feat: remove flake8 dependency

blue/__init__.py

@@ -7,6 +7,8 @@
 import re
 import sys
 
+from configparser import ConfigParser
+
 from importlib import machinery
 
 __version__ = '0.9.1'
@@ -86,9 +88,6 @@ def path_hook(cls):
     sub_twice,
 )
 
-from flake8.options import config as flake8_config
-from flake8.options import manager as flake8_manager
-
 from enum import Enum
 from functools import lru_cache
 from typing import Any, Dict, Iterator, List, Optional, Pattern
@@ -393,21 +392,19 @@ def format_file_in_place(*args, **kws):
     return black_format_file_in_place(*args, **kws)
 
 
-try:
-    BaseConfigParser = flake8_config.ConfigParser              # flake8 v4
-except AttributeError:
-    BaseConfigParser = flake8_config.MergedConfigParser        # flake8 v3
+def load_configs_from_file() -> Dict[str, Any]:
+    """Parses supported config files using configparser"""
+    config_dict = {}
+    pwd = Path('.').resolve()
+    supported_config_files = ('setup.cfg', 'tox.ini', '.blue')
+    filenames = [(pwd / config_file) for config_file in supported_config_files]
+    cfg = ConfigParser()
+    cfg.read(filenames)
 
+    if cfg.has_section('blue'):
+        config_dict.update(cfg.items('blue'))
 
-class MergedConfigParser(BaseConfigParser):
-    def _parse_config(self, config_parser, parent=None):
-        """Skip option parsing in flake8's config parsing."""
-        config_dict = {}
-        for option_name in config_parser.options(self.program_name):
-            value = config_parser.get(self.program_name, option_name)
-            LOG.debug('Option "%s" has value: %r', option_name, value)
-            config_dict[option_name] = value
-        return config_dict
+    return config_dict
 
 
 def read_configs(
@@ -416,12 +413,9 @@ def read_configs(
     """Read configs through the config param's callback hook."""
     # Use black's `read_pyproject_toml` for the default
     result = black.read_pyproject_toml(ctx, param, value)
-    # Use flake8's config file parsing to load setup.cfg, tox.ini, and .blue
+    # parses setup.cfg, tox.ini, and .blue config files
     # The parsing looks both in the project and user directories.
-    finder = flake8_config.ConfigFileFinder('blue')
-    manager = flake8_manager.OptionManager('blue', '0')
-    parser = MergedConfigParser(manager, finder)
-    config = parser.parse()
+    config = load_configs_from_file()
     # Merge the configs into Click's `default_map`.
     default_map: Dict[str, Any] = {}
     default_map.update(ctx.default_map or {})

setup.py

@@ -37,7 +37,7 @@ def run_tests(self):
     packages=['blue'],
     tests_require=['tox'],
     cmdclass={'test': Tox},
-    install_requires=['black==22.1.0', 'flake8>=3.8,<5.0.0'],
+    install_requires=['black==22.1.0'],
     project_urls={
         'Documentation': 'https://blue.readthedocs.io/en/latest',
         'Source': 'https://github.com/grantjenks/blue.git',