argparse: help parameter not documented in add_subparsers().add_parser

[NazimeKoussailaLakehal]

BPO	39935
Nosy	@rhettinger, @rahul-kumi

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

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-03-11.16:25:58.045>
labels = ['3.8', 'type-feature', '3.7', '3.9', 'docs']
title = 'argparse: help parameter not documented in add_subparsers().add_parser'
updated_at = <Date 2020-03-11.19:07:12.784>
user = 'https://bugs.python.org/NazimeKoussailaLakehal'

bugs.python.org fields:

activity = <Date 2020-03-11.19:07:12.784>
actor = 'rahul-kumi'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2020-03-11.16:25:58.045>
creator = 'Nazime Koussaila Lakehal'
dependencies = []
files = []
hgrepos = []
issue_num = 39935
keywords = []
message_count = 1.0
messages = ['363932']
nosy_count = 5.0
nosy_names = ['rhettinger', 'docs@python', 'paul.j3', 'rahul-kumi', 'Nazime Koussaila Lakehal']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue39935'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

Linked PRs

• gh-84116: Docs: Document help and aliases for argparse.add_parser() #140574
• gh-84116: Add missing backslash to _SubParsersAction.add_parser signature #144572

[NazimeKoussailaLakehal]

The parameter help in the method add_parser of _SubParsersAction (that we obtain with ArgumentParser.add_subparsers()) Is not documented.

In the documentation we can find:
The add_subparsers() method is normally called with no arguments and returns a special action object. This object has a single method, add_parser(), which takes a command name and any ArgumentParser constructor arguments, and returns an ArgumentParser object that can be modified as usual.

I found the parameter by accident and then I checked in the source code, it's unfortunate because the help parameter give really nice output when having sub commands.

the parameter 'aliases' is also not documented.

[slateny]

A few paragraphs into the add_subparsers() section, it says:

(A help message for each subparser command, however, can be given by supplying the help= argument to add_parser() as above.)

Then a few paragraphs further in, it says:

Furthermore, add_parser supports an additional aliases argument, which allows multiple strings to refer to the same subparser.

So it seems that it's technically documented, but just not as well structured as say add_subparsers()