fix: distinguish stdout or stderr when colorizing output in argparse

Signed-off-by: Frost Ming <me@frostming.com>

Author: frostming

Lib/argparse.py

@@ -89,8 +89,8 @@
 import os as _os
 import re as _re
 import sys as _sys
-
-from gettext import gettext as _, ngettext
+from gettext import gettext as _
+from gettext import ngettext
 
 SUPPRESS = '==SUPPRESS=='
 
@@ -191,10 +191,10 @@ def __init__(
 
         self._set_color(False)
 
-    def _set_color(self, color):
+    def _set_color(self, color, *, file=None):
         from _colorize import can_colorize, decolor, get_theme
 
-        if color and can_colorize():
+        if color and can_colorize(file=file):
             self._theme = get_theme(force_color=True).argparse
             self._decolor = decolor
         else:
@@ -1675,7 +1675,7 @@ def _get_optional_kwargs(self, *args, **kwargs):
         option_strings = []
         for option_string in args:
             # error on strings that don't start with an appropriate prefix
-            if not option_string[0] in self.prefix_chars:
+            if option_string[0] not in self.prefix_chars:
                 raise ValueError(
                     f'invalid option string {option_string!r}: '
                     f'must start with a character {self.prefix_chars!r}')
@@ -2455,7 +2455,7 @@ def _parse_optional(self, arg_string):
             return None
 
         # if it doesn't start with a prefix, it was meant to be positional
-        if not arg_string[0] in self.prefix_chars:
+        if arg_string[0] not in self.prefix_chars:
             return None
 
         # if the option string is present in the parser, return the action
@@ -2717,14 +2717,16 @@ def _check_value(self, action, value):
     # Help-formatting methods
     # =======================
 
-    def format_usage(self):
-        formatter = self._get_formatter()
+    def format_usage(self, formatter=None):
+        if formatter is None:
+            formatter = self._get_formatter()
         formatter.add_usage(self.usage, self._actions,
                             self._mutually_exclusive_groups)
         return formatter.format_help()
 
-    def format_help(self):
-        formatter = self._get_formatter()
+    def format_help(self, formatter=None):
+        if formatter is None:
+            formatter = self._get_formatter()
 
         # usage
         formatter.add_usage(self.usage, self._actions,
@@ -2765,12 +2767,16 @@ def _get_validation_formatter(self):
     def print_usage(self, file=None):
         if file is None:
             file = _sys.stdout
-        self._print_message(self.format_usage(), file)
+        formatter = self._get_formatter()
+        formatter._set_color(self.color, file=file)
+        self._print_message(self.format_usage(formatter=formatter), file)
 
     def print_help(self, file=None):
         if file is None:
             file = _sys.stdout
-        self._print_message(self.format_help(), file)
+        formatter = self._get_formatter()
+        formatter._set_color(self.color, file=file)
+        self._print_message(self.format_help(formatter=formatter), file)
 
     def _print_message(self, message, file=None):
         if message: