--- a/hooks/syncsources.py	Wed Dec 01 17:09:19 2010 +0100
+++ b/hooks/syncsources.py	Wed Dec 01 17:11:35 2010 +0100
@@ -1,6 +1,7 @@
+from yams.schema import role_name
 from cubicweb import ValidationError
 from cubicweb.selectors import is_instance
-from cubicweb.server import hook
+from cubicweb.server import SOURCE_TYPES, hook
 
 class SourceHook(hook.Hook):
     __abstract__ = True
@@ -8,7 +9,7 @@
 
 
 class SourceAddedOp(hook.Operation):
-    def precommit_event(self):
+    def postcommit_event(self):
         self.session.repo.add_source(self.entity)
 
 class SourceAddedHook(SourceHook):
@@ -16,6 +17,10 @@
     __select__ = SourceHook.__select__ & is_instance('CWSource')
     events = ('after_add_entity',)
     def __call__(self):
+        if not self.entity.type in SOURCE_TYPES:
+            msg = self._cw._('unknown source type')
+            raise ValidationError(self.entity.eid,
+                                  {role_name('type', 'subject'): msg})
         SourceAddedOp(self._cw, entity=self.entity)
 
 
@@ -31,3 +36,13 @@
         if self.entity.name == 'system':
             raise ValidationError(self.entity.eid, {None: 'cant remove system source'})
         SourceRemovedOp(self._cw, uri=self.entity.name)
+
+class SourceRemovedHook(SourceHook):
+    __regid__ = 'cw.sources.removed'
+    __select__ = SourceHook.__select__ & hook.match_rtype('cw_support', 'cw_may_cross')
+    events = ('after_add_relation',)
+    def __call__(self):
+        entity = self._cw.entity_from_eid(self.eidto)
+        if entity.__regid__ == 'CWRType' and entity.name in  ('is', 'is_instance_of', 'cw_source'):
+            msg = self._cw._('the %s relation type can\'t be used here') % entity.name
+            raise ValidationError(self.eidto, {role_name(self.rtype, 'subject'): msg})