Don't fall back to ~/.netrc if the NETRC env var specified doesn't exist, thus allowing you to disable netrc by setting a non-existent path

Author: pelson

simple_repository_server/__main__.py

@@ -32,20 +32,23 @@ def is_url(url: str) -> bool:
 
 def get_netrc_path() -> typing.Optional[Path]:
     """
-    Get the netrc file path if it exists.
+    Get the netrc file path if it exists and is a regular file.
     Checks NETRC environment variable first, then ~/.netrc.
-    Returns None if no netrc file is found.
+    Returns None if no valid netrc file is found.
+
+    If NETRC is explicitly set but points to a non-existent or invalid file,
+    returns None.
     """
-    # Check if NETRC environment variable is set
     netrc_env = os.environ.get('NETRC')
     if netrc_env:
         netrc_path = Path(netrc_env)
-        if netrc_path.exists():
+        if netrc_path.exists() and netrc_path.is_file():
             return netrc_path
+        # If NETRC is explicitly set but invalid, don't fall back to ~/.netrc
+        return None
 
-    # Check for default ~/.netrc file
     default_netrc = Path.home() / '.netrc'
-    if default_netrc.exists():
+    if default_netrc.exists() and default_netrc.is_file():
         return default_netrc
 
     return None

simple_repository_server/tests/test_netrc_auth.py

@@ -46,12 +46,26 @@ def test_get_netrc__path_in_home(tmp_home: Path, netrc_file: Path):
 
 
 def test_get_netrc__netrc_env_var(netrc_file: Path, monkeypatch: pytest.MonkeyPatch):
-    """Test get_netrc_path returns None when no netrc file exists."""
+    """Test get_netrc_path uses NETRC environment variable when file exists."""
     monkeypatch.setenv('NETRC', str(netrc_file))
     result = get_netrc_path()
     assert result == netrc_file
 
 
+def test_get_netrc__netrc_env_var_nonexistent(tmp_home: Path, netrc_file: Path, monkeypatch: pytest.MonkeyPatch):
+    """Test get_netrc_path returns None when NETRC points to non-existent file (no fallback)."""
+    # Create ~/.netrc in home directory
+    home_netrc = tmp_home / '.netrc'
+    netrc_file.rename(home_netrc)
+
+    # Set NETRC to non-existent file
+    monkeypatch.setenv('NETRC', str(tmp_home / 'doesnt_exist'))
+    result = get_netrc_path()
+
+    # Should return None, NOT fall back to ~/.netrc
+    assert result is None
+
+
 def test_create_app__with_netrc(netrc_file: Path, monkeypatch: pytest.MonkeyPatch):
     monkeypatch.setenv('NETRC', str(netrc_file))
     with mock.patch(