Patch zope.interface to remove docstrings and avoid publishing.

From Products.PloneHotfix20161129.

CHANGES.rst

@@ -11,6 +11,8 @@ https://zope.readthedocs.io/en/2.13/CHANGES.html
 Bugs Fixed
 ++++++++++
 
+- Patch zope.interface to remove docstrings and avoid publishing.
+  From Products.PloneHotfix20161129.
 
 Features Added
 ++++++++++++++

src/Zope2/App/patches/__init__.py

@@ -0,0 +1,2 @@
+# Import all patches.
+import publishing  # noqa

src/Zope2/App/patches/publishing.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+from zope.interface import Attribute
+from zope.interface import Interface
+from zope.interface.interface import Element
+from zope.interface.interface import Method
+
+
+def delete_method_docstring(klass, method_name):
+    # Delete the docstring from the class method.
+    # Objects must have a docstring to be published.
+    # So this avoids them getting published.
+    method = getattr(klass, method_name, None)
+    if (method is not None and hasattr(method, 'im_func') and
+            hasattr(method.im_func, '__doc__')):
+        del method.im_func.__doc__
+
+
+element_methods = [
+    'getDoc',
+    'getName',
+    'getTaggedValue',
+    'getTaggedValueTags',
+    'queryTaggedValue',
+    'setTaggedValue',
+]
+interface_methods = [
+    'changed',
+    'dependents',
+    'direct',
+    'extends',
+    'get',
+    'getBases',
+    'getDescriptionFor',
+    'implementedBy',
+    'interfaces',
+    'isEqualOrExtendedBy',
+    'isOrExtends',
+    'names',
+    'namesAndDescriptions',
+    'providedBy',
+    'queryDescriptionFor',
+    'subscribe',
+    'unsubscribe',
+    'validateInvariants',
+    'weakref',
+]
+
+for klass in [Element, Attribute, Interface, Method]:
+    try:
+        del klass.__doc__
+    except:
+        pass
+    for method_name in element_methods:
+        delete_method_docstring(klass, method_name)
+
+for method_name in interface_methods:
+    delete_method_docstring(Interface, method_name)

src/Zope2/App/startup.py

@@ -27,6 +27,7 @@
 from zope.processlifetime import DatabaseOpenedWithRoot
 
 from App.config import getConfiguration
+from Zope2.App import patches  # noqa
 import App.ZApplication
 import OFS.Application
 import Zope2