[Python-checkins] cpython: Issue #14910: Add allow_abbrev parameter to argparse.ArgumentParser.

Sat Feb 14 00:40:15 CET 2015

https://hg.python.org/cpython/rev/99302634d756
changeset: 94605:99302634d756
user: Berker Peksag <berker.peksag at gmail.com>
date: Sat Feb 14 01:39:17 2015 +0200
summary:
 Issue #14910: Add allow_abbrev parameter to argparse.ArgumentParser.
Patch by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.
files:
 Doc/library/argparse.rst | 35 ++++++++++++++++++++--
 Doc/whatsnew/3.5.rst | 8 +++++
 Lib/argparse.py | 40 ++++++++++++++------------
 Lib/test/test_argparse.py | 33 ++++++++++++++++++++++
 Misc/NEWS | 3 ++
 5 files changed, 97 insertions(+), 22 deletions(-)

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -135,7 +135,7 @@
 formatter_class=argparse.HelpFormatter, \
 prefix_chars='-', fromfile_prefix_chars=None, \
 argument_default=None, conflict_handler='error', \
- add_help=True)
+ add_help=True, allow_abbrev=True)
 
 Create a new :class:`ArgumentParser` object. All parameters should be passed
 as keyword arguments. Each parameter has its own more detailed description
@@ -169,6 +169,12 @@
 
 * add_help_ - Add a -h/--help option to the parser (default: ``True``)
 
+ * allow_abbrev_ - Allows long options to be abbreviated if the
+ abbreviation is unambiguous. (default: ``True``)
+
+ .. versionchanged:: 3.5
+ *allow_abbrev* parameter was added.
+
 The following sections describe how each of these are used.
 
 
@@ -518,6 +524,26 @@
 >>> parser.parse_args([])
 Namespace()
 
+.. _allow_abbrev:
+
+allow_abbrev
+^^^^^^^^^^^^
+
+Normally, when you pass an argument list to the
+:meth:`~ArgumentParser.parse_args` method of a :class:`ArgumentParser`,
+it :ref:`recognizes abbreviations <prefix-matching>` of long options.
+
+This feature can be disabled by setting ``allow_abbrev`` to ``False``::
+
+ >>> parser = argparse.ArgumentParser(prog='PROG', allow_abbrev=False)
+ >>> parser.add_argument('--foobar', action='store_true')
+ >>> parser.add_argument('--foonley', action='store_false')
+ >>> parser.parse_args([--foon])
+ usage: PROG [-h] [--foobar] [--foonley]
+ PROG: error: unrecognized arguments: --foon
+
+.. versionadded:: 3.5
+
 
 conflict_handler
 ^^^^^^^^^^^^^^^^
@@ -1410,9 +1436,9 @@
 Argument abbreviations (prefix matching)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The :meth:`~ArgumentParser.parse_args` method allows long options to be
-abbreviated to a prefix, if the abbreviation is unambiguous (the prefix matches
-a unique option)::
+The :meth:`~ArgumentParser.parse_args` method :ref:`by default <allow_abbrev>`
+allows long options to be abbreviated to a prefix, if the abbreviation is
+unambiguous (the prefix matches a unique option)::
 
 >>> parser = argparse.ArgumentParser(prog='PROG')
 >>> parser.add_argument('-bacon')
@@ -1426,6 +1452,7 @@
 PROG: error: ambiguous option: -ba could match -badger, -bacon
 
 An error is produced for arguments that could produce more than one options.
+This feature can be disabled by setting :ref:`allow_abbrev` to ``False``.
 
 
 Beyond ``sys.argv``
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -146,6 +146,14 @@
 Improved Modules
 ================
 
+argparse
+--------
+
+* :class:`~argparse.ArgumentParser` now allows to disable
+ :ref:`abbreviated usage <prefix-matching>` of long options by setting
+ :ref:`allow_abbrev` to ``False``.
+ (Contributed by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.)
+
 cgi
 ---
 
diff --git a/Lib/argparse.py b/Lib/argparse.py
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1590,6 +1590,7 @@
 - argument_default -- The default value for all arguments
 - conflict_handler -- String indicating how to handle conflicts
 - add_help -- Add a -h/-help option
+ - allow_abbrev -- Allow long options to be abbreviated unambiguously
 """
 
 def __init__(self,
@@ -1603,7 +1604,8 @@
 fromfile_prefix_chars=None,
 argument_default=None,
 conflict_handler='error',
- add_help=True):
+ add_help=True,
+ allow_abbrev=True):
 
 superinit = super(ArgumentParser, self).__init__
 superinit(description=description,
@@ -1621,6 +1623,7 @@
 self.formatter_class = formatter_class
 self.fromfile_prefix_chars = fromfile_prefix_chars
 self.add_help = add_help
+ self.allow_abbrev = allow_abbrev
 
 add_group = self.add_argument_group
 self._positionals = add_group(_('positional arguments'))
@@ -2098,23 +2101,24 @@
 action = self._option_string_actions[option_string]
 return action, option_string, explicit_arg
 
- # search through all possible prefixes of the option string
- # and all actions in the parser for possible interpretations
- option_tuples = self._get_option_tuples(arg_string)
-
- # if multiple actions match, the option string was ambiguous
- if len(option_tuples) > 1:
- options = ', '.join([option_string
- for action, option_string, explicit_arg in option_tuples])
- args = {'option': arg_string, 'matches': options}
- msg = _('ambiguous option: %(option)s could match %(matches)s')
- self.error(msg % args)
-
- # if exactly one action matched, this segmentation is good,
- # so return the parsed action
- elif len(option_tuples) == 1:
- option_tuple, = option_tuples
- return option_tuple
+ if self.allow_abbrev:
+ # search through all possible prefixes of the option string
+ # and all actions in the parser for possible interpretations
+ option_tuples = self._get_option_tuples(arg_string)
+
+ # if multiple actions match, the option string was ambiguous
+ if len(option_tuples) > 1:
+ options = ', '.join([option_string
+ for action, option_string, explicit_arg in option_tuples])
+ args = {'option': arg_string, 'matches': options}
+ msg = _('ambiguous option: %(option)s could match %(matches)s')
+ self.error(msg % args)
+
+ # if exactly one action matched, this segmentation is good,
+ # so return the parsed action
+ elif len(option_tuples) == 1:
+ option_tuple, = option_tuples
+ return option_tuple
 
 # if it was not found as an option, but it looks like a negative
 # number, it was meant to be positional
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -753,6 +753,39 @@
 ]
 
 
+class TestOptionalsAllowLongAbbreviation(ParserTestCase):
+ """Allow long options to be abbreviated unambiguously"""
+
+ argument_signatures = [
+ Sig('--foo'),
+ Sig('--foobaz'),
+ Sig('--fooble', action='store_true'),
+ ]
+ failures = ['--foob 5', '--foob']
+ successes = [
+ ('', NS(foo=None, foobaz=None, fooble=False)),
+ ('--foo 7', NS(foo='7', foobaz=None, fooble=False)),
+ ('--fooba a', NS(foo=None, foobaz='a', fooble=False)),
+ ('--foobl --foo g', NS(foo='g', foobaz=None, fooble=True)),
+ ]
+
+
+class TestOptionalsDisallowLongAbbreviation(ParserTestCase):
+ """Do not allow abbreviations of long options at all"""
+
+ parser_signature = Sig(allow_abbrev=False)
+ argument_signatures = [
+ Sig('--foo'),
+ Sig('--foodle', action='store_true'),
+ Sig('--foonly'),
+ ]
+ failures = ['-foon 3', '--foon 3', '--food', '--food --foo 2']
+ successes = [
+ ('', NS(foo=None, foodle=False, foonly=None)),
+ ('--foo 3', NS(foo='3', foodle=False, foonly=None)),
+ ('--foonly 7 --foodle --foo 2', NS(foo='2', foodle=True, foonly='7')),
+ ]
+
 # ================
 # Positional tests
 # ================
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,9 @@
 Library
 -------
 
+- Issue #14910: Add allow_abbrev parameter to argparse.ArgumentParser. Patch by
+ Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.
+
 - Issue #21717: tarfile.open() now supports 'x' (exclusive creation) mode.
 
 - Issue #23344: marshal.dumps() is now 20-25% faster on average.
-- 
Repository URL: https://hg.python.org/cpython
