613 lines
20 KiB
Python
613 lines
20 KiB
Python
# -*- test-case-name: twisted.python.test.test_deprecate -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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Deprecation framework for Twisted.
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To mark a method or function as being deprecated do this::
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from twisted.python.versions import Version
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from twisted.python.deprecate import deprecated
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@deprecated(Version("Twisted", 8, 0, 0))
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def badAPI(self, first, second):
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'''
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Docstring for badAPI.
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'''
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...
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The newly-decorated badAPI will issue a warning when called. It will also have
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a deprecation notice appended to its docstring.
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To mark module-level attributes as being deprecated you can use::
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badAttribute = "someValue"
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...
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deprecatedModuleAttribute(
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Version("Twisted", 8, 0, 0),
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"Use goodAttribute instead.",
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"your.full.module.name",
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"badAttribute")
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The deprecated attributes will issue a warning whenever they are accessed. If
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the attributes being deprecated are in the same module as the
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L{deprecatedModuleAttribute} call is being made from, the C{__name__} global
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can be used as the C{moduleName} parameter.
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See also L{Version}.
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@type DEPRECATION_WARNING_FORMAT: C{str}
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@var DEPRECATION_WARNING_FORMAT: The default deprecation warning string format
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to use when one is not provided by the user.
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"""
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from __future__ import division, absolute_import
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__all__ = [
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'deprecated',
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'getDeprecationWarningString',
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'getWarningMethod',
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'setWarningMethod',
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'deprecatedModuleAttribute',
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]
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import sys, inspect
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from warnings import warn, warn_explicit
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from dis import findlinestarts
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from functools import wraps
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from twisted.python.versions import getVersionString
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DEPRECATION_WARNING_FORMAT = '%(fqpn)s was deprecated in %(version)s'
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# Notionally, part of twisted.python.reflect, but defining it there causes a
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# cyclic dependency between this module and that module. Define it here,
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# instead, and let reflect import it to re-expose to the public.
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def _fullyQualifiedName(obj):
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"""
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Return the fully qualified name of a module, class, method or function.
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Classes and functions need to be module level ones to be correctly
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qualified.
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@rtype: C{str}.
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"""
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try:
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name = obj.__qualname__
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except AttributeError:
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name = obj.__name__
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if inspect.isclass(obj) or inspect.isfunction(obj):
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moduleName = obj.__module__
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return "%s.%s" % (moduleName, name)
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elif inspect.ismethod(obj):
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try:
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cls = obj.im_class
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except AttributeError:
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# Python 3 eliminates im_class, substitutes __module__ and
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# __qualname__ to provide similar information.
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return "%s.%s" % (obj.__module__, obj.__qualname__)
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else:
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className = _fullyQualifiedName(cls)
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return "%s.%s" % (className, name)
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return name
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# Try to keep it looking like something in twisted.python.reflect.
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_fullyQualifiedName.__module__ = 'twisted.python.reflect'
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_fullyQualifiedName.__name__ = 'fullyQualifiedName'
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_fullyQualifiedName.__qualname__ = 'fullyQualifiedName'
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def _getReplacementString(replacement):
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"""
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Surround a replacement for a deprecated API with some polite text exhorting
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the user to consider it as an alternative.
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@type replacement: C{str} or callable
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@return: a string like "please use twisted.python.modules.getModule
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instead".
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"""
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if callable(replacement):
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replacement = _fullyQualifiedName(replacement)
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return "please use %s instead" % (replacement,)
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def _getDeprecationDocstring(version, replacement=None):
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"""
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Generate an addition to a deprecated object's docstring that explains its
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deprecation.
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@param version: the version it was deprecated.
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@type version: L{Version}
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@param replacement: The replacement, if specified.
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@type replacement: C{str} or callable
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@return: a string like "Deprecated in Twisted 27.2.0; please use
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twisted.timestream.tachyon.flux instead."
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"""
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doc = "Deprecated in %s" % (getVersionString(version),)
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if replacement:
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doc = "%s; %s" % (doc, _getReplacementString(replacement))
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return doc + "."
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def _getDeprecationWarningString(fqpn, version, format=None, replacement=None):
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"""
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Return a string indicating that the Python name was deprecated in the given
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version.
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@param fqpn: Fully qualified Python name of the thing being deprecated
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@type fqpn: C{str}
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@param version: Version that C{fqpn} was deprecated in.
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@type version: L{twisted.python.versions.Version}
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@param format: A user-provided format to interpolate warning values into, or
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L{DEPRECATION_WARNING_FORMAT
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<twisted.python.deprecate.DEPRECATION_WARNING_FORMAT>} if C{None} is
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given.
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@type format: C{str}
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@param replacement: what should be used in place of C{fqpn}. Either pass in
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a string, which will be inserted into the warning message, or a
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callable, which will be expanded to its full import path.
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@type replacement: C{str} or callable
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@return: A textual description of the deprecation
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@rtype: C{str}
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"""
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if format is None:
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format = DEPRECATION_WARNING_FORMAT
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warningString = format % {
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'fqpn': fqpn,
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'version': getVersionString(version)}
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if replacement:
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warningString = "%s; %s" % (
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warningString, _getReplacementString(replacement))
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return warningString
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def getDeprecationWarningString(callableThing, version, format=None,
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replacement=None):
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"""
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Return a string indicating that the callable was deprecated in the given
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version.
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@type callableThing: C{callable}
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@param callableThing: Callable object to be deprecated
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@type version: L{twisted.python.versions.Version}
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@param version: Version that C{callableThing} was deprecated in
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@type format: C{str}
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@param format: A user-provided format to interpolate warning values into,
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or L{DEPRECATION_WARNING_FORMAT
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<twisted.python.deprecate.DEPRECATION_WARNING_FORMAT>} if C{None} is
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given
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@param callableThing: A callable to be deprecated.
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@param version: The L{twisted.python.versions.Version} that the callable
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was deprecated in.
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@param replacement: what should be used in place of the callable. Either
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pass in a string, which will be inserted into the warning message,
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or a callable, which will be expanded to its full import path.
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@type replacement: C{str} or callable
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@return: A string describing the deprecation.
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@rtype: C{str}
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"""
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return _getDeprecationWarningString(
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_fullyQualifiedName(callableThing), version, format, replacement)
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def _appendToDocstring(thingWithDoc, textToAppend):
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"""
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Append the given text to the docstring of C{thingWithDoc}.
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If C{thingWithDoc} has no docstring, then the text just replaces the
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docstring. If it has a single-line docstring then it appends a blank line
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and the message text. If it has a multi-line docstring, then in appends a
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blank line a the message text, and also does the indentation correctly.
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"""
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if thingWithDoc.__doc__:
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docstringLines = thingWithDoc.__doc__.splitlines()
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else:
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docstringLines = []
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if len(docstringLines) == 0:
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docstringLines.append(textToAppend)
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elif len(docstringLines) == 1:
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docstringLines.extend(['', textToAppend, ''])
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else:
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spaces = docstringLines.pop()
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docstringLines.extend(['',
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spaces + textToAppend,
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spaces])
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thingWithDoc.__doc__ = '\n'.join(docstringLines)
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def deprecated(version, replacement=None):
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"""
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Return a decorator that marks callables as deprecated.
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@type version: L{twisted.python.versions.Version}
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@param version: The version in which the callable will be marked as
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having been deprecated. The decorated function will be annotated
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with this version, having it set as its C{deprecatedVersion}
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attribute.
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@param version: the version that the callable was deprecated in.
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@type version: L{twisted.python.versions.Version}
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@param replacement: what should be used in place of the callable. Either
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pass in a string, which will be inserted into the warning message,
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or a callable, which will be expanded to its full import path.
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@type replacement: C{str} or callable
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"""
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def deprecationDecorator(function):
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"""
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Decorator that marks C{function} as deprecated.
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"""
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warningString = getDeprecationWarningString(
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function, version, None, replacement)
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@wraps(function)
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def deprecatedFunction(*args, **kwargs):
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warn(
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warningString,
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DeprecationWarning,
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stacklevel=2)
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return function(*args, **kwargs)
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_appendToDocstring(deprecatedFunction,
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_getDeprecationDocstring(version, replacement))
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deprecatedFunction.deprecatedVersion = version
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return deprecatedFunction
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return deprecationDecorator
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def getWarningMethod():
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"""
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Return the warning method currently used to record deprecation warnings.
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"""
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return warn
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def setWarningMethod(newMethod):
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"""
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Set the warning method to use to record deprecation warnings.
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The callable should take message, category and stacklevel. The return
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value is ignored.
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"""
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global warn
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warn = newMethod
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class _InternalState(object):
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"""
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An L{_InternalState} is a helper object for a L{_ModuleProxy}, so that it
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can easily access its own attributes, bypassing its logic for delegating to
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another object that it's proxying for.
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@ivar proxy: a L{ModuleProxy}
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"""
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def __init__(self, proxy):
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object.__setattr__(self, 'proxy', proxy)
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def __getattribute__(self, name):
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return object.__getattribute__(object.__getattribute__(self, 'proxy'),
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name)
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def __setattr__(self, name, value):
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return object.__setattr__(object.__getattribute__(self, 'proxy'),
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name, value)
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class _ModuleProxy(object):
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"""
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Python module wrapper to hook module-level attribute access.
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Access to deprecated attributes first checks
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L{_ModuleProxy._deprecatedAttributes}, if the attribute does not appear
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there then access falls through to L{_ModuleProxy._module}, the wrapped
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module object.
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@ivar _module: Module on which to hook attribute access.
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@type _module: C{module}
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@ivar _deprecatedAttributes: Mapping of attribute names to objects that
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retrieve the module attribute's original value.
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@type _deprecatedAttributes: C{dict} mapping C{str} to
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L{_DeprecatedAttribute}
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@ivar _lastWasPath: Heuristic guess as to whether warnings about this
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package should be ignored for the next call. If the last attribute
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access of this module was a C{getattr} of C{__path__}, we will assume
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that it was the import system doing it and we won't emit a warning for
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the next access, even if it is to a deprecated attribute. The CPython
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import system always tries to access C{__path__}, then the attribute
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itself, then the attribute itself again, in both successful and failed
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cases.
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@type _lastWasPath: C{bool}
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"""
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def __init__(self, module):
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state = _InternalState(self)
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state._module = module
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state._deprecatedAttributes = {}
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state._lastWasPath = False
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def __repr__(self):
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"""
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Get a string containing the type of the module proxy and a
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representation of the wrapped module object.
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"""
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state = _InternalState(self)
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return '<%s module=%r>' % (type(self).__name__, state._module)
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def __setattr__(self, name, value):
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"""
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Set an attribute on the wrapped module object.
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"""
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state = _InternalState(self)
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state._lastWasPath = False
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setattr(state._module, name, value)
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def __getattribute__(self, name):
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"""
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Get an attribute from the module object, possibly emitting a warning.
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If the specified name has been deprecated, then a warning is issued.
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(Unless certain obscure conditions are met; see
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L{_ModuleProxy._lastWasPath} for more information about what might quash
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such a warning.)
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"""
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state = _InternalState(self)
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if state._lastWasPath:
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deprecatedAttribute = None
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else:
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deprecatedAttribute = state._deprecatedAttributes.get(name)
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if deprecatedAttribute is not None:
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# If we have a _DeprecatedAttribute object from the earlier lookup,
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# allow it to issue the warning.
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value = deprecatedAttribute.get()
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else:
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# Otherwise, just retrieve the underlying value directly; it's not
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# deprecated, there's no warning to issue.
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value = getattr(state._module, name)
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if name == '__path__':
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state._lastWasPath = True
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else:
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state._lastWasPath = False
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return value
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class _DeprecatedAttribute(object):
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"""
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Wrapper for deprecated attributes.
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This is intended to be used by L{_ModuleProxy}. Calling
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L{_DeprecatedAttribute.get} will issue a warning and retrieve the
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underlying attribute's value.
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@type module: C{module}
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@ivar module: The original module instance containing this attribute
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@type fqpn: C{str}
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@ivar fqpn: Fully qualified Python name for the deprecated attribute
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@type version: L{twisted.python.versions.Version}
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@ivar version: Version that the attribute was deprecated in
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@type message: C{str}
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@ivar message: Deprecation message
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"""
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def __init__(self, module, name, version, message):
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"""
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Initialise a deprecated name wrapper.
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"""
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self.module = module
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self.__name__ = name
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self.fqpn = module.__name__ + '.' + name
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self.version = version
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self.message = message
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def get(self):
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"""
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Get the underlying attribute value and issue a deprecation warning.
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"""
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# This might fail if the deprecated thing is a module inside a package.
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# In that case, don't emit the warning this time. The import system
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# will come back again when it's not an AttributeError and we can emit
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# the warning then.
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result = getattr(self.module, self.__name__)
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message = _getDeprecationWarningString(self.fqpn, self.version,
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DEPRECATION_WARNING_FORMAT + ': ' + self.message)
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warn(message, DeprecationWarning, stacklevel=3)
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return result
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def _deprecateAttribute(proxy, name, version, message):
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"""
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Mark a module-level attribute as being deprecated.
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@type proxy: L{_ModuleProxy}
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@param proxy: The module proxy instance proxying the deprecated attributes
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@type name: C{str}
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@param name: Attribute name
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@type version: L{twisted.python.versions.Version}
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@param version: Version that the attribute was deprecated in
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@type message: C{str}
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@param message: Deprecation message
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"""
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_module = object.__getattribute__(proxy, '_module')
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attr = _DeprecatedAttribute(_module, name, version, message)
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# Add a deprecated attribute marker for this module's attribute. When this
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# attribute is accessed via _ModuleProxy a warning is emitted.
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_deprecatedAttributes = object.__getattribute__(
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proxy, '_deprecatedAttributes')
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_deprecatedAttributes[name] = attr
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def deprecatedModuleAttribute(version, message, moduleName, name):
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"""
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Declare a module-level attribute as being deprecated.
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@type version: L{twisted.python.versions.Version}
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@param version: Version that the attribute was deprecated in
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@type message: C{str}
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@param message: Deprecation message
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@type moduleName: C{str}
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@param moduleName: Fully-qualified Python name of the module containing
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the deprecated attribute; if called from the same module as the
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attributes are being deprecated in, using the C{__name__} global can
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be helpful
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@type name: C{str}
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@param name: Attribute name to deprecate
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"""
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module = sys.modules[moduleName]
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if not isinstance(module, _ModuleProxy):
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module = _ModuleProxy(module)
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sys.modules[moduleName] = module
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_deprecateAttribute(module, name, version, message)
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def warnAboutFunction(offender, warningString):
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"""
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Issue a warning string, identifying C{offender} as the responsible code.
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This function is used to deprecate some behavior of a function. It differs
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from L{warnings.warn} in that it is not limited to deprecating the behavior
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of a function currently on the call stack.
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@param function: The function that is being deprecated.
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@param warningString: The string that should be emitted by this warning.
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@type warningString: C{str}
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@since: 11.0
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"""
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# inspect.getmodule() is attractive, but somewhat
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# broken in Python < 2.6. See Python bug 4845.
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offenderModule = sys.modules[offender.__module__]
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filename = inspect.getabsfile(offenderModule)
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lineStarts = list(findlinestarts(offender.__code__))
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lastLineNo = lineStarts[-1][1]
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globals = offender.__globals__
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kwargs = dict(
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category=DeprecationWarning,
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filename=filename,
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lineno=lastLineNo,
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module=offenderModule.__name__,
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registry=globals.setdefault("__warningregistry__", {}),
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module_globals=None)
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warn_explicit(warningString, **kwargs)
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def _passed(argspec, positional, keyword):
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"""
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Take an L{inspect.ArgSpec}, a tuple of positional arguments, and a dict of
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keyword arguments, and return a mapping of arguments that were actually
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passed to their passed values.
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@param argspec: The argument specification for the function to inspect.
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@type argspec: L{inspect.ArgSpec}
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@param positional: The positional arguments that were passed.
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@type positional: L{tuple}
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@param keyword: The keyword arguments that were passed.
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@type keyword: L{dict}
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@return: A dictionary mapping argument names (those declared in C{argspec})
|
|
to values that were passed explicitly by the user.
|
|
@rtype: L{dict} mapping L{str} to L{object}
|
|
"""
|
|
result = {}
|
|
unpassed = len(argspec.args) - len(positional)
|
|
if argspec.keywords is not None:
|
|
kwargs = result[argspec.keywords] = {}
|
|
if unpassed < 0:
|
|
if argspec.varargs is None:
|
|
raise TypeError("Too many arguments.")
|
|
else:
|
|
result[argspec.varargs] = positional[len(argspec.args):]
|
|
for name, value in zip(argspec.args, positional):
|
|
result[name] = value
|
|
for name, value in keyword.items():
|
|
if name in argspec.args:
|
|
if name in result:
|
|
raise TypeError("Already passed.")
|
|
result[name] = value
|
|
elif argspec.keywords is not None:
|
|
kwargs[name] = value
|
|
else:
|
|
raise TypeError("no such param")
|
|
return result
|
|
|
|
|
|
|
|
def _mutuallyExclusiveArguments(argumentPairs):
|
|
"""
|
|
Decorator which causes its decoratee to raise a L{TypeError} if two of the
|
|
given arguments are passed at the same time.
|
|
|
|
@param argumentPairs: pairs of argument identifiers, each pair indicating
|
|
an argument that may not be passed in conjunction with another.
|
|
@type argumentPairs: sequence of 2-sequences of L{str}
|
|
|
|
@return: A decorator, used like so::
|
|
|
|
@_mutuallyExclusiveArguments([["tweedledum", "tweedledee"]])
|
|
def function(tweedledum=1, tweedledee=2):
|
|
"Don't pass tweedledum and tweedledee at the same time."
|
|
|
|
@rtype: 1-argument callable taking a callable and returning a callable.
|
|
"""
|
|
def wrapper(wrappee):
|
|
argspec = inspect.getargspec(wrappee)
|
|
@wraps(wrappee)
|
|
def wrapped(*args, **kwargs):
|
|
arguments = _passed(argspec, args, kwargs)
|
|
for this, that in argumentPairs:
|
|
if this in arguments and that in arguments:
|
|
raise TypeError("nope")
|
|
return wrappee(*args, **kwargs)
|
|
return wrapped
|
|
return wrapper
|