commit c589992e09d0db7cb47d21d5948929e599fdbb94
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Fri Jul 23 06:27:05 2021 -0700
committer GitHub <noreply@github.com> Fri Jul 23 15:27:05 2021 +0200
tree 31f2f9ebecb56245e0a72c5c6dda2319b372c084
parent 21db59fc75b6ebb01bf120a8e5930fe032174f73

bpo-29298: Fix crash with required subparsers without dest (GH-3680) (GH-27303)

(cherry picked from commit 17575f73ce2cb9f3a4eb4cc416c690f9a4e7205c)

Co-authored-by: Anthony Sottile <asottile@umich.edu>

Lib/argparse.py

diff --git a/Lib/argparse.py b/Lib/argparse.py
index 8a12dea..e3a49e7 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -727,6 +727,8 @@ def _get_action_name(argument):
         return argument.metavar
     elif argument.dest not in (None, SUPPRESS):
         return argument.dest
+    elif argument.choices:
+        return '{' + ','.join(argument.choices) + '}'
     else:
         return None