Catch TypeError when validating rcParams types.

From a `matplotlibrc` point of view, the only input would be strings,
which could raise `ValueError`. But from a code point of view,
_anything_ could be assigned to `rcParams`. This raises a `TypeError`
instead of the validator message.

Author: QuLogic

lib/matplotlib/rcsetup.py

@@ -246,7 +246,7 @@ def validator(s):
             return None
         try:
             return cls(s)
-        except ValueError as e:
+        except (TypeError, ValueError) as e:
             raise ValueError(
                 f'Could not convert {s!r} to {cls.__name__}') from e
 

lib/matplotlib/tests/test_rcparams.py

@@ -254,9 +254,7 @@ def generate_validator_testcases(valid):
                      for _ in ('1.5, 2.5', [1.5, 2.5], [1.5, 2.5],
                                (1.5, 2.5), np.array((1.5, 2.5)))),
          'fail': ((_, ValueError)
-                  for _ in ('aardvark', ('a', 1),
-                            (1, 2, 3)
-                            ))
+                  for _ in ('aardvark', ('a', 1), (1, 2, 3), (None, ), None))
          },
         {'validator': validate_cycler,
          'success': (('cycler("color", "rgb")',