# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of logilab-common.
#
# logilab-common is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option) any
# later version.
#
# logilab-common 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-common. If not, see <http://www.gnu.org/licenses/>.
"""Deprecation utilities."""
__docformat__ = "restructuredtext en"
import sys
from warnings import warn
from logilab.common.changelog import Version
class DeprecationWrapper(object):
"""proxy to print a warning on access to any attribute of the wrapped object
"""
def __init__(self, proxied, msg=None):
self._proxied = proxied
self._msg = msg
def __getattr__(self, attr):
warn(self._msg, DeprecationWarning, stacklevel=2)
return getattr(self._proxied, attr)
def __setattr__(self, attr, value):
if attr in ('_proxied', '_msg'):
self.__dict__[attr] = value
else:
warn(self._msg, DeprecationWarning, stacklevel=2)
setattr(self._proxied, attr, value)
class DeprecationManager(object):
"""Manage the deprecation message handling. Messages are dropped for
versions more recent than the 'compatible' version. Example::
deprecator = deprecation.DeprecationManager("module_name")
deprecator.compatibility('1.3')
deprecator.warn('1.2', "message.")
@deprecator.deprecated('1.2', 'Message')
def any_func():
pass
class AnyClass(object):
__metaclass__ = deprecator.class_deprecated('1.2')
"""
def __init__(self, module_name=None):
"""
"""
self.module_name = module_name
self.compatible_version = None
def compatibility(self, compatible_version):
"""Set the compatible version.
"""
self.compatible_version = Version(compatible_version)
def deprecated(self, version=None, reason=None, stacklevel=2, name=None, doc=None):
"""Display a deprecation message only if the version is older than the
compatible version.
"""
def decorator(func):
message = reason or 'The function "%s" is deprecated'
if '%s' in message:
message %= func.__name__
def wrapped(*args, **kwargs):
self.warn(version, message, stacklevel+1)
return func(*args, **kwargs)
return wrapped
return decorator
def class_deprecated(self, version=None):
class metaclass(type):
"""metaclass to print a warning on instantiation of a deprecated class"""
def __call__(cls, *args, **kwargs):
msg = getattr(cls, "__deprecation_warning__",
"%(cls)s is deprecated") % {'cls': cls.__name__}
self.warn(version, msg, stacklevel=3)
return type.__call__(cls, *args, **kwargs)
return metaclass
def moved(self, version, modpath, objname):
"""use to tell that a callable has been moved to a new module.
It returns a callable wrapper, so that when its called a warning is printed
telling where the object can be found, import is done (and not before) and
the actual object is called.
NOTE: the usage is somewhat limited on classes since it will fail if the
wrapper is use in a class ancestors list, use the `class_moved` function
instead (which has no lazy import feature though).
"""
def callnew(*args, **kwargs):
from logilab.common.modutils import load_module_from_name
message = "object %s has been moved to module %s" % (objname, modpath)
self.warn(version, message)
m = load_module_from_name(modpath)
return getattr(m, objname)(*args, **kwargs)
return callnew
def class_renamed(self, version, old_name, new_class, message=None):
clsdict = {}
if message is None:
message = '%s is deprecated, use %s' % (old_name, new_class.__name__)
clsdict['__deprecation_warning__'] = message
try:
# new-style class
return self.class_deprecated(version)(old_name, (new_class,), clsdict)
except (NameError, TypeError):
# old-style class
warn = self.warn
class DeprecatedClass(new_class):
"""FIXME: There might be a better way to handle old/new-style class
"""
def __init__(self, *args, **kwargs):
warn(version, message, stacklevel=3)
new_class.__init__(self, *args, **kwargs)
return DeprecatedClass
def class_moved(self, version, new_class, old_name=None, message=None):
"""nice wrapper around class_renamed when a class has been moved into
another module
"""
if old_name is None:
old_name = new_class.__name__
if message is None:
message = 'class %s is now available as %s.%s' % (
old_name, new_class.__module__, new_class.__name__)
return self.class_renamed(version, old_name, new_class, message)
def warn(self, version=None, reason="", stacklevel=2):
"""Display a deprecation message only if the version is older than the
compatible version.
"""
if (self.compatible_version is None
or version is None
or Version(version) < self.compatible_version):
if self.module_name and version:
reason = '[%s %s] %s' % (self.module_name, version, reason)
elif self.module_name:
reason = '[%s] %s' % (self.module_name, reason)
elif version:
reason = '[%s] %s' % (version, reason)
warn(reason, DeprecationWarning, stacklevel=stacklevel)
_defaultdeprecator = DeprecationManager()
def deprecated(reason=None, stacklevel=2, name=None, doc=None):
return _defaultdeprecator.deprecated(None, reason, stacklevel, name, doc)
class_deprecated = _defaultdeprecator.class_deprecated()
def moved(modpath, objname):
return _defaultdeprecator.moved(None, modpath, objname)
moved.__doc__ = _defaultdeprecator.moved.__doc__
def class_renamed(old_name, new_class, message=None):
"""automatically creates a class which fires a DeprecationWarning
when instantiated.
>>> Set = class_renamed('Set', set, 'Set is now replaced by set')
>>> s = Set()
sample.py:57: DeprecationWarning: Set is now replaced by set
s = Set()
>>>
"""
return _defaultdeprecator.class_renamed(None, old_name, new_class, message)
def class_moved(new_class, old_name=None, message=None):
return _defaultdeprecator.class_moved(None, new_class, old_name, message)
class_moved.__doc__ = _defaultdeprecator.class_moved.__doc__
