 
 
-@contextmanager
-def tempdir():
-    td = mkdtemp()
-    try:
-        yield td
-    finally:
-        shutil.rmtree(td)
+def write_json(obj, path, **kwargs):
+    with open(path, 'w', encoding='utf-8') as f:
+        json.dump(obj, f, **kwargs)
+
+
+def read_json(path):
+    with open(path, encoding='utf-8') as f:
+        return json.load(f)
 
 
 class BackendUnavailable(Exception):
@@ -48,7 +48,7 @@ class BackendInvalid(Exception):
 class HookMissing(Exception):
     """Will be raised on missing hooks."""
     def __init__(self, hook_name):
-        super(HookMissing, self).__init__(hook_name)
+        super().__init__(hook_name)
         self.hook_name = hook_name
 
 
@@ -100,7 +100,7 @@ def norm_and_check(source_tree, requested):
     return abs_requested
 
 
-class Pep517HookCaller(object):
+class Pep517HookCaller:
     """A wrapper around a source directory to be built with a PEP 517 backend.
 
     :param source_dir: The path to the source directory, containing
@@ -293,29 +293,15 @@ class Pep517HookCaller(object):
         })
 
     def _call_hook(self, hook_name, kwargs):
-        # On Python 2, pytoml returns Unicode values (which is correct) but the
-        # environment passed to check_call needs to contain string values. We
-        # convert here by encoding using ASCII (the backend can only contain
-        # letters, digits and _, . and : characters, and will be used as a
-        # Python identifier, so non-ASCII content is wrong on Python 2 in
-        # any case).
-        # For backend_path, we use sys.getfilesystemencoding.
-        if sys.version_info[0] == 2:
-            build_backend = self.build_backend.encode('ASCII')
-        else:
-            build_backend = self.build_backend
-        extra_environ = {'PEP517_BUILD_BACKEND': build_backend}
+        extra_environ = {'PEP517_BUILD_BACKEND': self.build_backend}
 
         if self.backend_path:
             backend_path = os.pathsep.join(self.backend_path)
-            if sys.version_info[0] == 2:
-                backend_path = backend_path.encode(sys.getfilesystemencoding())
             extra_environ['PEP517_BACKEND_PATH'] = backend_path
 
-        with tempdir() as td:
+        with tempfile.TemporaryDirectory() as td:
             hook_input = {'kwargs': kwargs}
-            compat.write_json(hook_input, pjoin(td, 'input.json'),
-                              indent=2)
+            write_json(hook_input, pjoin(td, 'input.json'), indent=2)
 
             # Run the hook in a subprocess
             with _in_proc_script_path() as script:
@@ -326,7 +312,7 @@ class Pep517HookCaller(object):
                     extra_environ=extra_environ
                 )
 
-            data = compat.read_json(pjoin(td, 'output.json'))
+            data = read_json(pjoin(td, 'output.json'))
             if data.get('unsupported'):
                 raise UnsupportedOperation(data.get('traceback', ''))
             if data.get('no_backend'):

pyproject.toml

@@ -9,15 +9,15 @@ author-email = "thomas@kluyver.me.uk"
 home-page = "https://github.com/pypa/pep517"
 description-file = "README.rst"
 requires = [
-    "toml;python_version<'3.6'",
-    "tomli >=1.1.0;python_version>='3.6'",
+    "tomli >=1.1.0",
     "importlib_metadata;python_version<'3.8'",
     "zipp;python_version<'3.8'",
 ]
+requires-python = ">=3.6"
 classifiers = [
     "License :: OSI Approved :: MIT License",
-    "Programming Language :: Python :: 2.7",
     "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
 ]
 
 [tool.isort]

tests/test_call_hooks.py

@@ -1,22 +1,16 @@
-import io
 import json
 import os
-import sys
 import tarfile
 import zipfile
 from os.path import abspath, dirname
 from os.path import join as pjoin
+from unittest.mock import Mock
 
 import pytest
+import tomli
 from testpath import assert_isfile, modified_env
 from testpath.tempdir import TemporaryDirectory, TemporaryWorkingDirectory
 
-try:
-    from mock import Mock  # Prefer the backport below python 3.6
-except ImportError:
-    from unittest.mock import Mock
-
-from pep517.compat import toml_load
 from pep517.wrappers import (
     BackendUnavailable,
     Pep517HookCaller,
@@ -24,18 +18,14 @@ from pep517.wrappers import (
     default_subprocess_runner,
 )
 
-if sys.version_info[0] == 2:
-    FileNotFoundError = IOError
-
-
 SAMPLES_DIR = pjoin(dirname(abspath(__file__)), 'samples')
 BUILDSYS_PKGS = pjoin(SAMPLES_DIR, 'buildsys_pkgs')
 
 
 def get_hooks(pkg, **kwargs):
     source_dir = pjoin(SAMPLES_DIR, pkg)
-    with io.open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
-        data = toml_load(f)
+    with open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
+        data = tomli.load(f)
     return Pep517HookCaller(
         source_dir, data['build-system']['build-backend'], **kwargs
     )

tests/test_envbuild.py

@@ -1,17 +1,12 @@
 import tarfile
+import zipfile
 from os.path import abspath, dirname
 from os.path import join as pjoin
+from unittest.mock import call, patch
 
 from testpath import assert_isfile, modified_env
 from testpath.tempdir import TemporaryDirectory
 
-try:
-    from unittest.mock import call, patch
-except ImportError:
-    from mock import patch, call  # Python 2 fallback
-
-import zipfile
-
 from pep517.envbuild import BuildEnvironment, build_sdist, build_wheel
 
 SAMPLES_DIR = pjoin(dirname(abspath(__file__)), 'samples')

tests/test_hook_fallbacks.py

@@ -1,12 +1,11 @@
-import io
 from os.path import abspath, dirname
 from os.path import join as pjoin
 
 import pytest
+import tomli
 from testpath import assert_isfile, modified_env
 from testpath.tempdir import TemporaryDirectory
 
-from pep517.compat import toml_load
 from pep517.wrappers import HookMissing, Pep517HookCaller
 
 SAMPLES_DIR = pjoin(dirname(abspath(__file__)), 'samples')
@@ -15,8 +14,8 @@ BUILDSYS_PKGS = pjoin(SAMPLES_DIR, 'buildsys_pkgs')
 
 def get_hooks(pkg):
     source_dir = pjoin(SAMPLES_DIR, pkg)
-    with io.open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
-        data = toml_load(f)
+    with open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
+        data = tomli.load(f)
     return Pep517HookCaller(source_dir, data['build-system']['build-backend'])
 
 

tests/test_inplace_hooks.py

@@ -1,11 +1,10 @@
-import io
 from os.path import abspath, dirname
 from os.path import join as pjoin
 
 import pytest
+import tomli
 from testpath import modified_env
 
-from pep517.compat import toml_load
 from pep517.wrappers import BackendInvalid, Pep517HookCaller
 
 SAMPLES_DIR = pjoin(dirname(abspath(__file__)), 'samples')
@@ -15,8 +14,8 @@ SOURCE_DIR = pjoin(SAMPLES_DIR, 'pkg1')
 
 def get_hooks(pkg, backend=None, path=None):
     source_dir = pjoin(SAMPLES_DIR, pkg)
-    with io.open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
-        data = toml_load(f)
+    with open(pjoin(source_dir, 'pyproject.toml'), 'rb') as f:
+        data = tomli.load(f)
     if backend is None:
         backend = data['build-system']['build-backend']
     if path is None:

tests/test_meta.py

@@ -1,16 +1,7 @@
-from __future__ import absolute_import, division, unicode_literals
-
 import re
 
-import pytest
-
 from pep517 import meta
 
-pep517_needs_python_3 = pytest.mark.xfail(
-    'sys.version_info < (3,)',
-    reason="pep517 cannot be built on Python 2",
-)
-
 
 def test_meta_for_this_package():
     dist = meta.load('.')

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py34, py35, py36, py37, py38, py39, py310, pypy, pypy3, isort
+envlist = py36, py37, py38, py39, py310, pypy3, isort
 skipsdist = true
 
 [testenv]