register adapter only for plone.app.layout>=2.8.0

CHANGES.rst

@@ -4,7 +4,8 @@ Changelog
 2.1.1 (unreleased)
 ------------------
 
-- Fluid row styles only make sense on pages without portlets and are now only active if no portlet columns are shown.
+- Fluid row styles only make sense on pages without portlets.
+  In Plone 5.1.3 we can check that automatically (with plone.app.layout 2.8.0) and those styles are only active if no portlet columns are shown.
   [agitator]
 
 

README.rst

@@ -78,6 +78,7 @@ Subcolumns
 
 Fluid rows
     For fluid (full width) rows select any tile in the row and choose "Fluid" from the "Format" menu.
+    Fluid row styles only make sense on pages without portlets. In Plone 5.1.3 we can check that automatically (with plone.app.layout 2.8.0) and those styles are only active if no portlet columns are shown.
 
 
 Installation

src/plone/app/mosaic/layoutpolicy.py

@@ -1,10 +1,16 @@
 # -*- coding: utf-8 -*-
-from plone.app.layout.globals.interfaces import IBodyClassAdapter
 from plone.portlets.interfaces import IPortletManager
 from plone.portlets.interfaces import IPortletRetriever
 from zope.component import getMultiAdapter
 from zope.component import getUtility
 from zope.interface import implementer
+from zope.interface import Interface
+
+try:
+    from plone.app.layout.globals.interfaces import IBodyClassAdapter
+except Exception as e:
+    class IBodyClassAdapter(Interface):
+        """ Pseudo adapter class if plone.app.layout is < 2.8.0 """
 
 
 @implementer(IBodyClassAdapter)