/brz/remove-bazaar

# Copyright (C) 2006-2010 Canonical Ltd

#

# 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Symbol versioning

The methods here allow for api symbol versioning.

"""

from __future__ import absolute_import

__all__ = ['deprecated_function',

           'deprecated_in',

           'deprecated_list',

           'deprecated_method',

           'DEPRECATED_PARAMETER',

           'deprecated_passed',

           'set_warning_method',

           'warn',

           ]

import warnings

# Import the 'warn' symbol so breezy can call it even if we redefine it

from warnings import warn

import breezy

DEPRECATED_PARAMETER = "A deprecated parameter marker."

def deprecated_in(version_tuple):

    """Generate a message that something was deprecated in a release.

    >>> deprecated_in((1, 4, 0))

    '%s was deprecated in version 1.4.0.'

    """

    return ("%%s was deprecated in version %s."

            % breezy._format_version_tuple(version_tuple))

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 deprecation_string(a_callable, deprecation_version):

    """Generate an automatic deprecation string for a_callable.

    :param a_callable: The callable to substitute into deprecation_version.

    :param deprecation_version: A deprecation format warning string. This

        should have a single %s operator in it. a_callable will be turned into

        a nice python symbol and then substituted into deprecation_version.

    """

    if getattr(a_callable, '__self__', None) is not None:

        symbol = "%s.%s.%s" % (a_callable.__self__.__class__.__module__,

                               a_callable.__self__.__class__.__name__,

                               a_callable.__name__)

    elif getattr(a_callable, '__qualname__', None) is not None and '<' not in a_callable.__qualname__:

        symbol = "%s.%s" % (a_callable.__module__,

                            a_callable.__qualname__)

    else:

        symbol = "%s.%s" % (a_callable.__module__,

                            a_callable.__name__)

    return deprecation_version % symbol

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."""

            from . import trace

            trace.mutter_callsite(4, "Deprecated function called")

            warn(deprecation_string(callable, deprecation_version),

                 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 a static or class method, use

        @staticmethod

        @deprecated_function

        def ...

    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."""

            from . import trace

            if callable.__name__ == '__init__':

                symbol = "%s.%s" % (self.__class__.__module__,

                                    self.__class__.__name__,

                                    )

            else:

                symbol = "%s.%s.%s" % (self.__class__.__module__,

                                       self.__class__.__name__,

                                       callable.__name__

                                       )

            trace.mutter_callsite(4, "Deprecated method called")

            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', deprecated_in((1, 5, 0))

    #

    # def __init__(self, bad=None)

    # def __init__(self, bad, other)

    # def __init__(self, **kwargs)

    # RBC 20060116

    return parameter_value is not 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

def _dict_deprecation_wrapper(wrapped_method):

    """Returns a closure that emits a warning and calls the superclass"""

    def cb(dep_dict, *args, **kwargs):

        msg = 'access to %s' % (dep_dict._variable_name, )

        msg = dep_dict._deprecation_version % (msg,)

        if dep_dict._advice:

            msg += ' ' + dep_dict._advice

        warn(msg, DeprecationWarning, stacklevel=2)

        return wrapped_method(dep_dict, *args, **kwargs)

    return cb

class DeprecatedDict(dict):

    """A dictionary that complains when read or written."""

    is_deprecated = True

    def __init__(self,

                 deprecation_version,

                 variable_name,

                 initial_value,

                 advice,

                 ):

        """Create a dict that warns when read or modified.

        :param deprecation_version: string for the warning format to raise,

            typically from deprecated_in()

        :param initial_value: The contents of the dict

        :param variable_name: This allows better warnings to be printed

        :param advice: String of advice on what callers should do instead

            of using this variable.

        """

        self._deprecation_version = deprecation_version

        self._variable_name = variable_name

        self._advice = advice

        dict.__init__(self, initial_value)

    # This isn't every possible method but it should trap anyone using the

    # dict -- add more if desired

    __len__ = _dict_deprecation_wrapper(dict.__len__)

    __getitem__ = _dict_deprecation_wrapper(dict.__getitem__)

    __setitem__ = _dict_deprecation_wrapper(dict.__setitem__)

    __delitem__ = _dict_deprecation_wrapper(dict.__delitem__)

    keys = _dict_deprecation_wrapper(dict.keys)

    __contains__ = _dict_deprecation_wrapper(dict.__contains__)

def deprecated_list(deprecation_version, variable_name,

                    initial_value, extra=None):

    """Create a list that warns when modified

    :param deprecation_version: string for the warning format to raise,

        typically from deprecated_in()

    :param initial_value: The contents of the list

    :param variable_name: This allows better warnings to be printed

    :param extra: Extra info to print when printing a warning

    """

    subst_text = 'Modifying %s' % (variable_name,)

    msg = deprecation_version % (subst_text,)

    if extra:

        msg += ' ' + extra

    class _DeprecatedList(list):

        __doc__ = list.__doc__ + msg

        is_deprecated = True

        def _warn_deprecated(self, func, *args, **kwargs):

            warn(msg, DeprecationWarning, stacklevel=3)

            return func(self, *args, **kwargs)

        def append(self, obj):

            """appending to %s is deprecated""" % (variable_name,)

            return self._warn_deprecated(list.append, obj)

        def insert(self, index, obj):

            """inserting to %s is deprecated""" % (variable_name,)

            return self._warn_deprecated(list.insert, index, obj)

        def extend(self, iterable):

            """extending %s is deprecated""" % (variable_name,)

            return self._warn_deprecated(list.extend, iterable)

        def remove(self, value):

            """removing from %s is deprecated""" % (variable_name,)

            return self._warn_deprecated(list.remove, value)

        def pop(self, index=None):

            """pop'ing from %s is deprecated""" % (variable_name,)

            if index:

                return self._warn_deprecated(list.pop, index)

            else:

                # Can't pass None

                return self._warn_deprecated(list.pop)

    return _DeprecatedList(initial_value)

def _check_for_filter(error_only):

    """Check if there is already a filter for deprecation warnings.

    :param error_only: Only match an 'error' filter

    :return: True if a filter is found, False otherwise

    """

    for filter in warnings.filters:

        if issubclass(DeprecationWarning, filter[2]):

            # This filter will effect DeprecationWarning

            if not error_only or filter[0] == 'error':

                return True

    return False

def _remove_filter_callable(filter):

    """Build and returns a callable removing filter from the warnings.

    :param filter: The filter to remove (can be None).

    :return: A callable that will remove filter from warnings.filters.

    """

    def cleanup():

        if filter:

            warnings.filters.remove(filter)

    return cleanup

def suppress_deprecation_warnings(override=True):

    """Call this function to suppress all deprecation warnings.

    When this is a final release version, we don't want to annoy users with

    lots of deprecation warnings. We only want the deprecation warnings when

    running a dev or release candidate.

    :param override: If True, always set the ignore, if False, only set the

        ignore if there isn't already a filter.

    :return: A callable to remove the new warnings this added.

    """

    if not override and _check_for_filter(error_only=False):

        # If there is already a filter effecting suppress_deprecation_warnings,

        # then skip it.

        filter = None

    else:

        warnings.filterwarnings('ignore', category=DeprecationWarning)

        filter = warnings.filters[0]

    return _remove_filter_callable(filter)

def activate_deprecation_warnings(override=True):

    """Call this function to activate deprecation warnings.

    When running in a 'final' release we suppress deprecation warnings.

    However, the test suite wants to see them. So when running selftest, we

    re-enable the deprecation warnings.

    Note: warnings that have already been issued under 'ignore' will not be

    reported after this point. The 'warnings' module has already marked them as

    handled, so they don't get issued again.

    :param override: If False, only add a filter if there isn't an error filter

        already. (This slightly differs from suppress_deprecation_warnings, in

        because it always overrides everything but -Werror).

    :return: A callable to remove the new warnings this added.

    """

    if not override and _check_for_filter(error_only=True):

        # DeprecationWarnings are already turned into errors, don't downgrade

        # them to 'default'.

        filter = None

    else:

        warnings.filterwarnings('default', category=DeprecationWarning)

        filter = warnings.filters[0]

    return _remove_filter_callable(filter)