Skip to content

bpo-14856: Deprecate using add_parser() to overwrite an existing subparser #10159

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
bradengroom wants to merge 1 commit into from
Closed

bpo-14856: Deprecate using add_parser() to overwrite an existing subparser #10159

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions Doc/whatsnew/3.8.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -312,6 +312,10 @@ Deprecated

(Contributed by Serhiy Storchaka in :issue:`33710`.)

* Using :meth:`~argparser._SubParsersAction.add_parser` to overwrite an existing
subparser is deprecated and will be prohibited in Python 3.9.
(Contributed by Braden Groom in :issue:`14856`.)


Removed
=======
Expand Down
14 changes: 14 additions & 0 deletions Lib/argparse.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1097,6 +1097,20 @@ def __init__(self,
metavar=metavar)

def add_parser(self, name, **kwargs):
import warnings
if name in self._name_parser_map:
warnings.warn('using add_parser() to overwrite an existing '
'subparser is deprecated, use set_parser() instead',
DeprecationWarning, 2)
aliases = kwargs.get('aliases', [])
for alias in aliases:
if alias in self._name_parser_map:
warnings.warn('using add_parser() to overwrite an existing '
'subparser is deprecated, use set_parser() instead',
DeprecationWarning, 2)
return self.set_parser(name, **kwargs)

def set_parser(self, name, **kwargs):
# set prog from the existing prefix
if kwargs.get('prog') is None:
kwargs['prog'] = '%s %s' % (self._prog_prefix, name)
Expand Down
12 changes: 12 additions & 0 deletions Lib/test/test_argparse.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2149,6 +2149,18 @@ def test_alias_help(self):
3 3 help
"""))

def test_warn_already_defined_subparser(self):
parser = ErrorRaisingArgumentParser()
subparsers = parser.add_subparsers()
subparsers.add_parser('foo')
self.assertWarns(DeprecationWarning, subparsers.add_parser, 'foo')

def test_warn_already_defined_alias(self):
parser = ErrorRaisingArgumentParser()
subparsers = parser.add_subparsers()
subparsers.add_parser('foo')
self.assertWarns(DeprecationWarning, subparsers.add_parser, 'bar', aliases=['foo'])

# ============
# Groups tests
# ============
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2018-10-27-17-13-25.bpo-14856.F4DJr3.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Deprecate using add_parser() to overwrite an existing subparser.
Patch by Braden Groom