Keep the original input during _check_value

This will allow better error messages.

Author: hansthen

Lib/argparse.py

@@ -2528,7 +2528,7 @@ def _get_values(self, action, arg_strings):
         elif len(arg_strings) == 1 and action.nargs in [None, OPTIONAL]:
             arg_string, = arg_strings
             value = self._get_value(action, arg_string)
-            self._check_value(action, value)
+            self._check_value(action, value, arg_string)
 
         # REMAINDER arguments convert all values, checking none
         elif action.nargs == REMAINDER:
@@ -2537,7 +2537,7 @@ def _get_values(self, action, arg_strings):
         # PARSER arguments convert all values, but check only the first
         elif action.nargs == PARSER:
             value = [self._get_value(action, v) for v in arg_strings]
-            self._check_value(action, value[0])
+            self._check_value(action, value[0], arg_strings[0])
 
         # SUPPRESS argument does not put anything in the namespace
         elif action.nargs == SUPPRESS:
@@ -2546,8 +2546,8 @@ def _get_values(self, action, arg_strings):
         # all other types of nargs produce a list
         else:
             value = [self._get_value(action, v) for v in arg_strings]
-            for v in value:
-                self._check_value(action, v)
+            for v, s in zip(value, arg_strings):
+                self._check_value(action, v, s)
 
         # return the converted value
         return value
@@ -2576,34 +2576,38 @@ def _get_value(self, action, arg_string):
         # return the converted value
         return result
 
-    def _check_value(self, action, value):
+    def _check_value(self, action, value, arg_string=None):
         # converted value must be one of the choices (if specified)
         choices = action.choices
         if choices is None:
             return
 
+        if arg_string is None:
+            arg_string = value
+
         if isinstance(choices, str):
             choices = iter(choices)
 
         typed_choices = []
         if (self.convert_choices and
-            self.type and
-            isinstance(self.choices[0], str)):
+            action.type and
+            all(isinstance(choice, str) for choice in choices)
+        ):
             try:
-                typed_choices = [acton.type[v] for v in choices]
+                typed_choices = [action.type(v) for v in choices]
             except Exception:
                 # We use a blanket catch here, because type is user provided.
                 pass
 
         if value not in choices and value not in typed_choices:
-            args = {'value': str(value),
+            args = {'value': arg_string,
                     'choices': ', '.join(map(str, action.choices))}
             msg = _('invalid choice: %(value)r (choose from %(choices)s)')
 
-            if self.suggest_on_error and isinstance(value, str):
+            if self.suggest_on_error:
                 if all(isinstance(choice, str) for choice in action.choices):
                     import difflib
-                    suggestions = difflib.get_close_matches(value, action.choices, 1)
+                    suggestions = difflib.get_close_matches(arg_string, action.choices, 1)
                     if suggestions:
                         args['closest'] = suggestions[0]
                         msg = _('invalid choice: %(value)r, maybe you meant %(closest)r? '