[FIX] nuke ir.model.data caches before starting imports

Otherwise a previous validation (or 2) will poison the cache and the
import itself will fail even though the validation succeeeded (and
importing with no validation would have succeeded), as the orm cache
doesn't take DB rollbacks in account.

bzr revid: xmo@openerp.com-20121109113951-p3qgg6m5g7poay5e

openerp/addons/base/ir/ir_model.py

@@ -878,11 +878,18 @@ class ir_model_data(osv.osv):
             id = False
         return id
 
+    def clear_caches(self):
+        """ Clears all orm caches on the object's methods
+
+        :returns: itself
+        """
+        self._get_id.clear_cache(self)
+        self.get_object_reference.clear_cache(self)
+        return self
 
     def unlink(self, cr, uid, ids, context=None):
         """ Regular unlink method, but make sure to clear the caches. """
-        self._get_id.clear_cache(self)
-        self.get_object_reference.clear_cache(self)
+        self.clear_caches()
         return super(ir_model_data,self).unlink(cr, uid, ids, context=context)
 
     def _update(self,cr, uid, model, module, values, xml_id=False, store=True, noupdate=False, mode='init', res_id=False, context=None):

openerp/osv/orm.py

@@ -1325,7 +1325,8 @@ class BaseModel(object):
         messages = []
 
         fields = map(fix_import_export_id_paths, fields)
-        ModelData = self.pool['ir.model.data']
+        ModelData = self.pool['ir.model.data'].clear_caches()
+
         fg = self.fields_get(cr, uid, context=context)
 
         mode = 'init'