commit 836f137f7ae0799de937e5281cb1da2bfdb8a69d
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Wed Nov 20 05:48:25 2019 -0800
committer GitHub <noreply@github.com> Wed Nov 20 05:48:25 2019 -0800
tree 6516455abc7bf32a38f034f0899b73ffdc46ef8b
parent daf7a082b20e59a0518cda1500add42c36ab058f

bpo-38821: Fix crash in argparse when using gettext (GH-17192)

(cherry picked from commit be5c79e0338005d675a64ba6e5b137e850d556d1)

Co-authored-by: Federico Bond <federicobond@gmail.com>

Lib/argparse.py

diff --git a/Lib/argparse.py b/Lib/argparse.py
index e590225..fd61bc7 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -2093,10 +2093,11 @@
                 OPTIONAL: _('expected at most one argument'),
                 ONE_OR_MORE: _('expected at least one argument'),
             }
-            default = ngettext('expected %s argument',
+            msg = nargs_errors.get(action.nargs)
+            if msg is None:
+                msg = ngettext('expected %s argument',
                                'expected %s arguments',
                                action.nargs) % action.nargs
-            msg = nargs_errors.get(action.nargs, default)
             raise ArgumentError(action, msg)
 
         # return the number of arguments matched