fail gracefully when a schema lookup fails do to import error in lookupSchema

docs/HISTORY.txt

@@ -1,14 +1,24 @@
 Changelog
 =========
 
-2.1.2 (unreleased)
+2.1.3 (unreleased)
+------------------
+- Fail gracefully when a schema lookup fails due to schema that doesn't 
+  exist or no longer exists for some reason or another. 
+  [eleddy]
+
+- Add convenience functions (aka sanity) for getting
+  dexterity fields and behavior fields in a consistent way
+  [eleddy]
+
+
+2.1.2 (2013-03-05)
 ------------------
 
 - Merged Rafael Oliveira's (@rafaelbco) @content-core views from
   collective.cmfeditionsdexteritycompat.
   [rpatterson]
 
-
 2.1.1 (2013-01-17)
 ------------------
 

plone/dexterity/fti.py

@@ -1,4 +1,5 @@
 import os.path
+import logging
 
 from zope.interface import implements
 
@@ -204,12 +205,18 @@ class DexterityFTI(base.DynamicViewTypeInformation):
         return not(self.schema)
     
     def lookupSchema(self):
+        schema = None
         
         # If a specific schema is given, use it
         if self.schema:
-            schema = utils.resolveDottedName(self.schema)
-            if schema is None:
-                raise ValueError(u"Schema %s set for type %s cannot be resolved" % (self.schema, self.getId()))
+            try:
+                schema = utils.resolveDottedName(self.schema)
+            except ImportError:
+                logging.warning(u"Schema %s set for type %s cannot be resolved" % (self.schema, self.getId()))
+                # fall through to return a fake class with no
+                # fields so that end user code doesn't break
+                
+        if schema:
             return schema
         
         # Otherwise, look up a dynamic schema. This will query the model for

plone/dexterity/tests/test_fti.py

@@ -87,6 +87,20 @@ class TestFTI(MockTestCase):
         # cleanup
         delattr(plone.dexterity.schema.generated, schemaName)
 
+    def test_lookupSchema_with_nonexistant_schema(self):
+        """ Tests the case where a dexterity type is not removed cleanly
+        from the fti, but the code has been removed.
+        """
+        fti = DexterityFTI(u"testtype")
+        fti.schema = 'model.wont.be.imported'
+        portal = self.create_dummy(getPhysicalPath=lambda:('', 'site'))
+        self.mock_utility(portal, ISiteRoot)
+        schemaName = utils.portalTypeToSchemaName(fti.getId())
+        setattr(plone.dexterity.schema.generated, schemaName, ITestSchema)
+        self.assertEquals(ITestSchema, fti.lookupSchema())
+        delattr(plone.dexterity.schema.generated, schemaName)
+
+
     def test_lookupModel_from_string(self):
         fti = DexterityFTI(u"testtype")
         fti.schema = None