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argparse.ArgumentParser.parses_args does not honor exit_on_error=False when given unrecognized arguments #121018
Description
Bug report
Bug description:
As reported in Discourse, even though the documentation on the exit_on_error argument for argparse.ArgumentParser says:
exit_on_error- Determines whether or notArgumentParserexits with error info when an error occurs. (default:True)
The parse_args method would still exit with error info when there are unrecognized arguments:
import argparse
parser = argparse.ArgumentParser(exit_on_error=False)
try:
parser.parse_args('invalid arguments'.split())
except argparse.ArgumentError:
print('ArgumentError caught.')which outputs:
usage: test.py [-h]
test.py: error: unrecognized arguments: invalid arguments
CPython versions tested on:
3.12, CPython main branch
Operating systems tested on:
Linux, Windows
Linked PRs
- gh-121018: ensure ArgumentParser.parse_args with exit_on_error=False raises instead of exiting when given unrecognized arguments #121019
- [3.12] gh-121018: Ensure ArgumentParser.parse_args with exit_on_error=False raises instead of exiting when given unrecognized arguments (GH-121019) #121031
- [3.13] gh-121018: Ensure ArgumentParser.parse_args with exit_on_error=False raises instead of exiting when given unrecognized arguments (GH-121019) #121032
- gh-121018: Fix more cases of exiting in argparse when exit_on_error=False #121056
- [3.13] gh-121018: Fix more cases of exiting in argparse when exit_on_error=False (GH-121056) #121128
- [3.12] gh-121018: Fix more cases of exiting in argparse when exit_on_error=False (GH-121056) #121129
- gh-121018: Fix typo in NEWS entry #121510
- [3.12] gh-121018: Fix typo in NEWS entry (GH-121510) #121516
Activity
gh-121018: Ensure ArgumentParser.parse_args with exit_on_error=False …
pythongh-121018: Ensure ArgumentParser.parse_args with exit_on_error=…
pythongh-121018: Ensure ArgumentParser.parse_args with exit_on_error=…
[3.13] gh-121018: Ensure ArgumentParser.parse_args with exit_on_error…
[3.12] gh-121018: Ensure ArgumentParser.parse_args with exit_on_error…
pythongh-121018: Fix more cases of exiting in argparse when exit_on_e…
serhiy-storchaka commentedon Jun 26, 2024
Actually, this is more complex issue.
error()is called in many other places, and it does not honorexit_on_error=False.In most cases it can be replaced with
raise ArgumentError. It is caught at higher level anderror()is called ifexit_on_erroris true.In some cases ValueError may be more appropriate exception than ArgumentError, but this is another issue.
blhsing commentedon Jun 27, 2024
Ah yes good catch. I think
ArgumentErroris meant to be raised by invalid arguments given by the end user. In cases where the error is caused by an improper setup of a parser or an option from the developer, aValueErrorwould indeed be more appropriate.blhsing commentedon Jun 27, 2024
On second thought, I think it may be cleaner to simply put the
if self.exit_on_error: ... else: raise ArgumentErrorlogics directly in theerrormethod, and callself.erroronly when it is caused by the end user.serhiy-storchaka commentedon Jun 28, 2024
There are already open issues for this bug: #85427 and #103498. It is my fault that I did not recognize duplicates.
Yes, putting the logic directly in the error method could simplify some cases, but we want
exit_on_error=Falseto work even with user-overriddenerrormethod.gh-121018: Fix more cases of exiting in argparse when exit_on_error=F…
blhsing commentedon Jun 28, 2024
Ah you're right. I forgot to search for prior bug reports before filing mine. Sorry.
Good point. Will keep the current approach then. Thanks!
[3.13] pythongh-121018: Fix more cases of exiting in argparse when ex…
[3.12] pythongh-121018: Fix more cases of exiting in argparse when ex…
[3.12] gh-121018: Fix more cases of exiting in argparse when exit_on_…
[3.13] gh-121018: Fix more cases of exiting in argparse when exit_on_…
pythongh-121018: Ensure ArgumentParser.parse_args with exit_on_error=…
pythongh-121018: Fix more cases of exiting in argparse when exit_on_e…
gh-121018: Fix typo in NEWS entry (#121510)
[3.12] gh-121018: Fix typo in NEWS entry (GH-121510) (#121516)
pythongh-121018: Ensure ArgumentParser.parse_args with exit_on_error=…
pythongh-121018: Fix more cases of exiting in argparse when exit_on_e…
pythongh-121018: Fix typo in NEWS entry (python#121510)
pythongh-121018: Ensure ArgumentParser.parse_args with exit_on_error=…
pythongh-121018: Fix more cases of exiting in argparse when exit_on_e…
pythongh-121018: Fix typo in NEWS entry (python#121510)