erp5_catalog: Check if object already exists before making a copy in ERP5Catalog

product/ERP5/ERP5Site.py

@@ -1728,9 +1728,9 @@ class ERP5Site(FolderMixIn, CMFSite, CacheCookieMixin):
       # Copy-paste objects from SQLCatalog to ERP5Catalog
       for id in sql_catalog.objectIds():
         ob = sql_catalog._getOb(id)
-        # Check if the object is copyable
+        # Check if the object is copyable and that it doesn't already exist
         # The copying attributes are from OFS.CopySupport
-        if hasattr(ob, '_canCopy'):
+        if hasattr(ob, '_canCopy') and not new_erp5_catalog.has_key(id):
           # Get a copy of object for new conainer, i.e. new_erp5_catalog
           ob = ob._getCopy(new_erp5_catalog)
           ob._setId(id)