Accept a comma-separated list of messages IDs in --help-msg (#7490)

doc/whatsnew/fragments/7471.bugfix

@@ -0,0 +1,3 @@
+``--help-msg`` now accepts a comma-separated list of message IDs again.
+
+Closes #7471

pylint/config/callback_actions.py

@@ -158,7 +158,11 @@ def __call__(
         option_string: str | None = "--help-msg",
     ) -> None:
         assert isinstance(values, (list, tuple))
-        self.run.linter.msgs_store.help_message(values)
+        values_to_print: list[str] = []
+        for msg in values:
+            assert isinstance(msg, str)
+            values_to_print += utils._check_csv(msg)
+        self.run.linter.msgs_store.help_message(values_to_print)
         sys.exit(0)
 
 

tests/test_self.py

@@ -1229,6 +1229,7 @@ def test_output_of_callback_options(
             [["--help-msg", "W0101"], ":unreachable (W0101)", False],
             [["--help-msg", "WX101"], "No such message id", False],
             [["--help-msg"], "--help-msg: expected at least one argumen", True],
+            [["--help-msg", "C0102,C0103"], ":invalid-name (C0103):", False],
         ],
     )
     def test_help_msg(