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# Copyright (C) 2006 by Canonical Ltd
# Authors: Robert Collins <robert.collins@canonical.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""Symbol versioning
The methods here allow for api symbol versioning.
"""
__all__ = ['deprecated_function',
'deprecated_method',
'DEPRECATED_PARAMETER',
'deprecated_passed',
'warn', 'set_warning_method', 'zero_seven',
'zero_eight', 'zero_nine'
]
from warnings import warn
DEPRECATED_PARAMETER = "A deprecated parameter marker."
zero_seven = "%s was deprecated in version 0.7."
zero_eight = "%s was deprecated in version 0.8."
zero_nine = "%s was deprecated in version 0.9."
def set_warning_method(method):
"""Set the warning method to be used by this module.
It should take a message and a warning category as warnings.warn does.
"""
global warn
warn = method
# TODO - maybe this would be easier to use as one 'smart' method that
# guess if it is a method or a class or an attribute ? If so, we can
# add that on top of the primitives, once we have all three written
# - RBC 20050105
def deprecated_function(deprecation_version):
"""Decorate a function so that use of it will trigger a warning."""
def function_decorator(callable):
"""This is the function python calls to perform the decoration."""
def decorated_function(*args, **kwargs):
"""This is the decorated function."""
symbol = "%s.%s" % (callable.__module__,
callable.__name__
)
warn(deprecation_version % symbol, DeprecationWarning, stacklevel=2)
return callable(*args, **kwargs)
_populate_decorated(callable, deprecation_version, "function",
decorated_function)
return decorated_function
return function_decorator
def deprecated_method(deprecation_version):
"""Decorate a method so that use of it will trigger a warning.
To deprecate an entire class, decorate __init__.
"""
def method_decorator(callable):
"""This is the function python calls to perform the decoration."""
def decorated_method(self, *args, **kwargs):
"""This is the decorated method."""
symbol = "%s.%s.%s" % (self.__class__.__module__,
self.__class__.__name__,
callable.__name__
)
warn(deprecation_version % symbol, DeprecationWarning, stacklevel=2)
return callable(self, *args, **kwargs)
_populate_decorated(callable, deprecation_version, "method",
decorated_method)
return decorated_method
return method_decorator
def deprecated_passed(parameter_value):
"""Return True if parameter_value was used."""
# FIXME: it might be nice to have a parameter deprecation decorator.
# it would need to handle positional and *args and **kwargs parameters,
# which means some mechanism to describe how the parameter was being
# passed before deprecation, and some way to deprecate parameters that
# were not at the end of the arg list. Thats needed for __init__ where
# we cannot just forward to a new method name.I.e. in the following
# examples we would want to have callers that pass any value to 'bad' be
# given a warning - because we have applied:
# @deprecated_parameter('bad', zero_seven)
#
# def __init__(self, bad=None)
# def __init__(self, bad, other)
# def __init__(self, **kwargs)
# RBC 20060116
return not parameter_value is DEPRECATED_PARAMETER
def _decorate_docstring(callable, deprecation_version, label,
decorated_callable):
if callable.__doc__:
docstring_lines = callable.__doc__.split('\n')
else:
docstring_lines = []
if len(docstring_lines) == 0:
decorated_callable.__doc__ = deprecation_version % ("This " + label)
elif len(docstring_lines) == 1:
decorated_callable.__doc__ = (callable.__doc__
+ "\n"
+ "\n"
+ deprecation_version % ("This " + label)
+ "\n")
else:
spaces = len(docstring_lines[-1])
new_doc = callable.__doc__
new_doc += "\n" + " " * spaces
new_doc += deprecation_version % ("This " + label)
new_doc += "\n" + " " * spaces
decorated_callable.__doc__ = new_doc
def _populate_decorated(callable, deprecation_version, label,
decorated_callable):
"""Populate attributes like __name__ and __doc__ on the decorated callable.
"""
_decorate_docstring(callable, deprecation_version, label,
decorated_callable)
decorated_callable.__module__ = callable.__module__
decorated_callable.__name__ = callable.__name__
decorated_callable.is_deprecated = True
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