Use C3 (mostly) to compute IRO.issue21

Fixes #21

The 'mostly' is because interfaces are used in cases that C3 forbids;
when there's a conflict, we fallback to the legacy algorithm. It turns
out there are few conflicts (13K out of 149K total orderings in Plone).

I hoped the fix for #8 might shake out automatically, but it didn't.

Optimize the extremely common case of a __bases__ of length one.

In the benchmark, 4/5 of the interfaces and related objects have a base of length one.

Fix the bad IROs in the bundled ABC interfaces, and implement a way to get warnings or errors.

In running plone/buildout.coredev and tracking the RO requests, the
stats for equal, not equal, and inconsistent-so-fallback, I got
{'ros': 148868, 'eq': 138461, 'ne': 10407, 'inconsistent': 12934}

Add the interface module to the Attribute str.

This was extremely helpful tracking down the Plone problem; IDate is defined in multiple modules.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/zope/interface/interfaces.py b/src/zope/interface/interfaces.py
index 6ac235a..bf0d6c7 100644
--- a/src/zope/interface/interfaces.py
+++ b/src/zope/interface/interfaces.py
@@ -441,6 +441,11 @@ class IInterfaceDeclaration(Interface):
         instances of ``A`` and ``B`` provide.
         """
 
+    def classImplementsFirst(cls, interface):
+        """
+        See :func:`zope.interface.classImplementsFirst`.
+        """
+
     def implementer(*interfaces):
         """Create a decorator for declaring interfaces implemented by a factory.