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.

6 files changed, 48 insertions, 14 deletions

diff --git a/src/zope/interface/common/__init__.py b/src/zope/interface/common/__init__.py
index acbc581..a8bedf0 100644
--- a/src/zope/interface/common/__init__.py
+++ b/src/zope/interface/common/__init__.py
@@ -121,19 +121,20 @@ class ABCInterfaceClass(InterfaceClass):
         # go ahead and give us a name to ease debugging.
         self.__name__ = name
         extra_classes = attrs.pop('extra_classes', ())
+        ignored_classes = attrs.pop('ignored_classes', ())
 
         if 'abc' not in attrs:
             # Something like ``IList(ISequence)``: We're extending
             # abc interfaces but not an ABC interface ourself.
-            self.__class__ = InterfaceClass
             InterfaceClass.__init__(self, name, bases, attrs)
-            for cls in extra_classes:
-                classImplements(cls, self)
+            ABCInterfaceClass.__register_classes(self, extra_classes, ignored_classes)
+            self.__class__ = InterfaceClass
             return
 
         based_on = attrs.pop('abc')
         self.__abc = based_on
         self.__extra_classes = tuple(extra_classes)
+        self.__ignored_classes = tuple(ignored_classes)
 
         assert name[1:] == based_on.__name__, (name, based_on)
         methods = {
@@ -216,11 +217,14 @@ class ABCInterfaceClass(InterfaceClass):
         method.positional = method.positional[1:]
         return method
 
-    def __register_classes(self):
+    def __register_classes(self, conformers=None, ignored_classes=None):
         # Make the concrete classes already present in our ABC's registry
         # declare that they implement this interface.
-
-        for cls in self.getRegisteredConformers():
+        conformers = conformers if conformers is not None else self.getRegisteredConformers()
+        ignored = ignored_classes if ignored_classes is not None else self.__ignored_classes
+        for cls in conformers:
+            if cls in ignored:
+                continue
             classImplements(cls, self)
 
     def getABC(self):
diff --git a/src/zope/interface/common/builtins.py b/src/zope/interface/common/builtins.py
index 9262340..a07c0a3 100644
--- a/src/zope/interface/common/builtins.py
+++ b/src/zope/interface/common/builtins.py
@@ -37,7 +37,6 @@ __all__ = [
 ]
 
 # pylint:disable=no-self-argument
-
 class IList(collections.IMutableSequence):
     """
     Interface for :class:`list`
diff --git a/src/zope/interface/common/collections.py b/src/zope/interface/common/collections.py
index 9731069..6c0496e 100644
--- a/src/zope/interface/common/collections.py
+++ b/src/zope/interface/common/collections.py
@@ -177,6 +177,10 @@ class ISequence(IReversible,
                 ICollection):
     abc = abc.Sequence
     extra_classes = (UserString,)
+    # On Python 2, basestring is registered as an ISequence, and
+    # its subclass str is an IByteString. If we also register str as
+    # an ISequence, that tends to lead to inconsistent resolution order.
+    ignored_classes = (basestring,) if str is bytes else () # pylint:disable=undefined-variable
 
     @optional
     def __reversed__():
diff --git a/src/zope/interface/common/mapping.py b/src/zope/interface/common/mapping.py
index 13fa317..de56cf8 100644
--- a/src/zope/interface/common/mapping.py
+++ b/src/zope/interface/common/mapping.py
@@ -43,7 +43,7 @@ class IItemMapping(Interface):
         """
 
 
-class IReadMapping(IItemMapping, collections.IContainer):
+class IReadMapping(collections.IContainer, IItemMapping):
     """
     Basic mapping interface.
 
@@ -72,7 +72,7 @@ class IWriteMapping(Interface):
         """Set a new item in the mapping."""
 
 
-class IEnumerableMapping(IReadMapping, collections.ISized):
+class IEnumerableMapping(collections.ISized, IReadMapping):
     """
     Mapping objects whose items can be enumerated.
 
@@ -171,7 +171,7 @@ class IExtendedWriteMapping(IWriteMapping):
 
 class IFullMapping(
         collections.IMutableMapping,
-        IExtendedReadMapping, IExtendedWriteMapping, IClonableMapping, IMapping):
+        IExtendedReadMapping, IExtendedWriteMapping, IClonableMapping, IMapping,):
     """
     Full mapping interface.
 
diff --git a/src/zope/interface/common/tests/__init__.py b/src/zope/interface/common/tests/__init__.py
index 059e46c..ade2bf3 100644
--- a/src/zope/interface/common/tests/__init__.py
+++ b/src/zope/interface/common/tests/__init__.py
@@ -38,7 +38,8 @@ def iter_abc_interfaces(predicate=lambda iface: True):
         if not predicate(iface):
             continue
 
-        registered = list(iface.getRegisteredConformers())
+        registered = set(iface.getRegisteredConformers())
+        registered -= set(iface._ABCInterfaceClass__ignored_classes)
         if registered:
             yield iface, registered
 
@@ -50,24 +51,46 @@ def add_abc_interface_tests(cls, module):
 
 
 def add_verify_tests(cls, iface_classes_iter):
+    cls.maxDiff = None
     for iface, registered_classes in iface_classes_iter:
         for stdlib_class in registered_classes:
-
             def test(self, stdlib_class=stdlib_class, iface=iface):
                 if stdlib_class in self.UNVERIFIABLE or stdlib_class.__name__ in self.UNVERIFIABLE:
                     self.skipTest("Unable to verify %s" % stdlib_class)
 
                 self.assertTrue(self.verify(iface, stdlib_class))
 
-            name = 'test_auto_' + stdlib_class.__name__ + '_' + iface.__name__
+            suffix = "%s_%s_%s" % (
+                stdlib_class.__name__,
+                iface.__module__.replace('.', '_'),
+                iface.__name__
+            )
+            name = 'test_auto_' + suffix
             test.__name__ = name
-            assert not hasattr(cls, name)
+            assert not hasattr(cls, name), (name, list(cls.__dict__))
             setattr(cls, name, test)
 
+            def test_ro(self, stdlib_class=stdlib_class, iface=iface):
+                from zope.interface import ro
+                from zope.interface import implementedBy
+                self.assertEqual(
+                    tuple(ro.ro(iface, strict=True)),
+                    iface.__sro__)
+                implements = implementedBy(stdlib_class)
+                strict = stdlib_class not in self.NON_STRICT_RO
+                self.assertEqual(
+                    tuple(ro.ro(implements, strict=strict)),
+                    implements.__sro__)
+
+            name = 'test_auto_ro_' + suffix
+            test_ro.__name__ = name
+            assert not hasattr(cls, name)
+            setattr(cls, name, test_ro)
 
 class VerifyClassMixin(unittest.TestCase):
     verifier = staticmethod(verifyClass)
     UNVERIFIABLE = ()
+    NON_STRICT_RO = ()
 
     def _adjust_object_before_verify(self, iface, x):
         return x
diff --git a/src/zope/interface/common/tests/test_collections.py b/src/zope/interface/common/tests/test_collections.py
index 32ab801..f06e12e 100644
--- a/src/zope/interface/common/tests/test_collections.py
+++ b/src/zope/interface/common/tests/test_collections.py
@@ -17,6 +17,7 @@ try:
 except ImportError:
     import collections as abc
 from collections import deque
+from collections import OrderedDict
 
 
 try:
@@ -118,6 +119,9 @@ class TestVerifyClass(VerifyClassMixin, unittest.TestCase):
             type({}.viewitems()),
             type({}.viewkeys()),
         })
+        NON_STRICT_RO = {
+            OrderedDict
+        }
 
 add_abc_interface_tests(TestVerifyClass, collections.ISet.__module__)