Adjust ISet to have the same IRO under both legacy and C3.

Fixes a bunch of warnings importing this package with ZOPE_INTERFACE_LOG_CHANGED_IRO set.

.github/workflows/tests.yml

@@ -52,6 +52,7 @@ env:
   PYTHONDEVMODE: 1
   PYTHONFAULTHANDLER: 1
   ZOPE_INTERFACE_STRICT_IRO: 1
+  ZOPE_INTERFACE_LOG_CHANGED_IRO: 1
   # Require C extensions; this will be disabled later for
   # PyPy because zope.interface through at least 5.3
   # tries to import its C module even on PyPy with this, but

CHANGES.rst

@@ -41,6 +41,16 @@
   objects actually implemented such a method; instead, the boolean value
   is typically taken from ``__len__``.
 
+- Adjust the definition of ``ISet`` to produce the same resolution
+  order under the C3 and legacy orderings. This means that the legacy
+  order has changed slightly, but that this package emits no warnings
+  when ``ZOPE_INTERFACE_LOG_CHANGED_IRO=1``. Note that the legacy
+  order was not being used for these objects because the C3 ordering
+  was still consistent; it could only be obtained using
+  ``ZOPE_INTERFACE_USE_LEGACY_IRO=1``. See `PR 159
+  <https://github.com/zopefoundation/BTrees/pull/159>`_ for all the
+  interface updates.
+
 4.7.2 (2020-04-07)
 ==================
 

setup.py

@@ -169,7 +169,8 @@ def BTreeExtension(family):
     # 4.1.0 is the first version that PURE_PYTHON can run
     # ZODB tests
     'persistent >= 4.1.0',
-    'zope.interface',
+    # 5.0.0 added zope.interface.common.collections
+    'zope.interface >= 5.0.0',
 ]
 
 TESTS_REQUIRE = [

src/BTrees/Interfaces.py

@@ -111,7 +111,7 @@ def __getitem__(index):
         """
 
 
-class ISet(IKeySequence, ISetMutable):
+class ISet(ISetMutable, IKeySequence):
     def __and__(other):
         """Shortcut for :meth:`~BTrees.Interfaces.IMerge.intersection`"""
 

tox.ini

@@ -15,6 +15,7 @@ setenv =
     PYTHONFAULTHANDLER=1
     PYTHONDEVMODE=1
     ZOPE_INTERFACE_STRICT_IRO=1
+    ZOPE_INTERFACE_LOG_CHANGED_IRO=1
     PURE_PYTHON=0
     pure: PURE_PYTHON=1
     pypy: PURE_PYTHON=1