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Remove colorless theme monkeypatchfor argparse bug in 3.15.0b1 #1674

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Merged
tleonhardt merged 1 commit into from
Jun 3, 2026
Merged

Remove colorless theme monkeypatchfor argparse bug in 3.15.0b1 #1674

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24 changes: 0 additions & 24 deletions cmd2/argparse_utils.py
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Original file line number Diff line number Diff line change
Expand Up @@ -423,30 +423,6 @@ def _validate_completion_callable(self: argparse.Action, value: Any) -> Any:
register_argparse_argument_parameter("nargs_range")
register_argparse_argument_parameter("suppress_tab_hint")

############################################################################################################
# Workaround for Python 3.15.0b1 argparse bug
# _ColorlessTheme.__getattr__ incorrectly returns "" for non-public attributes, which breaks
# protocols like copy.deepcopy().
############################################################################################################

if sys.version_info >= (3, 15):

def _ColorlessTheme_getattr( # noqa: N802
_self: argparse._ColorlessTheme, # type: ignore[name-defined]
name: str,
) -> Any:
"""Patched __getattr__ that allows non-public lookups to fail correctly.

This matches the implementation in CPython for their next release.
"""
if name.startswith("_"):
raise AttributeError(name)
return ""

# If the bug still exists, then install the patch.
if getattr(argparse._ColorlessTheme(), "__deepcopy__", None) == "": # type: ignore[attr-defined]
argparse._ColorlessTheme.__getattr__ = _ColorlessTheme_getattr # type: ignore[attr-defined]


############################################################################################################
# Patch _ActionsContainer.add_argument to support more arguments
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19 changes: 0 additions & 19 deletions tests/test_argparse_utils.py
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Expand Up @@ -863,22 +863,3 @@ def test_deprecated_subcommand() -> None:
# Verify it was removed from _deprecated set
assert "old" not in subparsers_action._deprecated # type: ignore[attr-defined]
assert "old_alias" not in subparsers_action._deprecated # type: ignore[attr-defined]


@pytest.mark.skipif(
sys.version_info < (3, 15),
reason="_ColorlessTheme only exists in 3.15+",
)
def test_colorless_theme_monkeypatch() -> None:
"""Test the _ColorlessTheme.__getattr__ monkey patch."""

# If this assertion fails, then the bug no longer exists and our patch wasn't installed.
# We can remove the patch function and this test.
assert argparse._ColorlessTheme.__getattr__ == argparse_utils._ColorlessTheme_getattr

# Our patch raises an Attribute error for non-public.
with pytest.raises(AttributeError):
getattr(argparse._ColorlessTheme(), "_fake") # noqa: B009

with pytest.raises(AttributeError):
getattr(argparse._ColorlessTheme(), "__deepcopy__") # noqa: B009
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