Right square bracket argparse metavar

[cortopy]

BPO	25058
Nosy	@ncoghlan, @miss-islington
PRs	[3.7] bpo-11874: fix assertion failure in argparse metavar handling (GH-1826) #7527 [3.6] bpo-11874: fix assertion failure in argparse metavar handling (GH-1826) #7528 [3.7] bpo-11874: fix assertion failure in argparse metavar handling (GH-1826) #7530 [2.7] bpo-11874: fix assertion failure in argparse metavar handling (GH-1826) #7553
Superseder	bpo-11874: argparse assertion failure with brackets in metavars

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2016-01-17.06:32:01.301>
created_at = <Date 2015-09-10.16:30:03.157>
labels = ['type-bug', 'library']
title = 'Right square bracket argparse metavar'
updated_at = <Date 2018-06-09.01:28:05.875>
user = 'https://bugs.python.org/cortopy'

bugs.python.org fields:

activity = <Date 2018-06-09.01:28:05.875>
actor = 'miss-islington'
assignee = 'none'
closed = True
closed_date = <Date 2016-01-17.06:32:01.301>
closer = 'martin.panter'
components = ['Library (Lib)']
creation = <Date 2015-09-10.16:30:03.157>
creator = 'cortopy'
dependencies = []
files = []
hgrepos = []
issue_num = 25058
keywords = []
message_count = 7.0
messages = ['250388', '250389', '250427', '319042', '319051', '319055', '319128']
nosy_count = 4.0
nosy_names = ['ncoghlan', 'paul.j3', 'cortopy', 'miss-islington']
pr_nums = ['7527', '7528', '7530', '7553']
priority = 'normal'
resolution = 'duplicate'
stage = None
status = 'closed'
superseder = '11874'
type = 'behavior'
url = 'https://bugs.python.org/issue25058'
versions = ['Python 3.4']

[cortopy]

When trying to assign the metavar in add_argument() method of argparse module I'm unable to include characters after a right square bracket.

Trying to set something like this:

metavar="[host:database:collection:]field"

would raise an AssertionError, which includes:

File "/usr/lib64/python3.4/argparse.py", line 329, in _format_usage
assert ' '.join(opt_parts) == opt_usage

However, the following is accepted:

metavar="[host:database:collection:]field"

[cortopy]

My apologies for the formatting of the last line. This is my issue corrected:

When trying to assign the metavar in add_argument() method of argparse module I'm unable to include characters after a right square bracket.

Trying to set something like this:

metavar="[host:database:collection:]field"

would raise an AssertionError, which includes:

File "/usr/lib64/python3.4/argparse.py", line 329, in _format_usage
assert ' '.join(opt_parts) == opt_usage

However, the following is accepted:

metavar="[host:database:collection:] field"

[paulj3]

This assertion error caused by brackets (and other 'odd' characters) in the metavar is a known issue.

http://bugs.python.org/issue11874
http://bugs.python.org/issue14046

The formatter that handles line wrapping of the usage line is fragile.

[ncoghlan]

New changeset 66f02aa by Nick Coghlan (wim glenn) in branch 'master':
bpo-11874: fix assertion failure in argparse metavar handling (GH-1826)
66f02aa

[miss-islington]

New changeset 376c272 by Miss Islington (bot) in branch '3.6':
bpo-11874: fix assertion failure in argparse metavar handling (GH-1826)
376c272

[miss-islington]

New changeset 842985f by Miss Islington (bot) in branch '3.7':
bpo-11874: fix assertion failure in argparse metavar handling (GH-1826)
842985f

[miss-islington]

New changeset 4e6bd24 by Miss Islington (bot) in branch '2.7':
bpo-11874: fix assertion failure in argparse metavar handling (GH-1826)
4e6bd24