Make CloneAction abstract

we don't want it to appear auto-magically for every IClonable entities

test/data/entities.py

-from cubicweb.predicates import has_related_entities
+from cubicweb.predicates import has_related_entities, is_instance
 
 from cubes.compound.entities import (IClonableAdapter, IContained, IContainer,
                                      structure_def)
@@ -2,6 +2,7 @@
 
 from cubes.compound.entities import (IClonableAdapter, IContained, IContainer,
                                      structure_def)
+from cubes.compound.views import CloneAction
 
 
 def agent_structure_def(schema):
@@ -22,6 +23,10 @@
     follow_relations = [('member', 'object')]
 
 
+class AgentCloneAction(CloneAction):
+    __select__ = CloneAction.__select__ & is_instance('Agent')
+
+
 def registration_callback(vreg):
     vreg.register_all(globals().values(), __name__)
     vreg.register(IContainer.build_class('Agent'))

views.py

@@ -26,9 +26,16 @@
 
 
 class CloneAction(actions.CopyAction):
-    """Just a copy action (copy is handled by edit controller below) named 'clone'."""
-    __select__ = (actions.CopyAction.__select__ & one_line_rset() &
-                  adaptable('IClonable') & has_permission('add'))
+    """Abstract clone action of ICloneable entities.
+
+    Simply inherit from it with a specific selector if you want to activate it.
+    The action will link to the copy form with shallow copy message disabled and
+    linkto information to rely on the clone hook for the actual cloning.
+    """
+    __abstract__ = True
+    __select__ = (actions.CopyAction.__select__ & one_line_rset()
+                  & has_permission('add')
+                  & adaptable('IClonable'))
     title = _('clone')
 
     def url(self):
@@ -38,6 +45,8 @@
         return entity.absolute_url(vid='copy', __linkto=linkto)
 
 
+# In any case IClonable entities want default copy disabled since it wont handle
+# composite relations by default.
 actions.CopyAction.__select__ &= ~adaptable('IClonable')