Bug#42495 updatexml: Assertion failed: xpath->context, file .\item_xmlfunc.cc, line 2507

Problem:
   RelativeLocationPath can appear only after a node-set expression
   in the third and the fourth branches of this rule:
     PathExpr :: =  LocationPath
                    | FilterExpr
                    | FilterExpr '/' RelativeLocationPath
                    | FilterExpr '//' RelativeLocationPath
   XPatch code didn't check the type of FilterExpr and crashed.
Fix:
   If FilterExpr is a scalar expression
   (variable reference, literal, number, scalar function call)
   return error.

1 files changed, 7 insertions, 1 deletions

diff --git a/sql/item_xmlfunc.cc b/sql/item_xmlfunc.cc
index 68d85418324..5601a2b18c6 100644
--- a/sql/item_xmlfunc.cc
+++ b/sql/item_xmlfunc.cc
@@ -1969,6 +1969,13 @@ my_xpath_parse_FilterExpr_opt_slashes_RelativeLocationPath(MY_XPATH *xpath)
   if (!my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH))
     return 1;
 
+  if (xpath->item->type() != Item::XPATH_NODESET)
+  {
+    xpath->lasttok= xpath->prevtok;
+    xpath->error= 1;
+    return 0;
+  }
+
   my_xpath_parse_term(xpath, MY_XPATH_LEX_SLASH);
   return my_xpath_parse_RelativeLocationPath(xpath);
 }
@@ -1976,7 +1983,6 @@ static int my_xpath_parse_PathExpr(MY_XPATH *xpath)
 {
   return my_xpath_parse_LocationPath(xpath) || 
          my_xpath_parse_FilterExpr_opt_slashes_RelativeLocationPath(xpath);
-         
 }