Fixed #36321 -- Added argparse suggest_on_error support for Python 3.14+ #20021

kihuni · 2025-10-30T06:40:08Z

Trac ticket number

Branch description

This PR enables argparse's suggest_on_error feature for Django management commands when running on Python 3.14 or higher. This provides helpful suggestions when users mistype command arguments.

Checklist

This PR targets the main branch.
The commit message is written in past tense, mentions the ticket number, and ends with a period.
I have checked the "Has patch" ticket flag in the Trac system.
I have added or updated relevant tests.
I have added or updated relevant docs, including release notes if applicable.
I have attached screenshots in both light and dark modes for any UI changes.

felixxm · 2025-10-30T08:40:07Z

django/core/management/base.py

+
+        # Enable suggest_on_error for Python 3.14+
+        if sys.version_info >= (3, 14):
+            kwargs.setdefault("suggest_on_error", True)


Use PY314 from django.utils.version

Suggested change

# Enable suggest_on_error for Python 3.14+

if sys.version_info >= (3, 14):

kwargs.setdefault("suggest_on_error", True)

if PY314:

kwargs.setdefault("suggest_on_error", True)

felixxm · 2025-10-30T08:42:03Z

django/core/management/commands/makemessages.py

-                self.locale_paths.append(os.path.abspath("locale"))
+                locale_path = os.path.abspath("locale")
+                if locale_path not in self.locale_paths:
+                    self.locale_paths.append(locale_path)


I think you mixed this patch with some unrelated changes in makemessages, please remove them.

felixxm · 2025-10-30T08:42:26Z

docs/releases/5.2.txt


 * The ``all`` argument for the ``django.contrib.staticfiles.finders.find()``
  function is deprecated in favor of the ``find_all`` argument.
+


Revert unnecessary blank line.

felixxm · 2025-10-30T08:43:05Z

docs/releases/5.2.txt

+  running on Python 3.14+. This provides helpful suggestions when command-line
+  arguments are misspelled. For example, ``--verbositty`` will suggest
+  ``--verbosity``.
+


This should be moved to release notes for Django 6.1 (6.1.txt).

felixxm · 2025-10-30T08:43:56Z

tests/user_commands/tests.py

+        """
+        Explicitly passed suggest_on_error kwarg should not be overridden.
+        """
+        if sys.version_info >= (3, 14):


Use skipUnless decorator instead.

adamchainz

Thank you for working on this! Go go Djangonauts!

We'd also like to affect the parser created in django/core/management/__init__.py:ManagementUtility.execute, for manage.py usage.

Also, we need to ensure subparsers are affected, as created in CommandParser.add_subparsers().

I think it might be better to hoist defaulting the argument on in CommandParser.__init__(), so all call sites are affected.

…14+.

kihuni · 2025-11-02T06:18:43Z

Thank you for the reviews! @felixxm and @adamchainz, I've addressed all the feedback:

Changes made:

Moved the implementation from BaseCommand.create_parser() to CommandParser.__init__() as suggested. This ensures all parsers (including subparsers and the one in ManagementUtility.execute()) are affected.
Changed from sys.version_info >= (3, 14) to using the PY314 constant from django.utils.version as suggested.
Updated tests to use @skipUnless(PY314, ...) decorator instead of if statements.
Moved release notes from docs/releases/5.2.txt to docs/releases/6.1.txt.
Removed unrelated makemessages changes.
Fixed formatting issues (whitespace, line length).

…14+. When running Django management commands on Python 3.14 or higher, argparse's suggest_on_error feature is now enabled. This provides helpful suggestions when users mistype command-line arguments. For example, '--verbositty' will now suggest '--verbosity'.

adamchainz

Thanks for iterating. Here is another round of review!

I think I misunderstood the feature when writing up the ticket, and that's carried on in your implementation. Take a look at my comment in the test file. It would be good if you could also run a management command locally on Python 3.14+ with this branch, to see the suggestions working.

adamchainz · 2025-11-03T10:15:06Z

django/core/management/base.py

    ):
        self.missing_args_message = missing_args_message
        self.called_from_command_line = called_from_command_line
+        # Enable suggest_on_error for Python 3.14+


Vacuous comment, remove

Suggested change

# Enable suggest_on_error for Python 3.14+

adamchainz · 2025-11-03T10:20:09Z

docs/releases/6.1.txt

+* Management commands now use argparse's ``suggest_on_error`` feature when
+  running on Python 3.14+. This provides helpful suggestions when command-line
+  arguments are misspelled. For example, ``--verbositty`` will suggest
+  ``--verbosity``.


Let's link to the argparse documentation, where the feature is described with an example. Also, your example was incorrect, as noted below in the tests—this feature only offers suggestions for mistyped subparser names and argument choices.

Suggested change

* Management commands now use argparse's ``suggest_on_error`` feature when

running on Python 3.14+. This provides helpful suggestions when command-line

arguments are misspelled. For example, ``--verbositty`` will suggest

``--verbosity``.

* Management commands now set :class:`~argparse.ArgumentParser`\'s

``suggest_on_error`` argument to ``True`` by default on Python 3.14+, enabling

suggestions for mistyped subparser names and argument choices.

adamchainz · 2025-11-03T10:21:17Z

django/core/management/base.py

        self.missing_args_message = missing_args_message
        self.called_from_command_line = called_from_command_line
+        # Enable suggest_on_error for Python 3.14+
+        if PY314 and called_from_command_line:


I just spotted that the default has flipped to True on Python 3.15: python/cpython@d2f3cfd

Therefore, let's change the check to:

Suggested change

if PY314 and called_from_command_line:

if PY314 and not PY315 and called_from_command_line:

# Adopt Python 3.15 default early.

This way, when we drop Python 3.14 support, it should be clear that we can remove this block.

adamchainz · 2025-11-03T10:23:18Z

tests/user_commands/tests.py

+class SuggestOnErrorTests(SimpleTestCase):
+    """
+    Tests for argparse suggest_on_error feature on Python 3.14+.
+    """


These tests do not need a dedicated test case and can be placed at the end of CommandTests

adamchainz · 2025-11-03T10:27:03Z

tests/user_commands/tests.py

+    def test_parser_kwargs_suggest_on_error_on_python_314_plus(self):
+        """
+        CommandParser sets suggest_on_error=True on Python 3.14+.
+        """
+        command = BaseCommand()
+        command._called_from_command_line = True  # ADD THIS LINE
+        parser = command.create_parser("prog_name", "subcommand")
+
+        if PY314:
+            self.assertTrue(
+                getattr(parser, "suggest_on_error", False),
+                "Parser should have suggest_on_error=True on Python 3.14+",
+            )
+
+    @unittest.skipUnless(PY314, "Requires Python 3.14+")
+    def test_custom_suggest_on_error_respected(self):
+        """
+        Explicit suggest_on_error=False is respected.
+        """
+        command = BaseCommand()
+        command._called_from_command_line = True  # ADD THIS LINE
+        parser = command.create_parser(
+            "prog_name", "subcommand", suggest_on_error=False
+        )
+        self.assertFalse(
+            parser.suggest_on_error,
+            "Explicit suggest_on_error=False is respected",
+        )
+
+    @unittest.skipUnless(PY314, "Requires Python 3.14+")
+    def test_misspelled_option_suggests_correct_option(self):
+        """
+        On Python 3.14+, misspelled options trigger suggestions when available.
+        """
+        command = BaseCommand()
+        command._called_from_command_line = True
+        parser = command.create_parser("django-admin", "test")
+
+        err = StringIO()
+        with mock.patch("sys.stderr", err):
+            with self.assertRaises(SystemExit) as cm:
+                parser.parse_args(["--verbositty", "2"])
+        self.assertEqual(cm.exception.code, 2)
+
+        error_output = err.getvalue().lower()
+        # Ensure it failed for the right reason
+        self.assertIn("unrecognized arguments", error_output)
+
+        # On Python 3.14+, suggestions *may* appear depending on environment
+        if "did you mean" in error_output:
+            self.assertIn("--verbosity", error_output)
+
+    def test_suggest_on_error_works_with_management_commands(self):
+        """
+        Management commands have suggest_on_error on Python 3.14+.
+        """
+        from .management.commands.dance import Command as DanceCommand
+
+        dance_cmd = DanceCommand()
+        dance_cmd._called_from_command_line = True  # ADD THIS LINE
+        parser = dance_cmd.create_parser("django-admin", "dance")
+
+        if PY314:
+            self.assertTrue(
+                getattr(parser, "suggest_on_error", False),
+                "Management command parsers should have suggest_on_error=True",
+            )


Some fixes for your tests:

Use unittest.skipUnless on all tests.

Use not PY315 per the above comments about the default chanigng on Python 3.15.

Drop the # ADD THIS LINE comments, which look like they came from someone's review?

Drop the behaviour tests - they are not valuable, as they only test argparse's behaviour, which we can depend on.

Suggested change

def test_parser_kwargs_suggest_on_error_on_python_314_plus(self):

"""

CommandParser sets suggest_on_error=True on Python 3.14+.

"""

command = BaseCommand()

command._called_from_command_line = True # ADD THIS LINE

parser = command.create_parser("prog_name", "subcommand")

if PY314:

self.assertTrue(

getattr(parser, "suggest_on_error", False),

"Parser should have suggest_on_error=True on Python 3.14+",

)

@unittest.skipUnless(PY314, "Requires Python 3.14+")

def test_custom_suggest_on_error_respected(self):

"""

Explicit suggest_on_error=False is respected.

"""

command = BaseCommand()

command._called_from_command_line = True # ADD THIS LINE

parser = command.create_parser(

"prog_name", "subcommand", suggest_on_error=False

)

self.assertFalse(

parser.suggest_on_error,

"Explicit suggest_on_error=False is respected",

)

@unittest.skipUnless(PY314, "Requires Python 3.14+")

def test_misspelled_option_suggests_correct_option(self):

"""

On Python 3.14+, misspelled options trigger suggestions when available.

"""

command = BaseCommand()

command._called_from_command_line = True

parser = command.create_parser("django-admin", "test")

err = StringIO()

with mock.patch("sys.stderr", err):

with self.assertRaises(SystemExit) as cm:

parser.parse_args(["--verbositty", "2"])

self.assertEqual(cm.exception.code, 2)

error_output = err.getvalue().lower()

# Ensure it failed for the right reason

self.assertIn("unrecognized arguments", error_output)

# On Python 3.14+, suggestions *may* appear depending on environment

if "did you mean" in error_output:

self.assertIn("--verbosity", error_output)

def test_suggest_on_error_works_with_management_commands(self):

"""

Management commands have suggest_on_error on Python 3.14+.

"""

from .management.commands.dance import Command as DanceCommand

dance_cmd = DanceCommand()

dance_cmd._called_from_command_line = True # ADD THIS LINE

parser = dance_cmd.create_parser("django-admin", "dance")

if PY314:

self.assertTrue(

getattr(parser, "suggest_on_error", False),

"Management command parsers should have suggest_on_error=True",

)

@unittest.skipUnless(PY314 and not PY315, "Requires Python 3.14")

def test_suggest_on_error_defaults_true(self):

"""

CommandParser sets suggest_on_error=True on Python 3.14+.

"""

command = BaseCommand()

command._called_from_command_line = True

parser = command.create_parser("prog_name", "subcommand")

self.assertTrue(parser.suggest_on_error)

@unittest.skipUnless(PY314 and not PY315, "Requires Python 3.14+")

def test_suggest_on_error_custom(self):

"""

Explicit suggest_on_error=False is respected.

"""

command = BaseCommand()

command._called_from_command_line = True

parser = command.create_parser(

"prog_name", "subcommand", suggest_on_error=False

)

self.assertFalse(parser.suggest_on_error)

adamchainz · 2025-11-03T10:46:47Z

tests/user_commands/tests.py

+        # On Python 3.14+, suggestions *may* appear depending on environment
+        if "did you mean" in error_output:
+            self.assertIn("--verbosity", error_output)


This test was not testing the correct output, or expecting the right correction. suggest_on_error does not affect mistyped options. It affects mistyped option choices and subparser names.

The way I'm testing it manually is:

$ python -m django check --fail-level EROR ... __main__.py check: error: argument --fail-level: invalid choice: 'EROR', maybe you meant 'ERROR'? (choose from CRITICAL, ERROR, WARNING, INFO, DEBUG)

Note the "maybe you meant 'ERROR'?"

I don't think argparse has any feature to suggest for mistyped options at current. Did you see this assertion pass on any environment?

You're right @adamchainz, I apologize for the confusion. I did not actually test this on Python 3.14+. I was working on Python 3.12 and wrote tests based on the ticket description, which turned out to be incorrect about what suggest_on_error does.

Thank you for the clarification that it only affects:

Mistyped argument choices (like --fail-level EROR → ERROR)

Mistyped subparser names (like python manage.py chek → check)

And NOT mistyped option flags (like --verbositty).

I've removed the incorrect behavioral test. The remaining two tests just verify that the setting is applied correctly, which is appropriate since we're relying on argparse's implementation.

The ticket description should probably be updated to reflect the actual behavior of this feature.

When running Django management commands on Python 3.14, argparse's suggest_on_error feature is now enabled. This provides helpful suggestions for mistyped subparser names and argument choices.

github-actions bot added the no ticket Based on PR title, no linked Trac ticket label Oct 30, 2025

kihuni changed the title ~~Ticket 36321~~ Fixed #36321 -- Added argparse suggest_on_error support for Python 3.14+ Oct 30, 2025

github-actions bot removed the no ticket Based on PR title, no linked Trac ticket label Oct 30, 2025

felixxm reviewed Oct 30, 2025

View reviewed changes

jacobtylerwalls added the Djangonauts 🚀 label Oct 30, 2025

adamchainz suggested changes Oct 30, 2025

View reviewed changes

Fixed #36321 -- Added argparse suggest_on_error support for Python 3.…

0d857ea

…14+.

kihuni force-pushed the ticket_36321 branch from 2a6f2b5 to 0d857ea Compare November 2, 2025 05:51

kihuni force-pushed the ticket_36321 branch 2 times, most recently from 5915f40 to d9b67db Compare November 2, 2025 06:50

kihuni force-pushed the ticket_36321 branch 2 times, most recently from e66062f to e395caf Compare November 2, 2025 09:08

adamchainz suggested changes Nov 3, 2025

View reviewed changes

Fixed #36321 -- Added argparse suggest_on_error support for Python 3.14.

3af2f04

When running Django management commands on Python 3.14, argparse's suggest_on_error feature is now enabled. This provides helpful suggestions for mistyped subparser names and argument choices.

kihuni force-pushed the ticket_36321 branch from 475a089 to 3af2f04 Compare November 5, 2025 21:10


		* The ``all`` argument for the ``django.contrib.staticfiles.finders.find()``
		function is deprecated in favor of the ``find_all`` argument.

	if PY314 and called_from_command_line:
	if PY314 and not PY315 and called_from_command_line:
	# Adopt Python 3.15 default early.

Uh oh!

Fixed #36321 -- Added argparse suggest_on_error support for Python 3.14+ #20021

Are you sure you want to change the base?

Fixed #36321 -- Added argparse suggest_on_error support for Python 3.14+ #20021

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kihuni commented Oct 30, 2025 •

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