thirdparty: vendor zope.interface 4.4.3 I've been trying to formalize interfaces for various components of Mercurial. So far, we've been using the "abc" package. This package is "good enough" for a lot of tasks. But it quickly falls over. For example, if you declare an @abc.abstractproperty, you must implement that attribute with a @property or the class compile time checking performed by abc will complain. This often forces you to implement dumb @property wrappers to return a _ prefixed attribute of the sane name. That's ugly. I've also wanted to implement automated checking that classes conform to various interfaces and don't expose other "public" attributes. After doing a bit of research and asking around, the general consensus seems to be that zope.interface is the best package for doing interface-based programming in Python. It has built-in support for verifying classes and objects conform to interfaces. It allows an interface's properties to be defined during __init__. There's even an "adapter registry" that allow you to register interfaces and look up which classes implement them. That could potentially be useful for places where our custom registry.py modules currently facilitates central registrations, but at a type level. Imagine extensions providing alternate implementations of things like the local repository interface to allow opening repositories with custom requirements. Anyway, this commit vendors zope.interface 4.4.3. The contents of the source tarball have been copied into mercurial/thirdparty/zope/ without modifications. Test modules have been removed because they are not interesting to us. The LICENSE.txt file has been copied so it lives next to the source. The Python modules don't use relative imports. zope/__init__.py defines a namespace package. So we'll need to modify the source code before this package is usable inside Mercurial. This will be done in subsequent commits. # no-check-commit for various style failures Differential Revision: https://phab.mercurial-scm.org/D2928