From b1807049d47afef711c467b785fae6aab7be851a Mon Sep 17 00:00:00 2001
From: Jason Madden <jamadden@gmail.com>
Date: Tue, 7 Apr 2020 07:04:44 -0500
Subject: Feedback from review: whitespace, doc clarification, and a unit test
 showing the precedence of __conform__ vs __adapt__.

---
 src/zope/interface/common/__init__.py      |  2 +-
 src/zope/interface/interface.py            |  5 +++-
 src/zope/interface/interfaces.py           | 30 +++++++++++------------
 src/zope/interface/tests/test_interface.py | 39 +++++++++++++++++++++++++++++-
 4 files changed, 58 insertions(+), 18 deletions(-)

(limited to 'src/zope/interface')

diff --git a/src/zope/interface/common/__init__.py b/src/zope/interface/common/__init__.py
index b40c317..01f0bd3 100644
--- a/src/zope/interface/common/__init__.py
+++ b/src/zope/interface/common/__init__.py
@@ -259,5 +259,5 @@ class ABCInterfaceClass(InterfaceClass):
         return set(itertools.chain(registered, self.__extra_classes))
 
 
-ABCInterface = ABCInterfaceClass.__new__(ABCInterfaceClass, 'ABCInterfaceClass', (), {})
+ABCInterface = ABCInterfaceClass.__new__(ABCInterfaceClass, 'ABCInterface', (), {})
 InterfaceClass.__init__(ABCInterface, 'ABCInterface', (Interface,), {})
diff --git a/src/zope/interface/interface.py b/src/zope/interface/interface.py
index ff26d33..f819441 100644
--- a/src/zope/interface/interface.py
+++ b/src/zope/interface/interface.py
@@ -662,7 +662,10 @@ def interfacemethod(func):
     This is a decorator that functions like `staticmethod` et al.
 
     The primary use of this decorator is to allow interface definitions to
-    define the ``__adapt__`` method.
+    define the ``__adapt__`` method, but other interface methods can be
+    overridden this way too.
+
+    .. seealso:: `zope.interface.interfaces.IInterfaceDeclaration.interfacemethod`
     """
     f_locals = sys._getframe(1).f_locals
     methods = f_locals.setdefault(INTERFACE_METHODS, {})
diff --git a/src/zope/interface/interfaces.py b/src/zope/interface/interfaces.py
index 6321d0c..9334374 100644
--- a/src/zope/interface/interfaces.py
+++ b/src/zope/interface/interfaces.py
@@ -490,7 +490,7 @@ class IInterfaceDeclaration(Interface):
         This is a way of executing :meth:`IElement.setTaggedValue` from
         the definition of the interface. For example::
 
-            class IFoo(Interface):
+             class IFoo(Interface):
                  taggedValue('key', 'value')
 
         .. seealso:: `zope.interface.taggedValue`
@@ -505,15 +505,15 @@ class IInterfaceDeclaration(Interface):
 
         For example::
 
-            def check_range(ob):
-                if ob.max < ob.min:
-                    range ValueError
+             def check_range(ob):
+                 if ob.max < ob.min:
+                     raise ValueError("max value is less than min value")
 
-            class IRange(Interface):
-                min = Attribute("The min value")
-                max = Attribute("The max value")
+             class IRange(Interface):
+                 min = Attribute("The min value")
+                 max = Attribute("The max value")
 
-                invariant(check_range)
+                 invariant(check_range)
 
         .. seealso:: `zope.interface.invariant`
         """
@@ -530,13 +530,13 @@ class IInterfaceDeclaration(Interface):
 
         For example::
 
-           class IRange(Interface):
-                @interfacemethod
-                def __adapt__(self, obj):
-                    if isinstance(obj, range):
-                       # Return the builtin ``range`` as-is
-                       return obj
-                    return super(type(IRange), self).__adapt__(obj)
+             class IRange(Interface):
+                 @interfacemethod
+                 def __adapt__(self, obj):
+                     if isinstance(obj, range):
+                         # Return the builtin ``range`` as-is
+                         return obj
+                     return super(type(IRange), self).__adapt__(obj)
 
         You can use ``super`` to call the parent class functionality. Note that
         the zero-argument version (``super().__adapt__``) works on Python 3.6 and above, but
diff --git a/src/zope/interface/tests/test_interface.py b/src/zope/interface/tests/test_interface.py
index 4bbed1a..036e858 100644
--- a/src/zope/interface/tests/test_interface.py
+++ b/src/zope/interface/tests/test_interface.py
@@ -2177,9 +2177,46 @@ class InterfaceTests(unittest.TestCase):
             pass
 
         self.assertEqual(42, I(object()))
-        # __adapt__ supercedes providedBy() if defined.
+        # __adapt__ can ignore the fact that the object provides
+        # the interface if it chooses.
         self.assertEqual(42, I(O()))
 
+    def test___call___w_overridden_adapt_and_conform(self):
+        # Conform is first, taking precedence over __adapt__,
+        # *if* it returns non-None
+        from zope.interface import Interface
+        from zope.interface import interfacemethod
+        from zope.interface import implementer
+
+        class IAdapt(Interface):
+            @interfacemethod
+            def __adapt__(self, obj):
+                return 42
+
+        class ISimple(Interface):
+            """Nothing special."""
+
+        @implementer(IAdapt)
+        class Conform24(object):
+            def __conform__(self, iface):
+                return 24
+
+        @implementer(IAdapt)
+        class ConformNone(object):
+            def __conform__(self, iface):
+                return None
+
+        self.assertEqual(42, IAdapt(object()))
+
+        self.assertEqual(24, ISimple(Conform24()))
+        self.assertEqual(24, IAdapt(Conform24()))
+
+        with self.assertRaises(TypeError):
+            ISimple(ConformNone())
+
+        self.assertEqual(42, IAdapt(ConformNone()))
+
+
     def test___call___w_overridden_adapt_call_super(self):
         import sys
         from zope.interface import Interface
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