[Python-checkins] [3.8] bpo-39546: argparse: Honor allow_abbrev=False for specified prefix_chars (GH-18337) (GH-18543)
Miss Islington (bot)
webhook-mailer at python.org
Tue Feb 18 06:14:12 EST 2020
https://github.com/python/cpython/commit/e412cbba52e7cf6699720d99a4b88baef92db7b2
commit: e412cbba52e7cf6699720d99a4b88baef92db7b2
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020-02-18T03:14:07-08:00
summary:
[3.8] bpo-39546: argparse: Honor allow_abbrev=False for specified prefix_chars (GH-18337) (GH-18543)
When `allow_abbrev` was first added, disabling the abbreviation of
long options broke the grouping of short flags ([bpo-26967](https://bugs.python.org/issue26967)). As a fix,
b1e4d1b603 (contained in v3.8) ignores `allow_abbrev=False` for a
given argument string if the string does _not_ start with "--"
(i.e. it doesn't look like a long option).
This fix, however, doesn't take into account that long options can
start with alternative characters specified via `prefix_chars`,
introducing a regression: `allow_abbrev=False` has no effect on long
options that start with an alternative prefix character.
The most minimal fix would be to replace the "starts with --" check
with a "starts with two prefix_chars characters". But
`_get_option_tuples` already distinguishes between long and short
options, so let's instead piggyback off of that check by moving the
`allow_abbrev` condition into `_get_option_tuples`.
https://bugs.python.org/issue39546
(cherry picked from commit 8edfc47baec7ff4cb1b9db83dd35c8ffc1d498a4)
Co-authored-by: Kyle Meyer <kyle at kyleam.com>
https://bugs.python.org/issue39546
Automerge-Triggered-By: @encukou
files:
A Misc/NEWS.d/next/Library/2020-02-03-15-12-51.bpo-39546._Kj0Pn.rst
M Lib/argparse.py
M Lib/test/test_argparse.py
M Misc/ACKS
diff --git a/Lib/argparse.py b/Lib/argparse.py
index fd61bc78c2c3d..2dad5f123f390 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -2144,24 +2144,23 @@ def _parse_optional(self, arg_string):
action = self._option_string_actions[option_string]
return action, option_string, explicit_arg
- if self.allow_abbrev or not arg_string.startswith('--'):
- # 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
+ # 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
@@ -2185,16 +2184,17 @@ def _get_option_tuples(self, option_string):
# split at the '='
chars = self.prefix_chars
if option_string[0] in chars and option_string[1] in chars:
- if '=' in option_string:
- option_prefix, explicit_arg = option_string.split('=', 1)
- else:
- option_prefix = option_string
- explicit_arg = None
- for option_string in self._option_string_actions:
- if option_string.startswith(option_prefix):
- action = self._option_string_actions[option_string]
- tup = action, option_string, explicit_arg
- result.append(tup)
+ if self.allow_abbrev:
+ if '=' in option_string:
+ option_prefix, explicit_arg = option_string.split('=', 1)
+ else:
+ option_prefix = option_string
+ explicit_arg = None
+ for option_string in self._option_string_actions:
+ if option_string.startswith(option_prefix):
+ action = self._option_string_actions[option_string]
+ tup = action, option_string, explicit_arg
+ result.append(tup)
# single character options can be concatenated with their arguments
# but multiple character options always have to have their argument
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 86ec6cca51acc..0753a4b59652d 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -786,6 +786,23 @@ class TestOptionalsDisallowLongAbbreviation(ParserTestCase):
]
+class TestOptionalsDisallowLongAbbreviationPrefixChars(ParserTestCase):
+ """Disallowing abbreviations works with alternative prefix characters"""
+
+ parser_signature = Sig(prefix_chars='+', 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')),
+ ]
+
+
class TestDisallowLongAbbreviationAllowsShortGrouping(ParserTestCase):
"""Do not allow abbreviations of long options at all"""
@@ -804,6 +821,26 @@ class TestDisallowLongAbbreviationAllowsShortGrouping(ParserTestCase):
('-ccrcc', NS(r='cc', c=2)),
]
+
+class TestDisallowLongAbbreviationAllowsShortGroupingPrefix(ParserTestCase):
+ """Short option grouping works with custom prefix and allow_abbrev=False"""
+
+ parser_signature = Sig(prefix_chars='+', allow_abbrev=False)
+ argument_signatures = [
+ Sig('+r'),
+ Sig('+c', action='count'),
+ ]
+ failures = ['+r', '+c +r']
+ successes = [
+ ('', NS(r=None, c=None)),
+ ('+ra', NS(r='a', c=None)),
+ ('+rcc', NS(r='cc', c=None)),
+ ('+cc', NS(r=None, c=2)),
+ ('+cc +ra', NS(r='a', c=2)),
+ ('+ccrcc', NS(r='cc', c=2)),
+ ]
+
+
# ================
# Positional tests
# ================
diff --git a/Misc/ACKS b/Misc/ACKS
index 21ee85b4558ed..69ed251b988db 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1096,6 +1096,7 @@ Brian Merrell
Alexis Métaireau
Luke Mewburn
Carl Meyer
+Kyle Meyer
Mike Meyer
Piotr Meyer
Steven Miale
diff --git a/Misc/NEWS.d/next/Library/2020-02-03-15-12-51.bpo-39546._Kj0Pn.rst b/Misc/NEWS.d/next/Library/2020-02-03-15-12-51.bpo-39546._Kj0Pn.rst
new file mode 100644
index 0000000000000..8f035e79963e0
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-02-03-15-12-51.bpo-39546._Kj0Pn.rst
@@ -0,0 +1,3 @@
+Fix a regression in :class:`~argparse.ArgumentParser` where
+``allow_abbrev=False`` was ignored for long options that used a prefix
+character other than "-".
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