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cykerwayserhiy-storchaka
cykerway
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serhiy-storchaka
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gh-58282: Fix support of tuple metavar for positional arguments in argparse
Previously, formatting help output or error message for positional argument with a tuple metavar raised exception. Co-authored-b: Cyker Way <cykerway@gmail.com>
1 parent 95581b3 commit b24aa03

3 files changed

Lines changed: 109 additions & 4 deletions

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‎Lib/argparse.py‎

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -527,8 +527,7 @@ def _format_action(self, action):
527527
def _format_action_invocation(self, action):
528528
if not action.option_strings:
529529
default = self._get_default_metavar_for_positional(action)
530-
metavar, = self._metavar_formatter(action, default)(1)
531-
return metavar
530+
return ' '.join(self._metavar_formatter(action, default)(1))
532531

533532
else:
534533

@@ -703,7 +702,15 @@ def _get_action_name(argument):
703702
elif argument.option_strings:
704703
return '/'.join(argument.option_strings)
705704
elif argument.metavar not in (None, SUPPRESS):
706-
return argument.metavar
705+
metavar = argument.metavar
706+
if not isinstance(metavar, tuple):
707+
return metavar
708+
if argument.nargs == ZERO_OR_MORE and len(metavar) == 2:
709+
return '%s[, %s]' % metavar
710+
elif argument.nargs == ONE_OR_MORE:
711+
return '%s[, %s]' % metavar
712+
else:
713+
return ', '.join(metavar)
707714
elif argument.dest not in (None, SUPPRESS):
708715
return argument.dest
709716
elif argument.choices:

‎Lib/test/test_argparse.py‎

Lines changed: 97 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4895,7 +4895,7 @@ class TestHelpNone(HelpTestCase):
48954895
version = ''
48964896

48974897

4898-
class TestHelpTupleMetavar(HelpTestCase):
4898+
class TestHelpTupleMetavarOptional(HelpTestCase):
48994899
"""Test specifying metavar as a tuple"""
49004900

49014901
parser_signature = Sig(prog='PROG')
@@ -4922,6 +4922,34 @@ class TestHelpTupleMetavar(HelpTestCase):
49224922
version = ''
49234923

49244924

4925+
class TestHelpTupleMetavarPositional(HelpTestCase):
4926+
"""Test specifying metavar on a Positional as a tuple"""
4927+
4928+
parser_signature = Sig(prog='PROG')
4929+
argument_signatures = [
4930+
Sig('w', help='w help', nargs='+', metavar=('W1', 'W2')),
4931+
Sig('x', help='x help', nargs='*', metavar=('X1', 'X2')),
4932+
Sig('y', help='y help', nargs=3, metavar=('Y1', 'Y2', 'Y3')),
4933+
Sig('z', help='z help', nargs='?', metavar=('Z1',)),
4934+
]
4935+
argument_group_signatures = []
4936+
usage = '''\
4937+
usage: PROG [-h] W1 [W2 ...] [X1 [X2 ...]] Y1 Y2 Y3 [Z1]
4938+
'''
4939+
help = usage + '''\
4940+
4941+
positional arguments:
4942+
W1 W2 w help
4943+
X1 X2 x help
4944+
Y1 Y2 Y3 y help
4945+
Z1 z help
4946+
4947+
options:
4948+
-h, --help show this help message and exit
4949+
'''
4950+
version = ''
4951+
4952+
49254953
class TestHelpRawText(HelpTestCase):
49264954
"""Test the RawTextHelpFormatter"""
49274955

@@ -6518,6 +6546,27 @@ def test_required_args(self):
65186546
'the following arguments are required: bar, baz$',
65196547
self.parser.parse_args, [])
65206548

6549+
def test_required_args_with_metavar(self):
6550+
self.parser.add_argument('bar')
6551+
self.parser.add_argument('baz', metavar='BaZ')
6552+
self.assertRaisesRegex(argparse.ArgumentError,
6553+
'the following arguments are required: bar, BaZ$',
6554+
self.parser.parse_args, [])
6555+
6556+
def test_required_args_n(self):
6557+
self.parser.add_argument('bar')
6558+
self.parser.add_argument('baz', nargs=3)
6559+
self.assertRaisesRegex(argparse.ArgumentError,
6560+
'the following arguments are required: bar, baz$',
6561+
self.parser.parse_args, [])
6562+
6563+
def test_required_args_n_with_metavar(self):
6564+
self.parser.add_argument('bar')
6565+
self.parser.add_argument('baz', nargs=3, metavar=('B', 'A', 'Z'))
6566+
self.assertRaisesRegex(argparse.ArgumentError,
6567+
'the following arguments are required: bar, B, A, Z$',
6568+
self.parser.parse_args, [])
6569+
65216570
def test_required_args_optional(self):
65226571
self.parser.add_argument('bar')
65236572
self.parser.add_argument('baz', nargs='?')
@@ -6532,6 +6581,20 @@ def test_required_args_zero_or_more(self):
65326581
'the following arguments are required: bar$',
65336582
self.parser.parse_args, [])
65346583

6584+
def test_required_args_one_or_more(self):
6585+
self.parser.add_argument('bar')
6586+
self.parser.add_argument('baz', nargs='+')
6587+
self.assertRaisesRegex(argparse.ArgumentError,
6588+
'the following arguments are required: bar, baz$',
6589+
self.parser.parse_args, [])
6590+
6591+
def test_required_args_one_or_more_with_metavar(self):
6592+
self.parser.add_argument('bar')
6593+
self.parser.add_argument('baz', nargs='+', metavar=('BaZ1', 'BaZ2'))
6594+
self.assertRaisesRegex(argparse.ArgumentError,
6595+
r'the following arguments are required: bar, BaZ1\[, BaZ2]$',
6596+
self.parser.parse_args, [])
6597+
65356598
def test_required_args_remainder(self):
65366599
self.parser.add_argument('bar')
65376600
self.parser.add_argument('baz', nargs='...')
@@ -6547,6 +6610,39 @@ def test_required_mutually_exclusive_args(self):
65476610
'one of the arguments --bar --baz is required',
65486611
self.parser.parse_args, [])
65496612

6613+
def test_conflicting_mutually_exclusive_args_optional_with_metavar(self):
6614+
group = self.parser.add_mutually_exclusive_group()
6615+
group.add_argument('--bar')
6616+
group.add_argument('baz', nargs='?', metavar='BaZ')
6617+
self.assertRaisesRegex(argparse.ArgumentError,
6618+
'argument BaZ: not allowed with argument --bar$',
6619+
self.parser.parse_args, ['--bar', 'a', 'b'])
6620+
self.assertRaisesRegex(argparse.ArgumentError,
6621+
'argument --bar: not allowed with argument BaZ$',
6622+
self.parser.parse_args, ['a', '--bar', 'b'])
6623+
6624+
def test_conflicting_mutually_exclusive_args_zero_or_more_with_metavar1(self):
6625+
group = self.parser.add_mutually_exclusive_group()
6626+
group.add_argument('--bar')
6627+
group.add_argument('baz', nargs='*', metavar=('BAZ1',))
6628+
self.assertRaisesRegex(argparse.ArgumentError,
6629+
'argument BAZ1: not allowed with argument --bar$',
6630+
self.parser.parse_args, ['--bar', 'a', 'b'])
6631+
self.assertRaisesRegex(argparse.ArgumentError,
6632+
'argument --bar: not allowed with argument BAZ1$',
6633+
self.parser.parse_args, ['a', '--bar', 'b'])
6634+
6635+
def test_conflicting_mutually_exclusive_args_zero_or_more_with_metavar2(self):
6636+
group = self.parser.add_mutually_exclusive_group()
6637+
group.add_argument('--bar')
6638+
group.add_argument('baz', nargs='*', metavar=('BAZ1', 'BAZ2'))
6639+
self.assertRaisesRegex(argparse.ArgumentError,
6640+
r'argument BAZ1\[, BAZ2]: not allowed with argument --bar$',
6641+
self.parser.parse_args, ['--bar', 'a', 'b'])
6642+
self.assertRaisesRegex(argparse.ArgumentError,
6643+
r'argument --bar: not allowed with argument BAZ1\[, BAZ2]$',
6644+
self.parser.parse_args, ['a', '--bar', 'b'])
6645+
65506646
def test_ambiguous_option(self):
65516647
self.parser.add_argument('--foobaz')
65526648
self.parser.add_argument('--fooble', action='store_true')

‎Misc/NEWS.d/next/Library/2018-12-04-07-36-27.bpo-14074.fMLKCu.rst‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,2 @@
1+
Fix :mod:`argparse` metavar processing to allow positional arguments to have a
2+
tuple metavar.

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