Fix _regexp_paths_csv_validator for already validated values

Author: DanielNoord

ChangeLog

@@ -29,6 +29,11 @@ Release date: TBA
   windows directory delimiter instead of a regular expression escape
   character.
 
+* Fixed a crash with the ``ignore-paths`` option when invoking the option
+  via the command line.
+
+  Closes #5437
+
 ..
   Insert your changelog randomly, it will reduce merge conflicts
   (Ie. not necessarily at the end)

pylint/config/option.py

@@ -5,7 +5,7 @@
 import optparse  # pylint: disable=deprecated-module
 import pathlib
 import re
-from typing import List, Pattern
+from typing import List, Pattern, Union
 
 from pylint import utils
 
@@ -27,7 +27,11 @@ def _regexp_csv_validator(_, name, value):
     return [_regexp_validator(_, name, val) for val in _csv_validator(_, name, value)]
 
 
-def _regexp_paths_csv_validator(_, name: str, value: str) -> List[Pattern[str]]:
+def _regexp_paths_csv_validator(
+    _, name: str, value: Union[str, List[Pattern[str]]]
+) -> List[Pattern[str]]:
+    if isinstance(value, list):
+        return value
     patterns = []
     for val in _csv_validator(_, name, value):
         patterns.append(

tests/test_self.py

@@ -1259,3 +1259,13 @@ def test_enable_all_extensions() -> None:
             exit=False,
         )
         assert sorted(plugins) == sorted(runner.linter._dynamic_plugins)
+
+    @staticmethod
+    def test_regex_paths_csv_validator() -> None:
+        """Test to see if _regexp_paths_csv_validator works.
+        Previously the validator crashed when encountering already validated values.
+        Reported in https://github.com/PyCQA/pylint/issues/5437
+        """
+        with pytest.raises(SystemExit) as ex:
+            Run(["--ignore-paths", "test", join(HERE, "regrtest_data", "empty.py")])
+        assert ex.value.code == 0