add black/isort configuration

.git-blame-ignore-revs

@@ -0,0 +1 @@
+<insert format ref here>

.github/workflows/test.yml

@@ -86,7 +86,7 @@ jobs:
           arch: x64
           os: windows-latest
           toxenv: type
-        - name: Code style with flake8
+        - name: Formatting with Black + isort and code style with flake8
           python: '3.7'
           arch: x64
           os: ubuntu-latest

.gitignore

@@ -9,7 +9,7 @@ docs/source/_build
 mypyc/doc/_build
 *.iml
 /out/
-.venv
+.venv*
 venv/
 .mypy_cache/
 .incremental_checker_cache.json

.pre-commit-config.yaml

@@ -0,0 +1,9 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: 22.6.0  # must match test-requirements.txt
+    hooks:
+      - id: black
+  - repo: https://github.com/pycqa/isort
+    rev: 5.10.1  # must match test-requirements.txt
+    hooks:
+      - id: isort

README.md

@@ -9,7 +9,8 @@ Mypy: Static Typing for Python
 [![Documentation Status](https://readthedocs.org/projects/mypy/badge/?version=latest)](https://mypy.readthedocs.io/en/latest/?badge=latest)
 [![Chat at https://gitter.im/python/typing](https://badges.gitter.im/python/typing.svg)](https://gitter.im/python/typing?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Checked with mypy](http://www.mypy-lang.org/static/mypy_badge.svg)](http://mypy-lang.org/)
-
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg")](https://github.com/psf/black)
+[![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=flat&labelColor=ef8336)](https://pycqa.github.io/isort/)
 
 Got a question?
 ---------------

pyproject.toml

@@ -4,3 +4,24 @@ requires = [
     "wheel >= 0.30.0",
 ]
 build-backend = "setuptools.build_meta"
+
+[tool.black]
+line-length = 99
+target-version = ['py37']
+skip-magic-trailing-comma = true
+extend-exclude = '''
+^/mypy/typeshed|
+^/mypyc/test-data|
+^/test-data
+'''
+
+[tool.isort]
+profile = "black"
+line_length = 99
+combine_as_imports = true
+skip_gitignore = true
+skip = [
+    "mypy/typeshed",
+    "mypyc/test-data",
+    "test-data",
+]

runtests.py

@@ -52,8 +52,10 @@
     'self': [executable, '-m', 'mypy', '--config-file', 'mypy_self_check.ini', '-p', 'mypy'],
     # Lint
     'lint': ['flake8', '-j0'],
+    "format-black": ["black", "."],
+    "format-isort": ["isort", "."],
     # Fast test cases only (this is the bulk of the test suite)
-    'pytest-fast': ['pytest', '-q', '-k', 'not (%s)' % ' or '.join(ALL_NON_FAST)],
+    'pytest-fast': ['pytest', '-q', '-k', f"not ({' or '.join(ALL_NON_FAST)})"],
     # Test cases that invoke mypy (with small inputs)
     'pytest-cmdline': ['pytest', '-q', '-k', ' or '.join([CMDLINE,
                                                           EVALUATION,
@@ -118,7 +120,7 @@ def wait_background_cmd(name: str, proc: Popen) -> int:
     print(f'run {name}: {cmds[name]}')
     if status:
         print(output.decode().rstrip())
-        print('\nFAILED: %s' % name)
+        print("\nFAILED:", name)
         if name in FAST_FAIL:
             exit(status)
     return status
@@ -128,7 +130,7 @@ def main() -> None:
     prog, *args = argv
 
     if not set(args).issubset(cmds):
-        print("usage:", prog, " ".join('[%s]' % k for k in cmds))
+        print("usage:", prog, " ".join(f"[{k}]" for k in cmds))
         print()
         print('Run the given tests. If given no arguments, run everything except'
               + ' pytest-extra and mypyc-extra.')

setup.cfg

@@ -34,6 +34,8 @@ exclude =
 
 # Things to ignore:
 #   E128: continuation line under-indented (too noisy)
+#   E203: conflicts with black
+#   E501: conflicts with black
 #   W601: has_key() deprecated (false positives)
 #   E701: multiple statements on one line (colon) (we use this for classes with empty body)
 #   E704: multiple statements on one line (def)
@@ -44,7 +46,7 @@ exclude =
 #   B011: Don't use assert False
 #   F821: Name not defined (generates false positives with error codes)
 #   E741: Ambiguous variable name
-extend-ignore = E128,W601,E701,E704,E402,B3,B006,B007,B011,F821,E741
+extend-ignore = E128,E203,E501,W601,E701,E704,E402,B3,B006,B007,B011,F821,E741
 
 [coverage:run]
 branch = true

test-requirements.txt

@@ -1,11 +1,13 @@
 -r mypy-requirements.txt
 -r build-requirements.txt
 attrs>=18.0
+black==22.6.0  # must match version in .pre-commit-config.yaml
 filelock>=3.3.0,<3.4.2; python_version<'3.7'
 filelock>=3.3.0; python_version>='3.7'
 flake8==3.9.2
 flake8-bugbear==22.3.20
 flake8-pyi>=20.5
+isort[colors]==5.10.1  # must match version in .pre-commit-config.yaml
 lxml>=4.4.0; python_version<'3.11'
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10

tox.ini

@@ -47,7 +47,10 @@ parallel_show_output = True
 
 [testenv:lint]
 description = check the code style
-commands = flake8 {posargs}
+commands =
+    flake8 {posargs}
+    black --check --diff --color .
+    isort --check --diff --color .
 
 [testenv:type]
 description = type check ourselves