Wikimedia Bugzilla is closed!

Created attachment 14728 [details]
Fixed SMW_SparqlStoreQueryEngine.php file

OS: Centos 6.5
MediaWiki: 1.22.2

When I try to execute a sparql query with an order-by clause I have the following error:
Unexpected non-MediaWiki exception encountered, of type "SMWSparqlDatabaseError"  . The output of sparql validator query is: "Unresolved prefixed name".

==============================================================================
Output query example:

PREFIX wiki: <http://.....>
PREFIX rdf: <http://.....>
PREFIX rdfs: <http://.....>
PREFIX owl: <http://.....>
PREFIX swivt: <http://.....>
PREFIX property: <http:.....>
PREFIX xsd: <http://.....>
PREFIX yyy: <http://.....>
SELECT DISTINCT ?result WHERE {
?result xxx:some_instance ?v2 .
{ ?result rdf:type wiki:Categoria_instance . }
?result yyy:isVersionOf ?someVersion .

}
ORDER BY ASC(?v2) 
OFFSET 0
LIMIT 501

The xxx prefix is not present in prefix list
==============================================================================

A possible solution we found to fix this problem is to modify addMissingOrderByConditions method in the class extensions/SemanticMediaWiki/includes/storage/SMW_SparqlStoreQueryEngine.php, adding the following line  
$sparqlCondition->namespaces = array_merge($sparqlCondition->namespaces, $auxSparqlCondition->namespaces); 

after line 942:

$sparqlCondition->weakConditions[$sparqlCondition->orderVariables[$propkey]] = $auxSparqlCondition->getWeakConditionString() . $auxSparqlCondition->getCondition();

I have attached to this issue the fixed class file.