"""
Utilities for helping robustly deprecate features.
"""
from __future__ import annotations
[docs]
def schedule_deprecation(
modname: str,
name: str = '?',
type: str = '?',
migration: str = '',
deprecate: str | None = None,
error: str | None = None,
remove: str | None = None,
) -> None:
"""
Deprecation machinery to help provide users with a smoother transition.
This function provides a concise way to mark a feature as deprecated by
providing a description of the deprecated feature, documentation on how to
migrate away from the deprecated feature, and the versions that the feature
is scheduled for deprecation and eventual removal. Based on the version of
the library and the specified schedule this function will either do
nothing, emit a warning, or raise an error with helpful messages for both
users and developers.
Args:
modname (str):
The name of the underlying module associated with the feature to be
deprecated. The module must already be imported and have a passable
``__version__`` attribute.
name (str):
The name of the feature to deprecate. This is usually a function or
argument name.
type (str):
A description of what the feature is. This is not a formal type,
but rather a prose description: e.g. "argument to my_func".
migration (str):
A description that lets users know what they should do instead of
using the deprecated feature.
deprecate (str | None):
The version when the feature is officially deprecated and this
function should start to emit a deprecation warning.
error (str | None):
The version when the feature is officially no longer supported, and
will start to raise a RuntimeError.
remove (str | None):
The version when the feature is completely removed. An
AssertionError will be raised if this function is still present
reminding the developer to remove the feature (or extend the remove
version).
Note:
The :class:`DeprecationWarning` is not visible by default.
https://docs.python.org/3/library/warnings.html
Example:
>>> import sys
>>> import types
>>> import pytest
>>> dummy_module = sys.modules['dummy_module'] = types.ModuleType('dummy_module')
>>> # When less than the deprecated version this does nothing
>>> dummy_module.__version__ = '1.0.0'
>>> schedule_deprecation(
... 'dummy_module', 'myfunc', 'function', 'do something else',
... deprecate='1.1.0', error='1.2.0', remove='1.3.0')
>>> # Now this raises warning
>>> with pytest.warns(DeprecationWarning):
... dummy_module.__version__ = '1.1.0'
... schedule_deprecation(
... 'dummy_module', 'myfunc', 'function', 'do something else',
... deprecate='1.1.0', error='1.2.0', remove='1.3.0')
>>> # Now this raises an error for the user
>>> with pytest.raises(RuntimeError):
... dummy_module.__version__ = '1.2.0'
... schedule_deprecation(
... 'dummy_module', 'myfunc', 'function', 'do something else',
... deprecate='1.1.0', error='1.2.0', remove='1.3.0')
>>> # Now this raises an error for the developer
>>> with pytest.raises(AssertionError):
... dummy_module.__version__ = '1.3.0'
... schedule_deprecation(
... 'dummy_module', 'myfunc', 'function', 'do something else',
... deprecate='1.1.0', error='1.2.0', remove='1.3.0')
>>> # When no versions are specified, it simply emits the warning
>>> with pytest.warns(DeprecationWarning):
... dummy_module.__version__ = '1.1.0'
... schedule_deprecation(
... 'dummy_module', 'myfunc', 'function', 'do something else')
"""
import sys
import warnings
try:
import packaging.version as _pkg_version
_parse_version = _pkg_version.parse
except ImportError:
import distutils.version as _dist_version # type: ignore[unresolved-import]
_parse_version = _dist_version.LooseVersion
module = sys.modules[modname]
current = _parse_version(module.__version__)
deprecate_v = _parse_version(deprecate) if deprecate is not None else None
remove_v = _parse_version(remove) if remove is not None else None
error_v = _parse_version(error) if error is not None else None
deprecate_str = '' if deprecate_v is None else f' in {deprecate_v}'
remove_str = '' if remove_v is None else f' in {remove_v}'
error_str = '' if error_v is None else f' in {error_v}'
if deprecate_v is None or current >= deprecate_v:
msg = (
(
'The "{name}" {type} was deprecated{deprecate_str}, will cause '
'an error{error_str} and will be removed{remove_str}. The current '
'version is {current}. {migration}'
)
.format(**locals())
.strip()
)
if remove_v is not None and current >= remove_v:
raise AssertionError(
'Forgot to remove deprecated: '
+ msg
+ ' '
+ 'Remove the function, or extend the scheduled remove version.'
)
if error_v is not None and current >= error_v:
raise RuntimeError(msg)
else:
warnings.warn(msg, DeprecationWarning)