Added a utility for deprecating a module attribute
diff --git a/src/cryptography/utils.py b/src/cryptography/utils.py
index ac2f787..250e14b 100644
--- a/src/cryptography/utils.py
+++ b/src/cryptography/utils.py
@@ -7,12 +7,17 @@
import abc
import inspect
import sys
+import warnings
# DeprecatedIn07 objects exist. This comment exists to remind developers to
# look for them when it's time for the ninth release cycle deprecation dance.
+def read_only_property(name):
+ return property(lambda self: getattr(self, name))
+
+
def register_interface(iface):
def register_decorator(klass):
verify_interface(iface, klass)
@@ -21,10 +26,6 @@
return register_decorator
-def read_only_property(name):
- return property(lambda self: getattr(self, name))
-
-
class InterfaceNotImplemented(Exception):
pass
@@ -55,3 +56,36 @@
else:
def bit_length(x):
return len(bin(x)) - (2 + (x <= 0))
+
+
+class _DeprecatedValue(object):
+ def __init__(self, value, message, warning_class):
+ self.value = value
+ self.message = message
+ self.warning_class = warning_class
+
+
+class _ModuleWithDeprecations(object):
+ def __init__(self, module):
+ self.__dict__["_module"] = module
+
+ def __getattr__(self, attr):
+ obj = getattr(self._module, attr)
+ if isinstance(obj, _DeprecatedValue):
+ warnings.warn(obj.message, obj.warning_class, stacklevel=2)
+ obj = obj.value
+ return obj
+
+ def __setattr__(self, attr, value):
+ setattr(self._module, attr, value)
+
+ def __dir__(self):
+ return ["_module"] + dir(self._module)
+
+
+
+def deprecated(value, module_name, message, warning_class):
+ module = sys.modules[module_name]
+ if not isinstance(module, _ModuleWithDeprecations):
+ sys.modules[module_name] = module = _ModuleWithDeprecations(module)
+ return _DeprecatedValue(value, message, warning_class)