Fix for QTBUG-18050: QXmlQuery crash

If QXmlQuery has a previous focus and an invalid xml is given
in setFocus, the old focus must be cleared. Otherwise the query
may be left in an inconsistent state.

Task-number: QTBUG-18050
Reviewed-by: Miikka Heikkinen

1 files changed, 5 insertions, 0 deletions

diff --git a/src/xmlpatterns/api/qxmlquery.cpp b/src/xmlpatterns/api/qxmlquery.cpp
index e69fe508d8..e5e901d315 100644
--- a/src/xmlpatterns/api/qxmlquery.cpp
+++ b/src/xmlpatterns/api/qxmlquery.cpp
@@ -988,7 +988,12 @@ bool setFocusHelper(QXmlQuery *const queryInstance,
     const QXmlItem focusItem(focusResult.next());
 
     if(focusItem.isNull() || focusResult.hasError())
+    {
+        /* The previous focus must be cleared in error situations.
+         * Otherwise the query may be left in an inconsistent state. */
+        queryInstance->setFocus(QXmlItem());
         return false;
+    }
     else
     {
         queryInstance->setFocus(focusItem);