ignore config files in the home directory

src/flake8/options/config.py

@@ -14,7 +14,18 @@ from flake8.options.manager import OptionManager
 LOG = logging.getLogger(__name__)
 
 
+def _stat_key(s: str) -> Tuple[int, int]:
+    # same as what's used by samefile / samestat
+    st = os.stat(s)
+    return st.st_ino, st.st_dev
+
+
 def _find_config_file(path: str) -> Optional[str]:
+    # on windows if the homedir isn't detected this returns back `~`
+    home = os.path.expanduser("~")
+    home_stat = _stat_key(home) if home != "~" else None
+
+    dir_stat = _stat_key(path)
     cfg = configparser.RawConfigParser()
     while True:
         for candidate in ("setup.cfg", "tox.ini", ".flake8"):
@@ -29,10 +40,12 @@ def _find_config_file(path: str) -> Optional[str]:
                     return cfg_path
 
         new_path = os.path.dirname(path)
-        if new_path == path:
+        new_dir_stat = _stat_key(new_path)
+        if new_dir_stat == dir_stat or new_dir_stat == home_stat:
             break
         else:
             path = new_path
+            dir_stat = new_dir_stat
 
     # did not find any configuration file
     return None

tests/unit/test_options_config.py

@@ -1,4 +1,6 @@
 import configparser
+import os.path
+from unittest import mock
 
 import pytest
 
@@ -66,6 +68,16 @@ def test_find_config_searches_upwards(tmp_path):
     assert config._find_config_file(str(subdir)) == str(expected)
 
 
+def test_find_config_ignores_homedir(tmp_path):
+    subdir = tmp_path.joinpath("d")
+    subdir.mkdir()
+
+    tmp_path.joinpath(".flake8").write_text("[flake8]")
+
+    with mock.patch.object(os.path, "expanduser", return_value=str(tmp_path)):
+        assert config._find_config_file(str(subdir)) is None
+
+
 def test_load_config_config_specified_skips_discovery(tmpdir):
     tmpdir.join("setup.cfg").write("[flake8]\nindent-size=2\n")
     custom_cfg = tmpdir.join("custom.cfg")