Fixed option callbacks not getting run

1 files changed, 10 insertions, 6 deletions

diff --git a/pylint/config.py b/pylint/config.py
index ae1d87fd1..a446171e8 100644
--- a/pylint/config.py
+++ b/pylint/config.py
@@ -581,16 +581,20 @@ Please report bugs on the project\'s mailing list:
 class OptionsManagerMixIn:
     """Handle configuration from both a configuration file and command line options"""
 
-    class NullAction(argparse.Action):
+    class CallbackAction(argparse.Action):
         """Doesn't store the value on the config."""
 
-        def __init__(self, *args, nargs=0, **kwargs):
-            super(OptionsManagerMixIn.NullAction, self).__init__(
+        def __init__(self, *args, nargs=None, **kwargs):
+            nargs = nargs or int("metavar" in kwargs)
+            super(OptionsManagerMixIn.CallbackAction, self).__init__(
                 *args, nargs=nargs, **kwargs
             )
 
-        def __call__(self, *args, **kwargs):
-            pass
+        def __call__(self, parser, namespace, values, option_string):
+            # If no value was passed, argparse didn't call the callback via
+            # `type`, so we need to do it ourselves.
+            if not self.nargs and callable(self.type):
+                self.type(self, option_string, values, parser)
 
     def __init__(self, usage, config_file=None, version=None):
         self.config_file = config_file
@@ -693,7 +697,7 @@ class OptionsManagerMixIn:
             self._nocallback_options[provider] = opt
             if optdict["action"] == "callback":
                 optdict["type"] = optdict["callback"]
-                optdict["action"] = self.NullAction
+                optdict["action"] = self.CallbackAction
                 del optdict["callback"]
         else:
             callback = functools.partial(