Bug report

When ArgumentParser encounters certain errors, it calls self.error(...) which exits, even when exit_on_error is set to False.

This prevents catching the exception and writing a custom error message.

import argparse parser = argparse.ArgumentParser(exit_on_error=False) parser.add_argument('filename') try: args = parser.parse_args([]) except Exception: print("Bad argument, here's what you should do instead...")

Test on Python 3.11.3:

python argparse-bug/repro.py usage: repro.py [-h] filename repro.py: error: the following arguments are required: filename

Linked PRs

• gh-103498: argparse.ArgumentParser will always throw instead of exit if exit_on_error=False #103519