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# -*- 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:
'''
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:
@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.
To mark an optional, keyword parameter of a function or method as deprecated
without deprecating the function itself, you can use::
@deprecatedKeywordParameter(Version("Twisted", 19, 2, 0), 'baz')
def someFunction(foo, bar=0, baz=None):
...
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.
"""
__all__ = [
"deprecated",
"deprecatedProperty",
"getDeprecationWarningString",
"getWarningMethod",
"setWarningMethod",
"deprecatedModuleAttribute",
"deprecatedKeywordParameter",
]
import inspect
import sys
from dis import findlinestarts
from functools import wraps
from types import ModuleType
from typing import Any, Callable, Dict, Optional, TypeVar, cast
from warnings import warn, warn_explicit
from incremental import Version, getVersionString
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 f"{moduleName}.{name}"
elif inspect.ismethod(obj):
return f"{obj.__module__}.{obj.__qualname__}"
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 f"please use {replacement} instead"
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 = f"Deprecated in {getVersionString(version)}"
if replacement:
doc = f"{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
<twisted.python.deprecate.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 = "{}; {}".format(
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
<twisted.python.deprecate.DEPRECATION_WARNING_FORMAT>} if L{None} is
given
@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 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 # type: ignore[attr-defined]
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 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, # type: ignore[attr-defined]
DeprecationWarning,
stacklevel=2,
)
return function(*args, **kwargs)
return deprecatedFunction
def setter(self, function):
return property.setter(self, self._deprecatedWrapper(function))
def deprecationDecorator(function):
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 # type: ignore[attr-defined]
result = _DeprecatedProperty(deprecatedFunction)
result.warningString = warningString # type: ignore[attr-defined]
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:
"""
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:
"""
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) -> str:
"""
Get a string containing the type of the module proxy and a
representation of the wrapped module object.
"""
state = _InternalState(self)
return f"<{type(self).__name__} module={state._module!r}>"
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:
"""
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 = cast(ModuleType, _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 offender: 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__]
warn_explicit(
warningString,
category=DeprecationWarning,
filename=inspect.getabsfile(offenderModule),
lineno=max(lineNumber for _, lineNumber in findlinestarts(offender.__code__)),
module=offenderModule.__name__,
registry=offender.__globals__.setdefault("__warningregistry__", {}),
module_globals=None,
)
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: Dict[str, object] = {}
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(f"missing keyword arg {name}")
else:
result[name] = param.default
else:
raise TypeError(f"'{name}' parameter is invalid kind: {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):
spec = inspect.signature(wrappee)
_passed = _passedSignature
@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
_Tc = TypeVar("_Tc", bound=Callable[..., Any])
def deprecatedKeywordParameter(
version: Version, name: str, replacement: Optional[str] = None
) -> Callable[[_Tc], _Tc]:
"""
Return a decorator that marks a keyword parameter of a callable
as deprecated. A warning will be emitted if a caller supplies
a value for the parameter, whether the caller uses a keyword or
positional syntax.
@type version: L{incremental.Version}
@param version: The version in which the parameter will be marked as
having been deprecated.
@type name: L{str}
@param name: The name of the deprecated parameter.
@type replacement: L{str}
@param replacement: Optional text indicating what should be used in
place of the deprecated parameter.
@since: Twisted 21.2.0
"""
def wrapper(wrappee: _Tc) -> _Tc:
warningString = _getDeprecationWarningString(
f"The {name!r} parameter to {_fullyQualifiedName(wrappee)}",
version,
replacement=replacement,
)
doc = "The {!r} parameter was deprecated in {}".format(
name,
getVersionString(version),
)
if replacement:
doc = doc + "; " + _getReplacementString(replacement)
doc += "."
params = inspect.signature(wrappee).parameters
if (
name in params
and params[name].kind == inspect.Parameter.POSITIONAL_OR_KEYWORD
):
parameterIndex = list(params).index(name)
def checkDeprecatedParameter(*args, **kwargs):
if len(args) > parameterIndex or name in kwargs:
warn(warningString, DeprecationWarning, stacklevel=2)
return wrappee(*args, **kwargs)
else:
def checkDeprecatedParameter(*args, **kwargs):
if name in kwargs:
warn(warningString, DeprecationWarning, stacklevel=2)
return wrappee(*args, **kwargs)
decorated = cast(_Tc, wraps(wrappee)(checkDeprecatedParameter))
_appendToDocstring(decorated, doc)
return decorated
return wrapper
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