# -*- test-case-name: twisted.python.test.test_deprecate -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. """ Deprecation framework for Twisted. To mark a method, function, or class as being deprecated do this:: from incremental import Version from twisted.python.deprecate import deprecated @deprecated(Version("Twisted", 8, 0, 0)) def badAPI(self, first, second): ''' Docstring for badAPI. ''' ... @deprecated(Version("Twisted", 16, 0, 0)) class BadClass(object): ''' Docstring for BadClass. ''' The newly-decorated badAPI will issue a warning when called, and BadClass will issue a warning when instantiated. Both will also have a deprecation notice appended to their docstring. To deprecate properties you can use:: from incremental import Version from twisted.python.deprecate import deprecatedProperty class OtherwiseUndeprecatedClass(object): @deprecatedProperty(Version('Twisted', 16, 0, 0)) def badProperty(self): ''' Docstring for badProperty. ''' @badProperty.setter def badProperty(self, value): ''' Setter sill also raise the deprecation warning. ''' To mark module-level attributes as being deprecated you can use:: badAttribute = "someValue" ... deprecatedModuleAttribute( Version("Twisted", 8, 0, 0), "Use goodAttribute instead.", "your.full.module.name", "badAttribute") The deprecated attributes will issue a warning whenever they are accessed. If the attributes being deprecated are in the same module as the L{deprecatedModuleAttribute} call is being made from, the C{__name__} global can be used as the C{moduleName} parameter. See also L{incremental.Version}. @type DEPRECATION_WARNING_FORMAT: C{str} @var DEPRECATION_WARNING_FORMAT: The default deprecation warning string format to use when one is not provided by the user. """ from __future__ import division, absolute_import __all__ = [ 'deprecated', 'deprecatedProperty', 'getDeprecationWarningString', 'getWarningMethod', 'setWarningMethod', 'deprecatedModuleAttribute', ] import sys, inspect from warnings import warn, warn_explicit from dis import findlinestarts from functools import wraps from incremental import getVersionString from twisted.python.compat import _PY3 DEPRECATION_WARNING_FORMAT = '%(fqpn)s was deprecated in %(version)s' # Notionally, part of twisted.python.reflect, but defining it there causes a # cyclic dependency between this module and that module. Define it here, # instead, and let reflect import it to re-expose to the public. def _fullyQualifiedName(obj): """ Return the fully qualified name of a module, class, method or function. Classes and functions need to be module level ones to be correctly qualified. @rtype: C{str}. """ try: name = obj.__qualname__ except AttributeError: name = obj.__name__ if inspect.isclass(obj) or inspect.isfunction(obj): moduleName = obj.__module__ return "%s.%s" % (moduleName, name) elif inspect.ismethod(obj): try: cls = obj.im_class except AttributeError: # Python 3 eliminates im_class, substitutes __module__ and # __qualname__ to provide similar information. return "%s.%s" % (obj.__module__, obj.__qualname__) else: className = _fullyQualifiedName(cls) return "%s.%s" % (className, name) return name # Try to keep it looking like something in twisted.python.reflect. _fullyQualifiedName.__module__ = 'twisted.python.reflect' _fullyQualifiedName.__name__ = 'fullyQualifiedName' _fullyQualifiedName.__qualname__ = 'fullyQualifiedName' def _getReplacementString(replacement): """ Surround a replacement for a deprecated API with some polite text exhorting the user to consider it as an alternative. @type replacement: C{str} or callable @return: a string like "please use twisted.python.modules.getModule instead". """ if callable(replacement): replacement = _fullyQualifiedName(replacement) return "please use %s instead" % (replacement,) def _getDeprecationDocstring(version, replacement=None): """ Generate an addition to a deprecated object's docstring that explains its deprecation. @param version: the version it was deprecated. @type version: L{incremental.Version} @param replacement: The replacement, if specified. @type replacement: C{str} or callable @return: a string like "Deprecated in Twisted 27.2.0; please use twisted.timestream.tachyon.flux instead." """ doc = "Deprecated in %s" % (getVersionString(version),) if replacement: doc = "%s; %s" % (doc, _getReplacementString(replacement)) return doc + "." def _getDeprecationWarningString(fqpn, version, format=None, replacement=None): """ Return a string indicating that the Python name was deprecated in the given version. @param fqpn: Fully qualified Python name of the thing being deprecated @type fqpn: C{str} @param version: Version that C{fqpn} was deprecated in. @type version: L{incremental.Version} @param format: A user-provided format to interpolate warning values into, or L{DEPRECATION_WARNING_FORMAT } if L{None} is given. @type format: C{str} @param replacement: what should be used in place of C{fqpn}. Either pass in a string, which will be inserted into the warning message, or a callable, which will be expanded to its full import path. @type replacement: C{str} or callable @return: A textual description of the deprecation @rtype: C{str} """ if format is None: format = DEPRECATION_WARNING_FORMAT warningString = format % { 'fqpn': fqpn, 'version': getVersionString(version)} if replacement: warningString = "%s; %s" % ( warningString, _getReplacementString(replacement)) return warningString def getDeprecationWarningString(callableThing, version, format=None, replacement=None): """ Return a string indicating that the callable was deprecated in the given version. @type callableThing: C{callable} @param callableThing: Callable object to be deprecated @type version: L{incremental.Version} @param version: Version that C{callableThing} was deprecated in @type format: C{str} @param format: A user-provided format to interpolate warning values into, or L{DEPRECATION_WARNING_FORMAT } if L{None} is given @param callableThing: A callable to be deprecated. @param version: The L{incremental.Version} that the callable was deprecated in. @param replacement: what should be used in place of the callable. Either pass in a string, which will be inserted into the warning message, or a callable, which will be expanded to its full import path. @type replacement: C{str} or callable @return: A string describing the deprecation. @rtype: C{str} """ return _getDeprecationWarningString( _fullyQualifiedName(callableThing), version, format, replacement) def _appendToDocstring(thingWithDoc, textToAppend): """ Append the given text to the docstring of C{thingWithDoc}. If C{thingWithDoc} has no docstring, then the text just replaces the docstring. If it has a single-line docstring then it appends a blank line and the message text. If it has a multi-line docstring, then in appends a blank line a the message text, and also does the indentation correctly. """ if thingWithDoc.__doc__: docstringLines = thingWithDoc.__doc__.splitlines() else: docstringLines = [] if len(docstringLines) == 0: docstringLines.append(textToAppend) elif len(docstringLines) == 1: docstringLines.extend(['', textToAppend, '']) else: spaces = docstringLines.pop() docstringLines.extend(['', spaces + textToAppend, spaces]) thingWithDoc.__doc__ = '\n'.join(docstringLines) def deprecated(version, replacement=None): """ Return a decorator that marks callables as deprecated. To deprecate a property, see L{deprecatedProperty}. @type version: L{incremental.Version} @param version: The version in which the callable will be marked as having been deprecated. The decorated function will be annotated with this version, having it set as its C{deprecatedVersion} attribute. @param version: the version that the callable was deprecated in. @type version: L{incremental.Version} @param replacement: what should be used in place of the callable. Either pass in a string, which will be inserted into the warning message, or a callable, which will be expanded to its full import path. @type replacement: C{str} or callable """ def deprecationDecorator(function): """ Decorator that marks C{function} as deprecated. """ warningString = getDeprecationWarningString( function, version, None, replacement) @wraps(function) def deprecatedFunction(*args, **kwargs): warn( warningString, DeprecationWarning, stacklevel=2) return function(*args, **kwargs) _appendToDocstring(deprecatedFunction, _getDeprecationDocstring(version, replacement)) deprecatedFunction.deprecatedVersion = version return deprecatedFunction return deprecationDecorator def deprecatedProperty(version, replacement=None): """ Return a decorator that marks a property as deprecated. To deprecate a regular callable or class, see L{deprecated}. @type version: L{incremental.Version} @param version: The version in which the callable will be marked as having been deprecated. The decorated function will be annotated with this version, having it set as its C{deprecatedVersion} attribute. @param version: the version that the callable was deprecated in. @type version: L{incremental.Version} @param replacement: what should be used in place of the callable. Either pass in a string, which will be inserted into the warning message, or a callable, which will be expanded to its full import path. @type replacement: C{str} or callable @return: A new property with deprecated setter and getter. @rtype: C{property} @since: 16.1.0 """ class _DeprecatedProperty(property): """ Extension of the build-in property to allow deprecated setters. """ def _deprecatedWrapper(self, function): @wraps(function) def deprecatedFunction(*args, **kwargs): warn( self.warningString, DeprecationWarning, stacklevel=2) return function(*args, **kwargs) return deprecatedFunction def setter(self, function): return property.setter(self, self._deprecatedWrapper(function)) def deprecationDecorator(function): if _PY3: warningString = getDeprecationWarningString( function, version, None, replacement) else: # Because Python 2 sucks, we need to implement our own here -- lack # of __qualname__ means that we kinda have to stack walk. It maybe # probably works. Probably. -Amber functionName = function.__name__ className = inspect.stack()[1][3] # wow hax moduleName = function.__module__ fqdn = "%s.%s.%s" % (moduleName, className, functionName) warningString = _getDeprecationWarningString( fqdn, version, None, replacement) @wraps(function) def deprecatedFunction(*args, **kwargs): warn( warningString, DeprecationWarning, stacklevel=2) return function(*args, **kwargs) _appendToDocstring(deprecatedFunction, _getDeprecationDocstring(version, replacement)) deprecatedFunction.deprecatedVersion = version result = _DeprecatedProperty(deprecatedFunction) result.warningString = warningString return result return deprecationDecorator def getWarningMethod(): """ Return the warning method currently used to record deprecation warnings. """ return warn def setWarningMethod(newMethod): """ Set the warning method to use to record deprecation warnings. The callable should take message, category and stacklevel. The return value is ignored. """ global warn warn = newMethod class _InternalState(object): """ An L{_InternalState} is a helper object for a L{_ModuleProxy}, so that it can easily access its own attributes, bypassing its logic for delegating to another object that it's proxying for. @ivar proxy: a L{_ModuleProxy} """ def __init__(self, proxy): object.__setattr__(self, 'proxy', proxy) def __getattribute__(self, name): return object.__getattribute__(object.__getattribute__(self, 'proxy'), name) def __setattr__(self, name, value): return object.__setattr__(object.__getattribute__(self, 'proxy'), name, value) class _ModuleProxy(object): """ Python module wrapper to hook module-level attribute access. Access to deprecated attributes first checks L{_ModuleProxy._deprecatedAttributes}, if the attribute does not appear there then access falls through to L{_ModuleProxy._module}, the wrapped module object. @ivar _module: Module on which to hook attribute access. @type _module: C{module} @ivar _deprecatedAttributes: Mapping of attribute names to objects that retrieve the module attribute's original value. @type _deprecatedAttributes: C{dict} mapping C{str} to L{_DeprecatedAttribute} @ivar _lastWasPath: Heuristic guess as to whether warnings about this package should be ignored for the next call. If the last attribute access of this module was a C{getattr} of C{__path__}, we will assume that it was the import system doing it and we won't emit a warning for the next access, even if it is to a deprecated attribute. The CPython import system always tries to access C{__path__}, then the attribute itself, then the attribute itself again, in both successful and failed cases. @type _lastWasPath: C{bool} """ def __init__(self, module): state = _InternalState(self) state._module = module state._deprecatedAttributes = {} state._lastWasPath = False def __repr__(self): """ Get a string containing the type of the module proxy and a representation of the wrapped module object. """ state = _InternalState(self) return '<%s module=%r>' % (type(self).__name__, state._module) def __setattr__(self, name, value): """ Set an attribute on the wrapped module object. """ state = _InternalState(self) state._lastWasPath = False setattr(state._module, name, value) def __getattribute__(self, name): """ Get an attribute from the module object, possibly emitting a warning. If the specified name has been deprecated, then a warning is issued. (Unless certain obscure conditions are met; see L{_ModuleProxy._lastWasPath} for more information about what might quash such a warning.) """ state = _InternalState(self) if state._lastWasPath: deprecatedAttribute = None else: deprecatedAttribute = state._deprecatedAttributes.get(name) if deprecatedAttribute is not None: # If we have a _DeprecatedAttribute object from the earlier lookup, # allow it to issue the warning. value = deprecatedAttribute.get() else: # Otherwise, just retrieve the underlying value directly; it's not # deprecated, there's no warning to issue. value = getattr(state._module, name) if name == '__path__': state._lastWasPath = True else: state._lastWasPath = False return value class _DeprecatedAttribute(object): """ Wrapper for deprecated attributes. This is intended to be used by L{_ModuleProxy}. Calling L{_DeprecatedAttribute.get} will issue a warning and retrieve the underlying attribute's value. @type module: C{module} @ivar module: The original module instance containing this attribute @type fqpn: C{str} @ivar fqpn: Fully qualified Python name for the deprecated attribute @type version: L{incremental.Version} @ivar version: Version that the attribute was deprecated in @type message: C{str} @ivar message: Deprecation message """ def __init__(self, module, name, version, message): """ Initialise a deprecated name wrapper. """ self.module = module self.__name__ = name self.fqpn = module.__name__ + '.' + name self.version = version self.message = message def get(self): """ Get the underlying attribute value and issue a deprecation warning. """ # This might fail if the deprecated thing is a module inside a package. # In that case, don't emit the warning this time. The import system # will come back again when it's not an AttributeError and we can emit # the warning then. result = getattr(self.module, self.__name__) message = _getDeprecationWarningString(self.fqpn, self.version, DEPRECATION_WARNING_FORMAT + ': ' + self.message) warn(message, DeprecationWarning, stacklevel=3) return result def _deprecateAttribute(proxy, name, version, message): """ Mark a module-level attribute as being deprecated. @type proxy: L{_ModuleProxy} @param proxy: The module proxy instance proxying the deprecated attributes @type name: C{str} @param name: Attribute name @type version: L{incremental.Version} @param version: Version that the attribute was deprecated in @type message: C{str} @param message: Deprecation message """ _module = object.__getattribute__(proxy, '_module') attr = _DeprecatedAttribute(_module, name, version, message) # Add a deprecated attribute marker for this module's attribute. When this # attribute is accessed via _ModuleProxy a warning is emitted. _deprecatedAttributes = object.__getattribute__( proxy, '_deprecatedAttributes') _deprecatedAttributes[name] = attr def deprecatedModuleAttribute(version, message, moduleName, name): """ Declare a module-level attribute as being deprecated. @type version: L{incremental.Version} @param version: Version that the attribute was deprecated in @type message: C{str} @param message: Deprecation message @type moduleName: C{str} @param moduleName: Fully-qualified Python name of the module containing the deprecated attribute; if called from the same module as the attributes are being deprecated in, using the C{__name__} global can be helpful @type name: C{str} @param name: Attribute name to deprecate """ module = sys.modules[moduleName] if not isinstance(module, _ModuleProxy): module = _ModuleProxy(module) sys.modules[moduleName] = module _deprecateAttribute(module, name, version, message) def warnAboutFunction(offender, warningString): """ Issue a warning string, identifying C{offender} as the responsible code. This function is used to deprecate some behavior of a function. It differs from L{warnings.warn} in that it is not limited to deprecating the behavior of a function currently on the call stack. @param function: The function that is being deprecated. @param warningString: The string that should be emitted by this warning. @type warningString: C{str} @since: 11.0 """ # inspect.getmodule() is attractive, but somewhat # broken in Python < 2.6. See Python bug 4845. offenderModule = sys.modules[offender.__module__] filename = inspect.getabsfile(offenderModule) lineStarts = list(findlinestarts(offender.__code__)) lastLineNo = lineStarts[-1][1] globals = offender.__globals__ kwargs = dict( category=DeprecationWarning, filename=filename, lineno=lastLineNo, module=offenderModule.__name__, registry=globals.setdefault("__warningregistry__", {}), module_globals=None) warn_explicit(warningString, **kwargs) def _passedArgSpec(argspec, positional, keyword): """ Take an I{inspect.ArgSpec}, a tuple of positional arguments, and a dict of keyword arguments, and return a mapping of arguments that were actually passed to their passed values. @param argspec: The argument specification for the function to inspect. @type argspec: I{inspect.ArgSpec} @param positional: The positional arguments that were passed. @type positional: L{tuple} @param keyword: The keyword arguments that were passed. @type keyword: L{dict} @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 _passedSignature(signature, positional, keyword): """ Take an L{inspect.Signature}, a tuple of positional arguments, and a dict of keyword arguments, and return a mapping of arguments that were actually passed to their passed values. @param signature: The signature of the function to inspect. @type signature: L{inspect.Signature} @param positional: The positional arguments that were passed. @type positional: L{tuple} @param keyword: The keyword arguments that were passed. @type keyword: L{dict} @return: A dictionary mapping argument names (those declared in C{signature}) to values that were passed explicitly by the user. @rtype: L{dict} mapping L{str} to L{object} """ result = {} kwargs = None numPositional = 0 for (n, (name, param)) in enumerate(signature.parameters.items()): if param.kind == inspect.Parameter.VAR_POSITIONAL: # Varargs, for example: *args result[name] = positional[n:] numPositional = len(result[name]) + 1 elif param.kind == inspect.Parameter.VAR_KEYWORD: # Variable keyword args, for example: **my_kwargs kwargs = result[name] = {} elif param.kind in (inspect.Parameter.POSITIONAL_OR_KEYWORD, inspect.Parameter.POSITIONAL_ONLY): if n < len(positional): result[name] = positional[n] numPositional += 1 elif param.kind == inspect.Parameter.KEYWORD_ONLY: if name not in keyword: if param.default == inspect.Parameter.empty: raise TypeError("missing keyword arg {}".format(name)) else: result[name] = param.default else: raise TypeError("'{}' parameter is invalid kind: {}".format( name, param.kind)) if len(positional) > numPositional: raise TypeError("Too many arguments.") for name, value in keyword.items(): if name in signature.parameters.keys(): if name in result: raise TypeError("Already passed.") result[name] = value elif kwargs 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): if getattr(inspect, "signature", None): # Python 3 spec = inspect.signature(wrappee) _passed = _passedSignature else: # Python 2 spec = inspect.getargspec(wrappee) _passed = _passedArgSpec @wraps(wrappee) def wrapped(*args, **kwargs): arguments = _passed(spec, args, kwargs) for this, that in argumentPairs: if this in arguments and that in arguments: raise TypeError( ("The %r and %r arguments to %s " "are mutually exclusive.") % (this, that, _fullyQualifiedName(wrappee))) return wrappee(*args, **kwargs) return wrapped return wrapper