When adding a date attribute to a content class, existing object attributes of this class have data_int set to NULL. eZ Find fails to index such objects. Solr receives this as an empty string, which is not a valid date value.

If the affected objects are republished, data_int changes to 0 (zero) and indexing works.

In addition to the fix, a script is needed for fixing existing objects affected by this problem, unless the fix can work around the problem.

Steps to reproduce

• Add a date attribute to a class
• Reindex using extension/ezfind/bin/php/updatesearchindexsolr.php
• Note that objects of the given class fails to be indexed.
• The indexer reports: "Failed indexing object with ID [42]"
• Solr reports: "SEVERE: org.apache.solr.common.SolrException: Invalid Date String:''
  at org.apache.solr.schema.DateField.parseMath(DateField.java:165)"