Per-file exceptions support

docs/config.md

@@ -16,6 +16,23 @@ Key can be exact plugin name or wildcard template. For example `"flake8-commas"`
 
 Value is a list of templates for error codes for this plugin. First symbol in every template must be `+` (include) or `-` (exclude). The latest matched pattern wins. For example, `["+*", "-F*", "-E30?", "-E401"]` means "Include everything except all checks that starts with `F`, check from `E301` to `E310`, and `E401`".
 
+## Exceptions
+
+Use `exceptions` section to specify special rules for particular paths:
+
+```toml
+[tool.flakehell.plugins]
+pycodestyle = ["+*"]
+pyflakes = ["+*"]
+
+[tool.flakehell.exceptions."tests/"]
+pycodestyle = ["-F401"]     # disable a check
+pyflakes = ["-*"]           # disable a plugin
+
+[tool.flakehell.exceptions."tests/test_example.py"]
+pyflakes = ["+*"]           # enable a plugin
+```
+
 ## Base
 
 Option `base` allows to specify base config from which you want to inherit this one. It can be path to local config or remote URL. You can specify one path or list of paths as well. For example:
@@ -63,6 +80,15 @@ flake8-bandit = ["-*", "+S1??"]
 "flake8-*" = ["+*"]
 # explicitly disable plugin
 flake8-docstrings = ["-*"]
+
+# disable some checks for tests
+[tool.flakehell.exceptions."tests/"]
+pycodestyle = ["-F401"]     # disable a check
+pyflakes = ["-*"]           # disable a plugin
+
+# do not disable `pyflakes` for one file in tests
+[tool.flakehell.exceptions."tests/test_example.py"]
+pyflakes = ["+*"]           # enable a plugin
 ```
 
 See [Flake8 documentation](http://flake8.pycqa.org/en/latest/user/configuration.html) to read more about Flake8-specific configuration.

flakehell/_logic/__init__.py

@@ -3,7 +3,7 @@
 from ._config import read_config
 from ._discover import get_installed
 from ._extractors import extract
-from ._plugin import get_plugin_name, get_plugin_rules, check_include
+from ._plugin import get_plugin_name, get_plugin_rules, check_include, get_exceptions
 from ._snapshot import Snapshot, prepare_cache
 
 
@@ -13,6 +13,6 @@
     'color_code', 'color_description',
     'get_installed',
     'extract',
-    'get_plugin_name', 'get_plugin_rules', 'check_include',
+    'get_plugin_name', 'get_plugin_rules', 'check_include', 'get_exceptions',
     'Snapshot', 'prepare_cache',
 ]

flakehell/_logic/_config.py

@@ -20,34 +20,37 @@ def read_config(*paths) -> Dict[str, Any]:
     return config
 
 
-def _read_local(path: Path):
+def _read_local(path: Path) -> Dict[str, Any]:
     with path.open('r') as stream:
         return _parse_config(stream.read())
 
 
-def _read_remote(url: str):
+def _read_remote(url: str) -> Dict[str, Any]:
     http = urllib3.PoolManager()
     response = http.request('GET', url)
     return _parse_config(response.data.decode())
 
 
-def _merge_configs(*configs):
+def _merge_configs(*configs) -> Dict[str, Any]:
     config = dict()
     for subconfig in configs:
         config.update(subconfig)
 
-    config['plugins'] = dict()
-    for subconfig in configs:
-        config['plugins'].update(subconfig.get('plugins', {}))
+    for section in ('plugins', 'exceptions'):
+        config[section] = dict()
+        for subconfig in configs:
+            config[section].update(subconfig.get(section, {}))
 
     return config
 
 
-def _parse_config(content: str):
+def _parse_config(content: str) -> Dict[str, Any]:
     config = toml.loads(content).get('tool', {}).get('flakehell', {})
     config = dict(config)
-    if 'plugins' in config:
-        config['plugins'] = dict(config['plugins'])
+
+    for section in ('plugins', 'exceptions'):
+        if section in config:
+            config[section] = dict(config[section])
 
     if 'base' in config:
         paths = config['base']

flakehell/_logic/_plugin.py

@@ -1,5 +1,6 @@
 import re
-from typing import Dict, Any, List
+from pathlib import Path
+from typing import Dict, Any, List, Union
 
 from flake8.utils import fnmatch
 
@@ -11,6 +12,7 @@
     'naming': 'pep8-naming',
     'logging-format': 'flake8-logging-format',
 }
+PluginsType = Dict[str, List[str]]
 
 
 def get_plugin_name(plugin: Dict[str, Any]) -> str:
@@ -41,7 +43,7 @@ def get_plugin_name(plugin: Dict[str, Any]) -> str:
     return names[0]
 
 
-def get_plugin_rules(plugin_name: str, plugins: Dict[str, List[str]]) -> List[str]:
+def get_plugin_rules(plugin_name: str, plugins: PluginsType) -> List[str]:
     """Get rules for plugin from `plugins` in the config
 
     Plugin name can be specified as a glob expression.
@@ -94,3 +96,23 @@ def check_include(code: str, rules: List[str]) -> bool:
         if fnmatch(code, patterns=[rule[1:]]):
             include = rule[0] == '+'
     return include
+
+
+def get_exceptions(
+    path: Union[str, Path], exceptions: Dict[str, PluginsType], root: Path = None,
+) -> PluginsType:
+    if isinstance(path, str):
+        path = Path(path)
+    if root is None:
+        root = Path().resolve()
+    path = path.resolve().relative_to(root).as_posix()
+    exceptions = sorted(
+        exceptions.items(),
+        key=lambda item: len(item[0]),
+        reverse=True,
+    )
+    for path_rule, rules in exceptions:
+        if path.startswith(path_rule):
+            return rules
+
+    return dict()

flakehell/_patched/_app.py

@@ -1,5 +1,6 @@
 import sys
 from argparse import ArgumentParser
+from itertools import chain
 from pathlib import Path
 from typing import Dict, Any, List, Optional, Tuple
 
@@ -27,7 +28,8 @@ def get_toml_config(self, path: Path = None) -> Dict[str, Any]:
         if path is not None:
             return read_config(path)
         # lookup for config from current dir up to root
-        for dir_path in Path('lol').parents:
+        root = Path().resolve()
+        for dir_path in chain([root], root.parents):
             path = dir_path / 'pyproject.toml'
             if path.exists():
                 return read_config(path)

flakehell/_patched/_checkers.py

@@ -1,11 +1,11 @@
-from typing import List, Tuple, Optional
+from typing import Any, Dict, List, Tuple, Optional
 
 from flake8.checker import Manager, FileChecker
 from flake8.utils import fnmatch, filenames_from
 
 from .._logic import (
     get_plugin_name, get_plugin_rules, check_include, make_baseline,
-    Snapshot, prepare_cache,
+    Snapshot, prepare_cache, get_exceptions,
 )
 
 
@@ -62,12 +62,8 @@ def make_checkers(self, paths: List[str] = None) -> None:
     def _make_checker(self, argument, filename, check_type,
                       check) -> Optional['FlakeHellFileChecker']:
         # do not run plugins without rules specified
-        plugin_name = get_plugin_name(check)
-        rules = get_plugin_rules(
-            plugin_name=plugin_name,
-            plugins=self.options.plugins,
-        )
-        if not rules or rules == ['-*']:
+        rules = self._get_rules(check=check, filename=filename)
+        if not rules or set(rules) == {'-*'}:
             return None
 
         if not self._should_create_file_checker(filename=filename, argument=argument):
@@ -84,6 +80,24 @@ def _make_checker(self, argument, filename, check_type,
         #     return None
         return checker
 
+    def _get_rules(self, check: Dict[str, Any], filename: str):
+        plugin_name = get_plugin_name(check)
+        rules = get_plugin_rules(
+            plugin_name=plugin_name,
+            plugins=self.options.plugins,
+        )
+        exceptions = get_exceptions(
+            path=filename,
+            exceptions=self.options.exceptions,
+        )
+        if exceptions:
+            rules = rules.copy()
+            rules += get_plugin_rules(
+                plugin_name=plugin_name,
+                plugins=exceptions,
+            )
+        return rules
+
     def _should_create_file_checker(self, filename: str, argument) -> bool:
         """Filter out excluded files
         """
@@ -133,10 +147,7 @@ def report(self) -> Tuple[int, int]:
 
     def _handle_results(self, filename: str, results: list, check: dict) -> int:
         plugin_name = get_plugin_name(check)
-        rules = get_plugin_rules(
-            plugin_name=plugin_name,
-            plugins=self.options.plugins,
-        )
+        rules = self._get_rules(check=check, filename=filename)
         reported_results_count = 0
         for (error_code, line_number, column, text, physical_line) in results:
             if self.baseline:

flakehell/commands/_lint.py

@@ -11,4 +11,4 @@ def lint_command(argv) -> CommandResult:
         app.run(argv)
         app.exit()
     except SystemExit as exc:
-        return exc.code, ''
+        return int(exc.code), ''

tests/test_cli.py

@@ -1,10 +1,26 @@
 import subprocess
+import os
 import sys
+from contextlib import contextmanager
+from pathlib import Path
+from textwrap import dedent
 
 import pytest
 from flakehell._cli import main
 
 
+@contextmanager
+def chdir(path):
+    """Context manager for changing dir and restoring previous workdir after exit.
+    """
+    curdir = os.getcwd()
+    os.chdir(str(path))
+    try:
+        yield
+    finally:
+        os.chdir(curdir)
+
+
 def test_flake8helled_file():
     """Baseline behavior, when an actual filename is passed."""
     cmd = [
@@ -57,3 +73,28 @@ def test_lint_help(capsys):
     assert '-h, --help' in captured.out
     assert '--builtins' in captured.out
     assert '--isort-show-traceback' in captured.out
+
+
+def test_exclude(capsys, tmp_path: Path):
+    text = """
+    [tool.flakehell.plugins]
+    pyflakes = ["+*"]
+
+    [tool.flakehell.exceptions."tests/"]
+    pyflakes = ["-F401"]
+    """
+    (tmp_path / 'pyproject.toml').write_text(dedent(text))
+    (tmp_path / 'example.py').write_text('import sys\na')
+    (tmp_path / 'tests').mkdir()
+    (tmp_path / 'tests' / 'test_example.py').write_text('import sys\na')
+    with chdir(tmp_path):
+        result = main(['lint', '--format', 'default'])
+    assert result == (1, '')
+    captured = capsys.readouterr()
+    assert captured.err == ''
+    exp = """
+    ./example.py:1:1: F401 'sys' imported but unused
+    ./example.py:2:1: F821 undefined name 'a'
+    ./tests/test_example.py:2:1: F821 undefined name 'a'
+    """
+    assert captured.out.strip() == dedent(exp).strip()

tests/test_logic/test_plugin.py

@@ -0,0 +1,19 @@
+from pathlib import Path
+from flakehell._logic import get_exceptions
+
+
+def test_get_exceptions(tmp_path: Path):
+    tests_path = tmp_path / 'tests'
+    tests_path.mkdir()
+    test_path = tests_path / 'test_example.py'
+    test_path.touch()
+    source_path = tmp_path / 'example.py'
+    source_path.touch()
+
+    exceptions = {
+        'tests/': {'pyflakes': ['+*']},
+    }
+    result = get_exceptions(path=test_path, exceptions=exceptions, root=tmp_path)
+    assert result == {'pyflakes': ['+*']}
+    result = get_exceptions(path=source_path, exceptions=exceptions, root=tmp_path)
+    assert result == {}