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gh-125355: Rewrite parse_intermixed_args() in argparse (GH-125356)
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* The parser no longer changes temporarily during parsing.
* Default values are not processed twice.
* Required mutually exclusive groups containing positional arguments are
  now supported.
* The missing arguments report now includes the names of all required
  optional and positional arguments.
* Unknown options can be intermixed with positional arguments in
  parse_known_intermixed_args().
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@serhiy-storchaka
serhiy-storchaka authored Oct 22, 2024
1 parent 57e3c59 commit 759a54d
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Showing 3 changed files with 80 additions and 82 deletions.
99 changes: 34 additions & 65 deletions Lib/argparse.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1924,6 +1924,9 @@ def parse_args(self, args=None, namespace=None):
return args

def parse_known_args(self, args=None, namespace=None):
return self._parse_known_args2(args, namespace, intermixed=False)

def _parse_known_args2(self, args, namespace, intermixed):
if args is None:
# args default to the system args
args = _sys.argv[1:]
Expand All @@ -1950,18 +1953,18 @@ def parse_known_args(self, args=None, namespace=None):
# parse the arguments and exit if there are any errors
if self.exit_on_error:
try:
namespace, args = self._parse_known_args(args, namespace)
namespace, args = self._parse_known_args(args, namespace, intermixed)
except ArgumentError as err:
self.error(str(err))
else:
namespace, args = self._parse_known_args(args, namespace)
namespace, args = self._parse_known_args(args, namespace, intermixed)

if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):
args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))
delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)
return namespace, args

def _parse_known_args(self, arg_strings, namespace):
def _parse_known_args(self, arg_strings, namespace, intermixed):
# replace arg strings that are file references
if self.fromfile_prefix_chars is not None:
arg_strings = self._read_args_from_files(arg_strings)
Expand Down Expand Up @@ -2052,6 +2055,7 @@ def consume_optional(start_index):
# if we found no optional action, skip it
if action is None:
extras.append(arg_strings[start_index])
extras_pattern.append('O')
return start_index + 1

# if there is an explicit argument, try to match the
Expand Down Expand Up @@ -2087,6 +2091,7 @@ def consume_optional(start_index):
sep = ''
else:
extras.append(char + explicit_arg)
extras_pattern.append('O')
stop = start_index + 1
break
# if the action expect exactly one argument, we've
Expand Down Expand Up @@ -2165,6 +2170,7 @@ def consume_positionals(start_index):
# consume Positionals and Optionals alternately, until we have
# passed the last option string
extras = []
extras_pattern = []
start_index = 0
if option_string_indices:
max_option_string_index = max(option_string_indices)
Expand All @@ -2178,7 +2184,7 @@ def consume_positionals(start_index):
if next_option_string_index in option_string_indices:
break
next_option_string_index += 1
if start_index != next_option_string_index:
if not intermixed and start_index != next_option_string_index:
positionals_end_index = consume_positionals(start_index)

# only try to parse the next optional if we didn't consume
Expand All @@ -2194,16 +2200,35 @@ def consume_positionals(start_index):
if start_index not in option_string_indices:
strings = arg_strings[start_index:next_option_string_index]
extras.extend(strings)
extras_pattern.extend(arg_strings_pattern[start_index:next_option_string_index])
start_index = next_option_string_index

# consume the next optional and any arguments for it
start_index = consume_optional(start_index)

# consume any positionals following the last Optional
stop_index = consume_positionals(start_index)
if not intermixed:
# consume any positionals following the last Optional
stop_index = consume_positionals(start_index)

# if we didn't consume all the argument strings, there were extras
extras.extend(arg_strings[stop_index:])
# if we didn't consume all the argument strings, there were extras
extras.extend(arg_strings[stop_index:])
else:
extras.extend(arg_strings[start_index:])
extras_pattern.extend(arg_strings_pattern[start_index:])
extras_pattern = ''.join(extras_pattern)
assert len(extras_pattern) == len(extras)
# consume all positionals
arg_strings = [s for s, c in zip(extras, extras_pattern) if c != 'O']
arg_strings_pattern = extras_pattern.replace('O', '')
stop_index = consume_positionals(0)
# leave unknown optionals and non-consumed positionals in extras
for i, c in enumerate(extras_pattern):
if not stop_index:
break
if c != 'O':
stop_index -= 1
extras[i] = None
extras = [s for s in extras if s is not None]

# make sure all required actions were present and also convert
# action defaults which were not given as arguments
Expand Down Expand Up @@ -2469,10 +2494,6 @@ def parse_known_intermixed_args(self, args=None, namespace=None):
# are then parsed. If the parser definition is incompatible with the
# intermixed assumptions (e.g. use of REMAINDER, subparsers) a
# TypeError is raised.
#
# positionals are 'deactivated' by setting nargs and default to
# SUPPRESS. This blocks the addition of that positional to the
# namespace

positionals = self._get_positional_actions()
a = [action for action in positionals
Expand All @@ -2481,59 +2502,7 @@ def parse_known_intermixed_args(self, args=None, namespace=None):
raise TypeError('parse_intermixed_args: positional arg'
' with nargs=%s'%a[0].nargs)

if [action.dest for group in self._mutually_exclusive_groups
for action in group._group_actions if action in positionals]:
raise TypeError('parse_intermixed_args: positional in'
' mutuallyExclusiveGroup')

try:
save_usage = self.usage
try:
if self.usage is None:
# capture the full usage for use in error messages
self.usage = self.format_usage()[7:]
for action in positionals:
# deactivate positionals
action.save_nargs = action.nargs
# action.nargs = 0
action.nargs = SUPPRESS
action.save_default = action.default
action.default = SUPPRESS
namespace, remaining_args = self.parse_known_args(args,
namespace)
for action in positionals:
# remove the empty positional values from namespace
if (hasattr(namespace, action.dest)
and getattr(namespace, action.dest)==[]):
from warnings import warn
warn('Do not expect %s in %s' % (action.dest, namespace))
delattr(namespace, action.dest)
finally:
# restore nargs and usage before exiting
for action in positionals:
action.nargs = action.save_nargs
action.default = action.save_default
optionals = self._get_optional_actions()
try:
# parse positionals. optionals aren't normally required, but
# they could be, so make sure they aren't.
for action in optionals:
action.save_required = action.required
action.required = False
for group in self._mutually_exclusive_groups:
group.save_required = group.required
group.required = False
namespace, extras = self.parse_known_args(remaining_args,
namespace)
finally:
# restore parser values before exiting
for action in optionals:
action.required = action.save_required
for group in self._mutually_exclusive_groups:
group.required = group.save_required
finally:
self.usage = save_usage
return namespace, extras
return self._parse_known_args2(args, namespace, intermixed=True)

# ========================
# Value conversion methods
Expand Down
56 changes: 39 additions & 17 deletions Lib/test/test_argparse.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6412,12 +6412,23 @@ def test_basic(self):
# cannot parse the '1,2,3'
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1]), args)
self.assertEqual(["2", "3"], extras)
args, extras = parser.parse_known_intermixed_args(argv)
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1, 2, 3]), args)
self.assertEqual([], extras)

# unknown optionals go into extras
argv = 'cmd --foo x --error 1 2 --bar y 3'.split()
args, extras = parser.parse_known_intermixed_args(argv)
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1, 2, 3]), args)
self.assertEqual(['--error'], extras)
argv = 'cmd --foo x 1 --error 2 --bar y 3'.split()
args, extras = parser.parse_known_intermixed_args(argv)
# unknown optionals go into extras
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1]), args)
self.assertEqual(['--error', '2', '3'], extras)
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1, 2, 3]), args)
self.assertEqual(['--error'], extras)
argv = 'cmd --foo x 1 2 --error --bar y 3'.split()
args, extras = parser.parse_known_intermixed_args(argv)
self.assertEqual(NS(bar='y', cmd='cmd', foo='x', rest=[1, 2, 3]), args)
self.assertEqual(['--error'], extras)

# restores attributes that were temporarily changed
self.assertIsNone(parser.usage)
Expand All @@ -6436,37 +6447,48 @@ def test_remainder(self):
parser.parse_intermixed_args(argv)
self.assertRegex(str(cm.exception), r'\.\.\.')

def test_exclusive(self):
# mutually exclusive group; intermixed works fine
parser = ErrorRaisingArgumentParser(prog='PROG')
def test_required_exclusive(self):
# required mutually exclusive group; intermixed works fine
parser = argparse.ArgumentParser(prog='PROG', exit_on_error=False)
group = parser.add_mutually_exclusive_group(required=True)
group.add_argument('--foo', action='store_true', help='FOO')
group.add_argument('--spam', help='SPAM')
parser.add_argument('badger', nargs='*', default='X', help='BADGER')
args = parser.parse_intermixed_args('--foo 1 2'.split())
self.assertEqual(NS(badger=['1', '2'], foo=True, spam=None), args)
args = parser.parse_intermixed_args('1 --foo 2'.split())
self.assertEqual(NS(badger=['1', '2'], foo=True, spam=None), args)
self.assertRaises(ArgumentParserError, parser.parse_intermixed_args, '1 2'.split())
self.assertRaisesRegex(argparse.ArgumentError,
'one of the arguments --foo --spam is required',
parser.parse_intermixed_args, '1 2'.split())
self.assertEqual(group.required, True)

def test_exclusive_incompatible(self):
# mutually exclusive group including positional - fail
parser = ErrorRaisingArgumentParser(prog='PROG')
def test_required_exclusive_with_positional(self):
# required mutually exclusive group with positional argument
parser = argparse.ArgumentParser(prog='PROG', exit_on_error=False)
group = parser.add_mutually_exclusive_group(required=True)
group.add_argument('--foo', action='store_true', help='FOO')
group.add_argument('--spam', help='SPAM')
group.add_argument('badger', nargs='*', default='X', help='BADGER')
self.assertRaises(TypeError, parser.parse_intermixed_args, [])
args = parser.parse_intermixed_args(['--foo'])
self.assertEqual(NS(foo=True, spam=None, badger='X'), args)
args = parser.parse_intermixed_args(['a', 'b'])
self.assertEqual(NS(foo=False, spam=None, badger=['a', 'b']), args)
self.assertRaisesRegex(argparse.ArgumentError,
'one of the arguments --foo --spam badger is required',
parser.parse_intermixed_args, [])
self.assertRaisesRegex(argparse.ArgumentError,
'argument badger: not allowed with argument --foo',
parser.parse_intermixed_args, ['--foo', 'a', 'b'])
self.assertRaisesRegex(argparse.ArgumentError,
'argument badger: not allowed with argument --foo',
parser.parse_intermixed_args, ['a', '--foo', 'b'])
self.assertEqual(group.required, True)

def test_invalid_args(self):
parser = ErrorRaisingArgumentParser(prog='PROG')
self.assertRaises(ArgumentParserError, parser.parse_intermixed_args, ['a'])

parser = ErrorRaisingArgumentParser(prog='PROG')
parser.add_argument('--foo', nargs="*")
parser.add_argument('foo')
with self.assertWarns(UserWarning):
parser.parse_intermixed_args(['hello', '--foo'])

class TestIntermixedMessageContentError(TestCase):
# case where Intermixed gives different error message
Expand All @@ -6485,7 +6507,7 @@ def test_missing_argument_name_in_message(self):
with self.assertRaises(ArgumentParserError) as cm:
parser.parse_intermixed_args([])
msg = str(cm.exception)
self.assertNotRegex(msg, 'req_pos')
self.assertRegex(msg, 'req_pos')
self.assertRegex(msg, 'req_opt')

# ==========================
Expand Down
7 changes: 7 additions & 0 deletions Misc/NEWS.d/next/Library/2024-10-22-13-28-00.gh-issue-125355.zssHm_.rst
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
Fix several bugs in :meth:`argparse.ArgumentParser.parse_intermixed_args`.

* The parser no longer changes temporarily during parsing.
* Default values are not processed twice.
* Required mutually exclusive groups containing positional arguments are now supported.
* The missing arguments report now includes the names of all required optional and positional arguments.
* Unknown options can be intermixed with positional arguments in parse_known_intermixed_args().

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