feature/BLACK_CONFIG: Black configuration file configurable

README.rst

@@ -144,6 +144,9 @@ Version History
 ======= ============ ===========================================================
 Version Release date   Changes
 ------- ------------ -----------------------------------------------------------
+v0.1.1  2019-08-06   - Option to use a (global) black configuration file,
+                       contribution from
+                       `Tomasz Grining <https://github.com/098799>`_.
 v0.1.0  2019-06-03   - Uses main ``black`` settings from ``pyproject.toml``,
                        contribution from `Alex <https://github.com/ADKosm>`_.
                      - WARNING: Now ignores ``flake8`` max-line-length setting.

flake8_black.py

@@ -3,6 +3,8 @@
 This is a plugin for the tool flake8 tool for checking Python
 soucre code using the tool black.
 """
+from functools import lru_cache
+from os import path
 from pathlib import Path
 
 import black
@@ -11,7 +13,7 @@
 from flake8 import utils as stdin_utils
 
 
-__version__ = "0.1.0"
+__version__ = "0.1.1"
 
 black_prefix = "BLK"
 
@@ -52,17 +54,30 @@ def __init__(self, tree, filename="(none)", builtins=None):
         # see property self._file_mode for new black versions:
         self.file_mode = 0  # was: black.FileMode.AUTO_DETECT
 
-    def _load_black_config(self):
+    @property
+    @lru_cache()
+    def config_file(self):
+        """File path to the black configuration file."""
+        if self.flake8_black_config:
+            flake8_black_path = Path(self.flake8_black_config)
+
+            if self.flake8_config:
+                flake8_config_path = path.dirname(path.abspath(self.flake8_config))
+                return Path(flake8_config_path) / flake8_black_path
+
+            return flake8_black_path
+
         source_path = (
             self.filename
             if self.filename not in self.STDIN_NAMES
             else Path.cwd().as_posix()
         )
         project_root = black.find_project_root((Path(source_path),))
-        path = project_root / "pyproject.toml"
+        return project_root / "pyproject.toml"
 
-        if path.is_file():
-            pyproject_toml = toml.load(str(path))
+    def _load_black_config(self):
+        if self.config_file.is_file():
+            pyproject_toml = toml.load(str(self.config_file))
             config = pyproject_toml.get("tool", {}).get("black", {})
             return {k.replace("--", "").replace("-", "_"): v for k, v in config.items()}
         return None
@@ -98,6 +113,27 @@ def _file_mode(self):
             assert "got an unexpected keyword argument" in str(e), e
             return None
 
+    @classmethod
+    def add_options(cls, parser):
+        """Adding black-config option."""
+        parser.add_option(
+            "--black-config",
+            default=None,
+            action="store",
+            type="string",
+            parse_from_config=True,
+            help=(
+                "Path to black configuration file"
+                "(overrides the default pyproject.toml)",
+            ),
+        )
+
+    @classmethod
+    def parse_options(cls, options):
+        """Adding black-config option."""
+        cls.flake8_black_config = options.black_config
+        cls.flake8_config = options.config
+
     def run(self):
         """Use black to check code style."""
         msg = None

tests/flake8_config/flake8

@@ -0,0 +1,2 @@
+[flake8]
+black-config = ../with_pyproject_toml/pyproject.toml

tests/run_tests.sh

@@ -9,6 +9,7 @@ flake8 --select BLK test_cases/*.py
 flake8 --select BLK --max-line-length 50 test_cases/*.py
 flake8 --select BLK --max-line-length 90 test_cases/*.py
 flake8 --select BLK with_pyproject_toml/*.py
+flake8 --select BLK without_pyproject_toml/*.py --config=flake8_config/flake8
 flake8 --select BLK --max-line-length 88 with_pyproject_toml/
 flake8 --select BLK non_conflicting_configurations/*.py
 flake8 --select BLK conflicting_configurations/*.py

tests/without_pyproject_toml/ordinary_quotes.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""Print 'Hello world' to the terminal.
+
+This is a simple test script using a hashbang line
+and a PEP263 encoding line.
+We use ordinary quotes in this test.
+"""
+
+print('Hello world')