directly-instantiated types are unsupported in mypy-zope

[jaraco]

In Shoobx/mypy-zope#21, I learned that mypy-zope doesn't support direct invocation of an InterfaceClass such as seen here in foolscap. With Shoobx/mypy-zope#24, however, it will support the more typical metaclass syntax. Perhaps the best approach here may be to use the appropriate metaclass instantiation, something like

class RemoteInterface(metaclass=RemoteInterfaceClass): ...

(and an equivalent for Python 2).

[jaraco]

I've drafted a fix, but it unfortunately doesn't work as intended. It works on Python 3, but on Python 2, the test suite fails with 23 errors similar to:

Traceback (most recent call last):
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/twisted/trial/runner.py", line 531, in loadPackage
    module = modinfo.load()
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/twisted/python/modules.py", line 392, in load
    return self.pathEntry.pythonPath.moduleLoader(self.name)
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/twisted/python/reflect.py", line 308, in namedAny
    topLevelPackage = _importAndCheckStack(trialname)
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/twisted/python/reflect.py", line 247, in _importAndCheckStack
    return __import__(importName)
  File "/Users/jaraco/code/public/foolscap/src/foolscap/test/test__versions.py", line 9, in <module>
    from foolscap.api import __version__
  File "/Users/jaraco/code/public/foolscap/src/foolscap/api.py", line 16, in <module>
    from foolscap.pb import Tub
  File "/Users/jaraco/code/public/foolscap/src/foolscap/pb.py", line 14, in <module>
    from foolscap import ipb, base32, negotiate, broker, eventual, storage
  File "/Users/jaraco/code/public/foolscap/src/foolscap/negotiate.py", line 10, in <module>
    from foolscap import broker, referenceable, vocab
  File "/Users/jaraco/code/public/foolscap/src/foolscap/broker.py", line 17, in <module>
    from foolscap import call, slicer, referenceable, copyable, remoteinterface
  File "/Users/jaraco/code/public/foolscap/src/foolscap/call.py", line 11, in <module>
    from foolscap.logging import log
  File "/Users/jaraco/code/public/foolscap/src/foolscap/logging/log.py", line 9, in <module>
    from foolscap.logging.interfaces import IIncidentReporter
  File "/Users/jaraco/code/public/foolscap/src/foolscap/logging/interfaces.py", line 3, in <module>
    from foolscap.remoteinterface import RemoteInterface
  File "/Users/jaraco/code/public/foolscap/src/foolscap/remoteinterface.py", line 416, in <module>
    """)
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/six.py", line 719, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
    
  File "<string>", line 1, in <module>
    
  File "/Users/jaraco/code/public/foolscap/src/foolscap/remoteinterface.py", line 39, in __init__
    rname, remote_attrs = self._parseRemoteInterface(iname, attrs)
  File "/Users/jaraco/code/public/foolscap/src/foolscap/remoteinterface.py", line 77, in _parseRemoteInterface
    IConstraint.providedBy(attrs[name]))]
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/zope/interface/declarations.py", line 394, in implementedBy
    spec_name = _implements_name(cls)
  File "/Users/jaraco/code/public/foolscap/.tox/py27/lib/python2.7/site-packages/zope/interface/declarations.py", line 292, in _implements_name
    '.' + (getattr(ob, '__name__', '?') or '?')
exceptions.TypeError: unsupported operand type(s) for +: 'property' and 'str'

[jaraco]

I was able to work around the issue by deriving the RemoteInterface from Interface and removing __metaclass__ from the class dict on construction (4100bdf).