commands: formalise a Choice type

This resolves as a string during MyPy checks, but at runtime has an additional
attribute that is a command that returns valid options.

This is very ugly and clumsy, basically because MyPy is super restrictive about
what it accepts as a type. Almost any attempt to construct these types in a
more sophisticated way fails in one way or another. I'm open to suggestions.

1 files changed, 1 insertions, 1 deletions

diff --git a/mitmproxy/utils/typecheck.py b/mitmproxy/utils/typecheck.py
index 87a0e804..c5e289a4 100644
--- a/mitmproxy/utils/typecheck.py
+++ b/mitmproxy/utils/typecheck.py
@@ -31,7 +31,7 @@ def check_command_type(value: typing.Any, typeinfo: typing.Any) -> bool:
                 return False
     elif value is None and typeinfo is None:
         return True
-    elif not isinstance(value, typeinfo):
+    elif (not isinstance(typeinfo, type)) or (not isinstance(value, typeinfo)):
         return False
     return True