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........
  r83675 | r.david.murray | 2010-08-03 13:56:09 -0400 (Tue, 03 Aug 2010) | 12 lines

  #9444: use first of prefix_chars for help opt instead of raising error

  An argparse option parser created with a prefix_chars that did not
  include a '-' would happily add -h and --help options, and then throw
  an error when it tried to format the help because the - was an invalid
  prefix character.  This patch makes it use the first character of
  prefix_chars as the character for the help options if and only if '-'
  is not one of the valid prefix_chars.

  Fix by Theodore Turocy, unit tests by Catherine Devlin.
........
This commit is contained in:
R. David Murray 2010-08-03 18:14:01 +00:00
parent 0f98128d6e
commit 1cbf78e040
5 changed files with 101 additions and 13 deletions

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@ -203,8 +203,8 @@ argument to :class:`ArgumentParser`.
add_help
^^^^^^^^
By default, ArgumentParser objects add a ``-h/--help`` option which simply
displays the parser's help message. For example, consider a file named
By default, ArgumentParser objects add an option which simply displays
the parser's help message. For example, consider a file named
``myprogram.py`` containing the following code::
import argparse
@ -234,12 +234,27 @@ This can be achieved by passing ``False`` as the ``add_help=`` argument to
optional arguments:
--foo FOO foo help
The help option is typically ``-h/--help``. The exception to this is
if the ``prefix_chars=`` is specified and does not include ``'-'``, in
which case ``-h`` and ``--help`` are not valid options. In
this case, the first character in ``prefix_chars`` is used to prefix
the help options::
>>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='+/')
>>> parser.print_help()
usage: PROG [+h]
optional arguments:
+h, ++help show this help message and exit
prefix_chars
^^^^^^^^^^^^
Most command-line options will use ``'-'`` as the prefix, e.g. ``-f/--foo``.
Parsers that need to support additional prefix characters, e.g. for options
Parsers that need to support different or additional prefix
characters, e.g. for options
like ``+f`` or ``/foo``, may specify them using the ``prefix_chars=`` argument
to the ArgumentParser constructor::

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@ -1563,13 +1563,16 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer):
# add help and version arguments if necessary
# (using explicit default to override global argument_default)
default_prefix = '-' if '-' in prefix_chars else prefix_chars[0]
if self.add_help:
self.add_argument(
'-h', '--help', action='help', default=SUPPRESS,
default_prefix+'h', default_prefix*2+'help',
action='help', default=SUPPRESS,
help=_('show this help message and exit'))
if self.version:
self.add_argument(
'-v', '--version', action='version', default=SUPPRESS,
default_prefix+'v', default_prefix*2+'version',
action='version', default=SUPPRESS,
version=self.version,
help=_("show program's version number and exit"))

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@ -420,7 +420,7 @@ class TestOptionalsSingleDoubleDash(ParserTestCase):
class TestOptionalsAlternatePrefixChars(ParserTestCase):
"""Test an Optional with a double-dash option string"""
"""Test an Optional with option strings with custom prefixes"""
parser_signature = Sig(prefix_chars='+:/', add_help=False)
argument_signatures = [
@ -428,6 +428,28 @@ class TestOptionalsAlternatePrefixChars(ParserTestCase):
Sig('::bar'),
Sig('/baz', action='store_const', const=42),
]
failures = ['--bar', '-fbar', '-b B', 'B', '-f', '--bar B', '-baz', '-h', '--help', '+h', '::help', '/help']
successes = [
('', NS(f=False, bar=None, baz=None)),
('+f', NS(f=True, bar=None, baz=None)),
('::ba B', NS(f=False, bar='B', baz=None)),
('+f ::bar B', NS(f=True, bar='B', baz=None)),
('+f /b', NS(f=True, bar=None, baz=42)),
('/ba +f', NS(f=True, bar=None, baz=42)),
]
class TestOptionalsAlternatePrefixCharsAddedHelp(ParserTestCase):
"""When ``-`` not in prefix_chars, default operators created for help
should use the prefix_chars in use rather than - or --
http://bugs.python.org/issue9444"""
parser_signature = Sig(prefix_chars='+:/', add_help=True)
argument_signatures = [
Sig('+f', action='store_true'),
Sig('::bar'),
Sig('/baz', action='store_const', const=42),
]
failures = ['--bar', '-fbar', '-b B', 'B', '-f', '--bar B', '-baz']
successes = [
('', NS(f=False, bar=None, baz=None)),
@ -435,10 +457,9 @@ class TestOptionalsAlternatePrefixChars(ParserTestCase):
('::ba B', NS(f=False, bar='B', baz=None)),
('+f ::bar B', NS(f=True, bar='B', baz=None)),
('+f /b', NS(f=True, bar=None, baz=42)),
('/ba +f', NS(f=True, bar=None, baz=42)),
('/ba +f', NS(f=True, bar=None, baz=42))
]
class TestOptionalsShortLong(ParserTestCase):
"""Test a combination of single- and double-dash option strings"""
@ -1666,12 +1687,18 @@ class TestAddSubparsers(TestCase):
def assertArgumentParserError(self, *args, **kwargs):
self.assertRaises(ArgumentParserError, *args, **kwargs)
def _get_parser(self, subparser_help=False):
def _get_parser(self, subparser_help=False, prefix_chars=None):
# create a parser with a subparsers argument
parser = ErrorRaisingArgumentParser(
prog='PROG', description='main description')
parser.add_argument(
'--foo', action='store_true', help='foo help')
if prefix_chars:
parser = ErrorRaisingArgumentParser(
prog='PROG', description='main description', prefix_chars=prefix_chars)
parser.add_argument(
prefix_chars[0] * 2 + 'foo', action='store_true', help='foo help')
else:
parser = ErrorRaisingArgumentParser(
prog='PROG', description='main description')
parser.add_argument(
'--foo', action='store_true', help='foo help')
parser.add_argument(
'bar', type=float, help='bar help')
@ -1750,6 +1777,44 @@ class TestAddSubparsers(TestCase):
--foo foo help
'''))
def test_help_extra_prefix_chars(self):
# Make sure - is still used for help if it is a non-first prefix char
parser = self._get_parser(prefix_chars='+:-')
self.assertEqual(parser.format_usage(),
'usage: PROG [-h] [++foo] bar {1,2} ...\n')
self.assertEqual(parser.format_help(), textwrap.dedent('''\
usage: PROG [-h] [++foo] bar {1,2} ...
main description
positional arguments:
bar bar help
{1,2} command help
optional arguments:
-h, --help show this help message and exit
++foo foo help
'''))
def test_help_alternate_prefix_chars(self):
parser = self._get_parser(prefix_chars='+:/')
self.assertEqual(parser.format_usage(),
'usage: PROG [+h] [++foo] bar {1,2} ...\n')
self.assertEqual(parser.format_help(), textwrap.dedent('''\
usage: PROG [+h] [++foo] bar {1,2} ...
main description
positional arguments:
bar bar help
{1,2} command help
optional arguments:
+h, ++help show this help message and exit
++foo foo help
'''))
def test_parser_command_help(self):
self.assertEqual(self.command_help_parser.format_usage(),
'usage: PROG [-h] [--foo] bar {1,2} ...\n')

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@ -782,6 +782,7 @@ John Tromp
Jason Trowbridge
Anthony Tuininga
Stephen Turner
Theodore Turocy
Bill Tutt
Doobee R. Tzeck
Eren Türkay

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@ -24,6 +24,10 @@ Core and Builtins
Library
-------
- Issue #9444: Argparse now uses the first element of prefix_chars as
the option character for the added 'h/help' option if prefix_chars
does not contain a '-', instead of raising an error.
- Issue #9354: Provide getsockopt() in asyncore's file_wrapper.
- Issue #7781: Fix restricting stats by entry counts in the pstats