| msg337709 - (view) |
Author: paul j3 (paul.j3) *  |
Date: 2019-03-12 01:36 |
| Test case: parser = argparse.ArgumentParser() parser.add_argument("-a", action="store_true") args = parser.parse_args("-a=".split()) raises an Index_Error, which is not caught by the argparse error mechanism. This is an unusual case, the coincidence of several user errors - 'store_true' which shouldn't take an argument and a short optional with a bare =. So it's unlikely to occur. Still, argparse shouldn't ever respond to a command line value with an uncaught error. The traceback shows that it occurs during the handling of the explicit_arg in consume_optional. Traceback (most recent call last): File "argparseRaiseIndexError.py", line 5, in args = parser.parse_args("-a=".split()) File "/usr/lib/python3.6/argparse.py", line 1743, in parse_args args, argv = self.parse_known_args(args, namespace) File "/usr/lib/python3.6/argparse.py", line 1775, in parse_known_args namespace, args = self._parse_known_args(args, namespace) File "/usr/lib/python3.6/argparse.py", line 1981, in _parse_known_args start_index = consume_optional(start_index) File "/usr/lib/python3.6/argparse.py", line 1881, in consume_optional option_string = char + explicit_arg[0] IndexError: string index out of range The issue was raised in a Stackoverflow question, where I and the poster explore why it occurs, and possible fixes. https://stackoverflow.com/questions/54662609/python-argparse-indexerror-for-passing-a |
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| msg351031 - (view) |
Author: Hai Shi (shihai1991) * |
Date: 2019-09-02 18:09 |
| I do something such as: p = argparse.ArgumentParser() p.add_argument('-a', action='store_true') p.add_argument('-b', action='store_true') p.parse_args('-ab='.split()) thos code code jump in 1903, and the explicit_arg's value is: 'b=' 1901 action_tuples.append((action, [], option_string)) 1902 char = option_string[0] 1903 option_string = char + explicit_arg[0] IMHO, we should judge this explicit_arg's value before jump this judgment statement. |
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| msg351035 - (view) |
Author: Hai Shi (shihai1991) * |
Date: 2019-09-02 18:28 |
| Adding a judgment of explicit_args in judgment statement in the patch. |
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| msg351047 - (view) |
Author: Raymond Hettinger (rhettinger) *  |
Date: 2019-09-03 01:07 |
| FWIW, raising an uncaught exception isn't what we normally consider a "crash". We typically save that designation for segfaults. Ideally, a good patch/pr will also have tests. Also, given the rarity of the exception, I would be reserved about backporting, keeping it to 3.8 and 3.9. |
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| msg351048 - (view) |
Author: Hai Shi (shihai1991) * |
Date: 2019-09-03 01:13 |
| Thanks, Raymond. This patch not a formal patch, just show what i want to do. if everything agree this behavior, I would add a normal PR. |
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| msg351050 - (view) |
Author: Raymond Hettinger (rhettinger) * |
Date: 2019-09-03 03:52 |
| Why did you switch back to "crash"? |
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| msg351061 - (view) |
Author: Hai Shi (shihai1991) * |
Date: 2019-09-03 05:18 |
| oh, sorry, pls ignore it. I misunderstand your opinion. |
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