diff options
Diffstat (limited to 'src/zope/interface/declarations.py')
| -rw-r--r-- | src/zope/interface/declarations.py | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/src/zope/interface/declarations.py b/src/zope/interface/declarations.py index 9a0146c..d687599 100644 --- a/src/zope/interface/declarations.py +++ b/src/zope/interface/declarations.py @@ -131,6 +131,19 @@ class Declaration(Specification): __radd__ = __add__ + @staticmethod + def _add_interfaces_to_cls(interfaces, cls): + # Strip redundant interfaces already provided + # by the cls so we don't produce invalid + # resolution orders. + implemented_by_cls = implementedBy(cls) + interfaces = tuple([ + iface + for iface in interfaces + if not implemented_by_cls.isOrExtends(iface) + ]) + return interfaces + (implemented_by_cls,) + class _ImmutableDeclaration(Declaration): # A Declaration that is immutable. Used as a singleton to @@ -747,7 +760,7 @@ class Provides(Declaration): # Really named ProvidesClass def __init__(self, cls, *interfaces): self.__args = (cls, ) + interfaces self._cls = cls - Declaration.__init__(self, *(interfaces + (implementedBy(cls), ))) + Declaration.__init__(self, *self._add_interfaces_to_cls(interfaces, cls)) def __repr__(self): return "<%s.%s for %s>" % ( @@ -890,7 +903,7 @@ class ClassProvides(Declaration, ClassProvidesBase): self._cls = cls self._implements = implementedBy(cls) self.__args = (cls, metacls, ) + interfaces - Declaration.__init__(self, *(interfaces + (implementedBy(metacls), ))) + Declaration.__init__(self, *self._add_interfaces_to_cls(interfaces, metacls)) def __repr__(self): return "<%s.%s for %s>" % ( |