Use pre-commit for linting

Also run it in CI. Not adding pyupgrade here, as this will likely be
done in #111.

Aside from reorder-python-imports, I'm not adding any formatters (even
though I truly like black and add-trailing-comma).

.github/workflows/main.yaml

@@ -35,6 +35,27 @@ jobs:
       - name: run tests
         run: python setup.py test
 
+  lint:
+    name: pre-commit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3.0.2
+
+      - uses: actions/setup-python@v4.2.0
+        with:
+          python-version: 3.x
+
+      - name: install pre-commit
+        run: pip install pre-commit
+
+      - name: pre-commit cache
+        uses: actions/cache@v3.0.7
+        with:
+          path: ~/.cache/pre-commit
+          key: "${{ hashFiles('.pre-commit-config.yaml') }}"
+
+      - run: pre-commit run --all-files --show-diff-on-failure
+
   fuzz:
     name: fuzz
     runs-on: ubuntu-latest
@@ -43,7 +64,7 @@ jobs:
 
       - uses: actions/setup-python@v4.2.0
         with:
-          python-version: "3.10"
+          python-version: 3.x
 
       - run: pip install .
 

.pre-commit-config.yaml

@@ -0,0 +1,19 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.3.0
+    hooks:
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+
+  - repo: https://github.com/asottile/reorder_python_imports
+    rev: v3.8.2
+    hooks:
+      - id: reorder-python-imports
+        args:
+          - --py37-plus
+
+  - repo: https://github.com/pycqa/flake8
+    rev: 5.0.4
+    hooks:
+      - id: flake8

.pre-commit-hooks.yaml

@@ -3,4 +3,4 @@
     entry: autoflake
     language: python
     'types': [python]
-    require_serial: true
+    require_serial: true

autoflake.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-
 # Copyright (C) 2012-2019 Steven Myint
 #
 # Permission is hereby granted, free of charge, to any person obtaining
@@ -20,16 +19,10 @@
 # CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
 """Removes unused imports and unused variables as reported by pyflakes."""
-
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import ast
-import difflib
 import collections
-import distutils.sysconfig
+import difflib
 import fnmatch
 import io
 import logging
@@ -40,6 +33,7 @@
 import sys
 import tokenize
 
+import distutils.sysconfig
 import pyflakes.api
 import pyflakes.messages
 import pyflakes.reporter

setup.py

@@ -1,7 +1,5 @@
 #!/usr/bin/env python
-
 """Setup for autoflake."""
-
 import ast
 
 import setuptools

test_autoflake.py

@@ -1,10 +1,6 @@
 #!/usr/bin/env python
 # coding: utf-8
-
 """Test suite for autoflake."""
-
-from __future__ import unicode_literals
-
 import contextlib
 import functools
 import io

test_fuzz.py

@@ -1,15 +1,10 @@
 #!/usr/bin/env python
-
 """Test that autoflake performs correctly on arbitrary Python files.
 
 This checks that autoflake never introduces incorrect syntax. This is
 done by doing a syntax check after the autoflake run. The number of
 Pyflakes warnings is also confirmed to always improve.
 """
-
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import os
 import shlex
 import subprocess

test_fuzz_pypi.py

@@ -1,11 +1,5 @@
 #!/usr/bin/env python
-
 """Fuzz test against the latest packages on PyPI."""
-
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import os
 import subprocess
 import sys