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fix(cli): defensive subparser routing for argparse bpo-9338 (#10113)

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On some Python versions, argparse fails to route subcommand tokens when
the parent parser has nargs='?' optional arguments (--continue).  The
symptom: 'hermes model' produces 'unrecognized arguments: model' even
though 'model' is a registered subcommand.

Fix: when argv contains a token matching a known subcommand, set
subparsers.required=True to force deterministic routing.  If that fails
(e.g. 'hermes -c model' where 'model' is consumed as the session name
for --continue), fall back to the default optional-subparsers behaviour.

Adds 13 tests covering all key argument combinations.

Reported via user screenshot showing the exact error on an installed
version with the model subcommand listed in usage but rejected at parse
time.
This commit is contained in:
Teknium
2026-04-14 23:13:02 -07:00
committed by GitHub
parent 772cfb6c4e
commit 029938fbed
2 changed files with 179 additions and 1 deletions
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32
hermes_cli/main.py
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@@ -6046,7 +6046,37 @@ Examples:
sys.exit(1)
_processed_argv = _coalesce_session_name_args(sys.argv[1:])
args = parser.parse_args(_processed_argv)
# ── Defensive subparser routing (bpo-9338 workaround) ───────────
# On some Python versions (notably <3.11), argparse fails to route
# subcommand tokens when the parent parser has nargs='?' optional
# arguments (--continue). The symptom: "unrecognized arguments: model"
# even though 'model' is a registered subcommand.
#
# Fix: when argv contains a token matching a known subcommand, set
# subparsers.required=True to force deterministic routing. If that
# fails (e.g. 'hermes -c model' where 'model' is consumed as the
# session name for --continue), fall back to the default behaviour.
import io as _io
_known_cmds = set(subparsers.choices.keys()) if hasattr(subparsers, "choices") else set()
_has_cmd_token = any(t in _known_cmds for t in _processed_argv if not t.startswith("-"))
if _has_cmd_token:
subparsers.required = True
_saved_stderr = sys.stderr
try:
sys.stderr = _io.StringIO()
args = parser.parse_args(_processed_argv)
sys.stderr = _saved_stderr
except SystemExit:
sys.stderr = _saved_stderr
# Subcommand name was consumed as a flag value (e.g. -c model).
# Fall back to optional subparsers so argparse handles it normally.
subparsers.required = False
args = parser.parse_args(_processed_argv)
else:
subparsers.required = False
args = parser.parse_args(_processed_argv)
# Handle --version flag
if args.version: