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# Copyright (C) 2006 Canonical Ltd
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# Authors: Robert Collins <robert.collins@canonical.com>
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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The methods here allow for api symbol versioning.
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__all__ = ['deprecated_function',
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'DEPRECATED_PARAMETER',
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'warn', 'set_warning_method', 'zero_seven',
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from warnings import warn
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DEPRECATED_PARAMETER = "A deprecated parameter marker."
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zero_seven = "%s was deprecated in version 0.7."
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zero_eight = "%s was deprecated in version 0.8."
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zero_nine = "%s was deprecated in version 0.9."
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zero_ten = "%s was deprecated in version 0.10."
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zero_eleven = "%s was deprecated in version 0.11."
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zero_twelve = "%s was deprecated in version 0.12."
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zero_thirteen = "%s was deprecated in version 0.13."
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def set_warning_method(method):
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"""Set the warning method to be used by this module.
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It should take a message and a warning category as warnings.warn does.
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# TODO - maybe this would be easier to use as one 'smart' method that
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# guess if it is a method or a class or an attribute ? If so, we can
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# add that on top of the primitives, once we have all three written
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def deprecation_string(a_callable, deprecation_version):
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"""Generate an automatic deprecation string for a_callable.
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:param a_callable: The callable to substitute into deprecation_version.
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:param deprecation_version: A deprecation format warning string. This should
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have a single %s operator in it. a_callable will be turned into a nice
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python symbol and then substituted into deprecation_version.
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if getattr(a_callable, 'im_class', None) is None:
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symbol = "%s.%s" % (a_callable.__module__,
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symbol = "%s.%s.%s" % (a_callable.im_class.__module__,
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a_callable.im_class.__name__,
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return deprecation_version % symbol
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def deprecated_function(deprecation_version):
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"""Decorate a function so that use of it will trigger a warning."""
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def function_decorator(callable):
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"""This is the function python calls to perform the decoration."""
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def decorated_function(*args, **kwargs):
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"""This is the decorated function."""
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warn(deprecation_string(callable, deprecation_version),
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DeprecationWarning, stacklevel=2)
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return callable(*args, **kwargs)
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_populate_decorated(callable, deprecation_version, "function",
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return decorated_function
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return function_decorator
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def deprecated_method(deprecation_version):
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"""Decorate a method so that use of it will trigger a warning.
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To deprecate an entire class, decorate __init__.
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def method_decorator(callable):
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"""This is the function python calls to perform the decoration."""
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def decorated_method(self, *args, **kwargs):
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"""This is the decorated method."""
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symbol = "%s.%s.%s" % (self.__class__.__module__,
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self.__class__.__name__,
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warn(deprecation_version % symbol, DeprecationWarning, stacklevel=2)
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return callable(self, *args, **kwargs)
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_populate_decorated(callable, deprecation_version, "method",
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return decorated_method
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return method_decorator
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def deprecated_passed(parameter_value):
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"""Return True if parameter_value was used."""
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# FIXME: it might be nice to have a parameter deprecation decorator.
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# it would need to handle positional and *args and **kwargs parameters,
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# which means some mechanism to describe how the parameter was being
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# passed before deprecation, and some way to deprecate parameters that
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# were not at the end of the arg list. Thats needed for __init__ where
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# we cannot just forward to a new method name.I.e. in the following
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# examples we would want to have callers that pass any value to 'bad' be
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# given a warning - because we have applied:
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# @deprecated_parameter('bad', zero_seven)
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# def __init__(self, bad=None)
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# def __init__(self, bad, other)
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# def __init__(self, **kwargs)
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return not parameter_value is DEPRECATED_PARAMETER
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def _decorate_docstring(callable, deprecation_version, label,
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docstring_lines = callable.__doc__.split('\n')
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if len(docstring_lines) == 0:
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decorated_callable.__doc__ = deprecation_version % ("This " + label)
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elif len(docstring_lines) == 1:
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decorated_callable.__doc__ = (callable.__doc__
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+ deprecation_version % ("This " + label)
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spaces = len(docstring_lines[-1])
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new_doc = callable.__doc__
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new_doc += "\n" + " " * spaces
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new_doc += deprecation_version % ("This " + label)
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new_doc += "\n" + " " * spaces
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decorated_callable.__doc__ = new_doc
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def _populate_decorated(callable, deprecation_version, label,
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"""Populate attributes like __name__ and __doc__ on the decorated callable.
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_decorate_docstring(callable, deprecation_version, label,
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decorated_callable.__module__ = callable.__module__
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decorated_callable.__name__ = callable.__name__
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decorated_callable.is_deprecated = True
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def deprecated_list(deprecation_version, variable_name,
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initial_value, extra=None):
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"""Create a list that warns when modified
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:param deprecation_version: something like zero_nine
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:param initial_value: The contents of the list
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:param variable_name: This allows better warnings to be printed
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:param extra: Extra info to print when printing a warning
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subst_text = 'Modifying %s' % (variable_name,)
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msg = deprecation_version % (subst_text,)
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class _DeprecatedList(list):
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__doc__ = list.__doc__ + msg
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def _warn_deprecated(self, func, *args, **kwargs):
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warn(msg, DeprecationWarning, stacklevel=3)
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return func(self, *args, **kwargs)
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def append(self, obj):
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"""appending to %s is deprecated""" % (variable_name,)
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return self._warn_deprecated(list.append, obj)
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def insert(self, index, obj):
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"""inserting to %s is deprecated""" % (variable_name,)
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return self._warn_deprecated(list.insert, index, obj)
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def extend(self, iterable):
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"""extending %s is deprecated""" % (variable_name,)
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return self._warn_deprecated(list.extend, iterable)
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def remove(self, value):
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"""removing from %s is deprecated""" % (variable_name,)
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return self._warn_deprecated(list.remove, value)
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def pop(self, index=None):
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"""pop'ing from from %s is deprecated""" % (variable_name,)
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return self._warn_deprecated(list.pop, index)
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return self._warn_deprecated(list.pop)
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return _DeprecatedList(initial_value)