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Release Notes
=============
Version 1.10.5
--------------
**Bugs Fixed**
* Post import hook discovery was not working correctly where multiple
target modules were registered in the same entry point list. Only the
callback for the last would be called regardless of the target module.
* If a ``WeakFunctionProxy`` wrapper was used around a method of a class
which was decorated using a wrapt decorator, the decorator wasn't being
invoked when the method was called via the weakref proxy.
**Features Changed**
* The ``register_post_import_hook()`` function, modelled after the
function of the same name in PEP-369 has been extended to allow a string
name to be supplied for the import hook. This needs to be of the form
``module::function`` and will result in an import hook proxy being used
which will only load and call the function of the specified moduled when
the import hook is required. This avoids needing to load the code needed
to operate on the target module unless required.
Version 1.10.4
--------------
**Bugs Fixed**
* Fixup botched package version number from 1.10.3 release.
Version 1.10.3
--------------
**Bugs Fixed**
* Post import hook discovery from third party modules declared via
``setuptools`` entry points was failing due to typo in temporary variable
name. Also added the ``discover_post_import_hooks()`` to the public API
as was missing.
**Features Changed**
* To ensure parity between pure Python and C extension variants of the
``ObjectProxy`` class, allow the ``__wrapped__`` attribute to be set
in a derived class when the ``ObjectProxy.__init__()`` method hasn't
been called.
Version 1.10.2
--------------
**Bugs Fixed**
* When creating a derived ``ObjectProxy``, if the base class ``__init__()``
method wasn't called and the the ``__wrapped__`` attribute was accessed,
in the pure Python implementation a recursive call of ``__getattr__()``
would occur and the maximum stack depth would be reached and an exception
raised.
* When creating a derived ``ObjectProxy``, if the base class ``__init__()``
method wasn't called, in the C extension implementation, if that instance
was then used in a binary arithmetic operation the process would crash.
Version 1.10.1
--------------
**Bugs Fixed**
* When using ``FunctionWrapper`` around a method of an existing instance of
a class, rather than on the type, then a memory leak could occur in two
different scenarios.
The first issue was that wrapping a method on an instance of a class was
causing an unwanted reference to the class meaning that if the class type
was transient, such as it is being created inside of a function call, the
type object would leak.
The second issue was that wrapping a method on an instance of a class and
then calling the method was causing an unwanted reference to the instance
meaning that if the instance was transient, it would leak.
This was only occuring when the C extension component for the
``wrapt`` module was being used.
Version 1.10.0
--------------
**New Features**
* When specifying an adapter for a decorator, it is now possible to pass
in, in addition to passing in a callable, a tuple of the form which
is returned by ``inspect.getargspec()``, or a string of the form which
is returned by ``inspect.formatargspec()``. In these two cases the
decorator will automatically compile a stub function to use as the
adapter. This eliminates the need for a caller to generate the stub
function if generating the signature on the fly.
::
def argspec_factory(wrapped):
argspec = inspect.getargspec(wrapped)
args = argspec.args[1:]
defaults = argspec.defaults and argspec.defaults[-len(argspec.args):]
return inspect.ArgSpec(args, argspec.varargs,
argspec.keywords, defaults)
def session(wrapped):
@wrapt.decorator(adapter=argspec_factory(wrapped))
def _session(wrapped, instance, args, kwargs):
with transaction() as session:
return wrapped(session, *args, **kwargs)
return _session(wrapped)
This mechanism and the original mechanism to pass a function, meant
that the adapter function had to be created in advance. If the adapter
needed to be generated on demand for the specific function to be
wrapped, then it would have been necessary to use a closure around
the definition of the decorator as above, such that the generator could
be passed in.
As a convenience, instead of using such a closure, it is also now
possible to write:
::
def argspec_factory(wrapped):
argspec = inspect.getargspec(wrapped)
args = argspec.args[1:]
defaults = argspec.defaults and argspec.defaults[-len(argspec.args):]
return inspect.ArgSpec(args, argspec.varargs,
argspec.keywords, defaults)
@wrapt.decorator(adapter=wrapt.adapter_factory(argspec_factory))
def _session(wrapped, instance, args, kwargs):
with transaction() as session:
return wrapped(session, *args, **kwargs)
The result of ``wrapt.adapter_factory()`` will be recognised as indicating
that the creation of the adapter is to be deferred until the decorator is
being applied to a function. The factory function for generating the
adapter function or specification on demand will be passed the function
being wrapped by the decorator.
If wishing to create a library of routines for generating adapter
functions or specifications dynamically, then you can do so by creating
classes which derive from ``wrapt.AdapterFactory`` as that is the type
which is recognised as indicating lazy evaluation of the adapter
function. For example, ``wrapt.adapter_factory()`` is itself implemented
as:
::
class DelegatedAdapterFactory(wrapt.AdapterFactory):
def __init__(self, factory):
super(DelegatedAdapterFactory, self).__init__()
self.factory = factory
def __call__(self, wrapped):
return self.factory(wrapped)
adapter_factory = DelegatedAdapterFactory
**Bugs Fixed**
* The ``inspect.signature()`` function was only added in Python 3.3.
Use fallback when doesn't exist and on Python 3.2 or earlier Python 3
versions.
Note that testing is only performed for Python 3.3+, so it isn't
actually known if the ``wrapt`` package works on Python 3.2.
Version 1.9.0
-------------
**Features Changed**
* When using ``wrapt.wrap_object()``, it is now possible to pass an
arbitrary object in addition to a module object, or a string name
identifying a module. Similar for underlying ``wrapt.resolve_path()``
function.
**Bugs Fixed**
* It is necessary to proxy the special ``__weakref__`` attribute in the
pure Python object proxy else using ``inspect.getmembers()`` on a
decorator class will fail.
* The ``FunctionWrapper`` class was not passing through the instance
correctly to the wrapper function when it was applied to a method of an
existing instance of a class.
* The ``FunctionWrapper`` was not always working when applied around a
method of a class type by accessing the method to be wrapped using
``getattr()``. Instead it is necessary to access the original unbound
method from the class ``__dict__``. Updated the ``FunctionWrapper`` to
work better in such situations, but also modify ``resolve_path()`` to
always grab the class method from the class ``__dict__`` when wrapping
methods using ``wrapt.wrap_object()`` so wrapping is more predictable.
When doing monkey patching ``wrapt.wrap_object()`` should always be
used to ensure correct operation.
* The ``AttributeWrapper`` class used internally to the function
``wrap_object_attribute()`` had wrongly named the ``__delete__`` method
for the descriptor as ``__del__``.
Version 1.8.0
-------------
**Features Changed**
* Previously using @wrapt.decorator on a class type didn't really yield
anything which was practically useful. This is now changed and when
applied to a class an instance of the class will be automatically
created to be used as the decorator wrapper function. The requirement
for this is that the __call__() method be specified in the style as
would be done for the decorator wrapper function.
::
@wrapt.decorator
class mydecoratorclass(object):
def __init__(self, arg=None):
self.arg = arg
def __call__(self, wrapped, instance, args, kwargs):
return wrapped(*args, **kwargs)
@mydecoratorclass
def function():
pass
If the resulting decorator class is to be used with no arguments, the
__init__() method of the class must have all default arguments. These
arguments can be optionally supplied though, by using keyword arguments
to the resulting decorator when applied to the function to be decorated.
::
@mydecoratorclass(arg=1)
def function():
pass
Version 1.7.0
-------------
**New Features**
* Provide wrapt.getcallargs() for determining how arguments mapped to a
wrapped function. For Python 2.7 this is actually inspect.getcallargs()
with a local copy being used in the case of Python 2.6.
* Added wrapt.wrap_object_attribute() as a way of wrapping or otherwise
modifying the result of trying to access the attribute of an object
instance. It works by adding a data descriptor with the same name as
the attribute, to the class type, allowing reading of the attribute
to be intercepted. It does not affect updates to or deletion of the
attribute.
**Bugs Fixed**
* Need to explicitly proxy special methods __bytes__(), __reversed__()
and __round__() as they are only looked up on the class type and not
the instance, so can't rely on __getattr__() fallback.
* Raise more appropriate TypeError, with corresponding message, rather
than IndexError, when a decorated instance or class method is called via
the class but the required 1st argument of the instance or class is not
supplied.
Version 1.6.0
-------------
**Bugs Fixed**
* The ObjectProxy class would return that the __call__() method existed
even though the wrapped object didn't have one. Similarly, callable()
would always return True even if the wrapped object was not callable.
This resulted due to the existance of the __call__() method on the
wrapper, required to support the possibility that the wrapped object
may be called via the proxy object even if it may not turn out that
the wrapped object was callable.
Because checking for the existance of a __call__() method or using
callable() can sometimes be used to indirectly infer the type of an
object, this could cause issues. To ensure that this now doesn't
occur, the ability to call a wrapped object via the proxy object has
been removed from ObjectProxy. Instead, a new class CallableObjectProxy
is now provided, with it being necessary to make a conscious choice as
to which should be used based on whether the object to be wrapped is
in fact callable.
Note that neither before this change, or with the introduction of the
class CallableObjectProxy, does the object proxy perform binding. If
binding behaviour is required it still needs to be implemented
explicitly to match the specific requirements of the use case.
Alternatively, the FunctionWrapper class should be used which does
implement binding, but also enforces a wrapper mechanism for
manipulating what happens at the time of the call.
Version 1.5.1
-------------
**Bugs Fixed**
* Instance method locking for the synchronized decorator was not correctly
locking on the instance but the class, if a synchronized class method
had been called prior to the synchronized instance method.
Version 1.5.0
-------------
**New Features**
* Enhanced @wrapt.transient_function_wrapper so it can be applied to
instance methods and class methods with the self/cls argument being
supplied correctly. This allows instance and class methods to be used for
this type of decorator, with the instance or class type being able to
be used to hold any state required for the decorator.
**Bugs Fixed**
* If the wrong details for a function to be patched was given to the
decorator @wrapt.transient_function_wrapper, the exception indicating
this was being incorrectly swallowed up and mutating to a different
more obscure error about local variable being access before being set.
Version 1.4.2
-------------
**Bugs Fixed**
* A process could crash if the C extension module was used and when using
the ObjectProxy class a reference count cycle was created that required
the Python garbage collector to kick in to break the cycle. This was
occuring as the C extension had not implemented GC support in the
ObjectProxy class correctly.
Version 1.4.1
-------------
**Bugs Fixed**
* Overriding __wrapped__ attribute directly on any wrapper more than once
could cause corruption of memory due to incorrect reference count
decrement.
Version 1.4.0
-------------
**New Features**
* Enhanced @wrapt.decorator and @wrapt.function_wrapper so they can be
applied to instance methods and class methods with the self/cls argument
being supplied correctly. This allows instance and class methods to be
used as decorators, with the instance or class type being able to be used
to hold any state required for the decorator.
**Bugs Fixed**
* Fixed process crash in extension when the wrapped object passed as first
argument to FunctionWrapper did not have a tp_descr_get callback for the
type at C code level. Now raised an AttributeError exception in line with
what Python implementation does.
Version 1.3.1
-------------
**Bugs Fixed**
* The discover_post_import_hooks() function had not been added to the
top level wrapt module.
Version 1.3.0
-------------
**New Features**
* Added a @transient_function_wrapper decorator for applying a wrapper
function around a target function only for the life of a single function
call. The decorator is useful for performing mocking or pass through
data validation/modification when doing unit testing of packages.
Version 1.2.1
-------------
**Bugs Fixed**
* In C implementation, not dealing with unbound method type creation
properly which would cause later problems when calling instance method
via the class type in certain circumstances. Introduced problem in 1.2.0.
* Eliminated compiler warnings due to missing casts in C implementation.
Version 1.2.0
-------------
**New Features**
* Added an 'enabled' option to @decorator and FunctionWrapper which can
be provided a boolean, or a function returning a boolean to allow the
work of the decorator to be disabled dynamically. When a boolean, is
used for @decorator, the wrapper will not even be applied if 'enabled'
is False. If a function, then will be called prior to wrapper being
called and if returns False, then original wrapped function called
directly rather than the wrapper being called.
* Added in an implementation of a post import hook mechanism in line with
that described in PEP 369.
* Added in helper functions specifically designed to assist in performing
monkey patching of existing code.
**Features Changed**
* Collapsed functionality of _BoundMethodWrapper into _BoundFunctionWrapper
and renamed the latter to BoundFunctionWrapper. If deriving from the
FunctionWrapper class and needing to override the type of the bound
wrapper, the class attribute ``__bound_function_wrapper__`` should be set
in the derived FunctionWrapper class to the replacement type.
**Bugs Fixed**
* When creating a custom proxy by deriving from ObjectProxy and the custom
proxy needed to override __getattr__(), it was not possible to called the
base class ObjectProxy.__getattr__() when the C implementation of
ObjectProxy was being used. The derived class __getattr__() could also
get ignored.
* Using inspect.getargspec() now works correctly on bound methods when an
adapter function can be provided to @decorator.
Version 1.1.3
-------------
**New Features**
* Added a _self_parent attribute to FunctionWrapper and bound variants.
For the FunctionWrapper the value will always be None. In the case of the
bound variants of the function wrapper, the attribute will refer back
to the unbound FunctionWrapper instance. This can be used to get a back
reference to the parent to access or cache data against the persistent
function wrapper, the bound wrappers often being transient and only
existing for the single call.
**Improvements**
* Use interned strings to optimise name comparisons in the setattro()
method of the C implementation of the object proxy.
**Bugs Fixed**
* The pypy interpreter is missing operator.__index__() so proxying of that
method in the object proxy would fail. This is a bug in pypy which is
being addressed. Use operator.index() instead which pypy does provide
and which also exists for CPython.
* The pure Python implementation allowed the __wrapped__ attribute to be
deleted which could cause problems. Now raise a TypeError exception.
* The C implementation of the object proxy would crash if an attempt was
made to delete the __wrapped__ attribute from the object proxy. Now raise a
TypeError exception.
Version 1.1.2
-------------
**Improvements**
* Reduced performance overhead from previous versions. Most notable in the
C implementation. Benchmark figures have been updated in documentation.
Version 1.1.1
-------------
**Bugs Fixed**
* Python object memory leak was occuring due to incorrect increment of
object reference count in C implementation of object proxy when an
instance method was called via the class and the instance passed in
explicitly.
* In place operators in pure Python object proxy for __idiv__ and
__itruediv__ were not replacing the wrapped object with the result
of the operation on the wrapped object.
* In place operators in C implementation of Python object proxy were
not replacing the wrapped object with the result of the operation on the
wrapped object.
Version 1.1.0
-------------
**New Features**
* Added a synchronized decorator for performing thread mutex locking on
functions, object instances or classes. This is the same decorator as
covered as an example in the wrapt documentation.
* Added a WeakFunctionProxy class which can wrap references to instance
methods as well as normal functions.
* Exposed from the C extension the classes _FunctionWrapperBase,
_BoundFunctionWrapper and _BoundMethodWrapper so that it is possible to
create new variants of FunctionWrapper in pure Python code.
**Bugs Fixed**
* When deriving from ObjectProxy, and the C extension variant
was being used, if a derived class overrode __new__() and tried to access
attributes of the ObjectProxy created using the base class __new__()
before __init__() was called, then an exception would be raised
indicating that the 'wrapper has not been initialised'.
* When deriving from ObjectProxy, and the C extension variant
was being used, if a derived class __init__() attempted to update
attributes, even the special '_self_' attributed before calling the base
class __init__() methid, then an exception would be raised indicating
that the 'wrapper has not been initialised'.
Version 1.0.0
-------------
Initial release.