Fixes and changes since PyProtocols 0.9.3 release candidate 1
Fixes and changes since PyProtocols 0.9.2
Adapter factories are now only called with one argument: the object to
adapt. For backward compatibility, any adapter factories that require
more than one argument are wrapped in a converter. It's highly recommended
that you transition to one-argument adapters as soon as practical, since
using two-argument adapters will cause deprecation warnings in PyProtocols
version 1.0 (and causes PendingDeprecationWarnings in 0.9.3). This change
was made for symmetry with Zope and Twisted adapters, as well as Pythonic
adapter factories like int et al. The factory parameter to adapt() is DEPRECATED. An informal survey of
PyProtocols' users indicated that nobody was using it to any significant
degree, and its removal was unopposed. This feature was an extension to
PEP 246, so this brings PyProtocols into closer conformance with the PEP.
If you are currently using it, you will receive a DeprecationWarning, and
in PyProtocols 1.0 your code will break. Fixed protocols.sequenceOf() being unable to directly imply a non-sequence
protocol. Raise AdaptationFailure instead of NotImplementedError when adaptation
is unsuccessful. AdaptationFailure is a subclass of both TypeError and
NotImplementedError, so code written according to either PEP 246 or older
versions of PyProtocols will still catch the error. There is now an AbstractBase class, similar to Interface, that can be
used for the "ABC" (Abstract Base Class) style of interface usage, where the
interface may contain implementation code, and can be subclassed to create
concrete implementations. In previous versions, you could use Interface
as such a base class, but now calling an Interface object performs
adaptation rather than instantiation, unless the subclass redefines
__init__. Protocol instances (except for AbstractBase subclasses) are now callable
with a signature similar to adapt(). E.g. 'ISomething(foo,args)' is
equivalent to 'adapt(foo,ISomething,args)'. This convenient API, pioneered
by Twisted and later adopted by Zope X3, is now available in PyProtocols as
well. (Note that as a result of this change, the PyProtocols test suite now
requires a Zope X3 alpha release or better.)
setup.py now accepts a --without-speedups global option to disable
the C speedups module.
We now support the latest adapter_hooks protocol provided by Zope X3
interfaces, allowing multiple interface registry systems to participate
in Zope interfaces' __adapt__() implementation. Declaring an adapter from an instance to a protocol that was part
of a circular implication path resulted in infinite recursion.
Correcting the problem required a change in the return signature
of the declareProvides() method in the IOpenProvider interface.
Please see the docstring or the updated reference manual for details.
Thanks to Bob Ippolito for discovering the problem and bringing it to my
attention. Defining an adapter from one protocol to another, when that adapter does not
shorten the adaptation path, would produce a spurious KeyError.
Fixes since PyProtocols 0.9.1
Fixes and Enhancements since PyProtocols 0.9
Added the factoryMethod and equivalentProtocols keywords to advise(). Added sequenceOf(), allowing you to easily create a protocol
that represents a sequence of some base protocol, and automatically adapt
basic sequences (e.g. lists and tuples) to a "sequence of" the base
protocol, as long as all members of the input sequence can be adapted to the
base protocol. By default, only lists and tuples are considered to support
IBasicSequence. Added protocolForType() and protocolForURI(), that allow you
to link interfaces by intended semantics, not just by having identical
instances. For example, you can use protocolForType(file,["read"]) to
symbolize a file-like object with a read() method, or
protocolForURI("some UUID") to symbolize some documented interface. In addition to compact declarations, this also allows a module to refer to
an interface without importing a specific definition of it. Then, when that
module is used in a larger program, the linkage between the symbolic and
actual forms of the interface can be accomplished semi-automatically.
Enhanced Zope 3 support: Now, adapters can be registered between Zope
interfaces, and any types or instances. Note, however, that
interface-to-interface adaptation may not work if a class only declares what
it implements using the Zope interface API. This limitation might be able
to be removed later. Zope interfaces can now pass a much larger segment of
the test suite than before. Added 'protocols.Variation(baseProtocol,context=None)'; this
implements the LocalProtocol example in the documentation. Added Adapter and StickyAdapter convenience base classes. Adapter
offers a ready-made __init__() method suitable for most adapter
classes, while StickyAdapter instances automatically declare themselves as
an instance-specific adapter for any object they're used on. Thus, a
StickyAdapter can maintain its state across adapt() calls for the same
object, so long as the object can have instance-specific adapters declared.
(See "Protocol Declarations for Individual Objects" in the reference manual
for more information on this.) Added experimental support for 'ExtensionClass'; previously, PyProtocols
could raise bizarre errors and/or behave strangely when adapt() was called
on ExtensionClass instances. Fixed some problems with the test suite when running under Python 2.3.
PyProtocols itself worked fine, but the test suite was bitten by two minor
semantic changes that took effect in 2.3, resulting in lots of error
messages about ModuleType needing a parameter, and a test failure for
checkClassInfo in the FrameInfoTest test class. Fixed a memory leak in the C "speedups" module that leaked unbound
__conform__ and __adapt__ methods, as well as __class__ and __mro__
references. Also, fixed the C code potentially reraising invalid error
tracebacks under certain circumstances.
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