Bug#16315 XML: extractvalue() handles self badly

xml.result, xml.test:
  Adding test case.
item_xmlfunc.cc:
  Adding a special function to handle "self" axis.
  Previously "child" and "self" were handled the same.

mysql-test/r/xml.result

@@ -65,6 +65,9 @@ c1
 SELECT extractValue(@xml,'/a/child::*');
 extractValue(@xml,'/a/child::*')
 b1 b2
+SELECT extractValue(@xml,'/a/self::*');
+extractValue(@xml,'/a/self::*')
+a1 a2
 SELECT extractValue(@xml,'/a/descendant::*');
 extractValue(@xml,'/a/descendant::*')
 b1 c1 b2
@@ -546,3 +549,12 @@ select extractvalue('<a>A</a>','/<a>');
 ERROR HY000: XPATH syntax error: '>'
 select extractvalue('<a><b>b</b><b!>b!</b!></a>','//b!');
 ERROR HY000: XPATH syntax error: '!'
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant::*');
+extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant::*')
+B C
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/self::*');
+extractvalue('<a>A<b>B<c>C</c></b></a>','/a/self::*')
+A
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant-or-self::*');
+extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant-or-self::*')
+A B C

mysql-test/t/xml.test

@@ -23,6 +23,7 @@ SELECT extractValue(@xml,'/*/*');
 SELECT extractValue(@xml,'/*/*/*');
 
 SELECT extractValue(@xml,'/a/child::*');
+SELECT extractValue(@xml,'/a/self::*');
 SELECT extractValue(@xml,'/a/descendant::*');
 SELECT extractValue(@xml,'/a/descendant-or-self::*');
 SELECT extractValue(@xml,'/a/attribute::*');
@@ -243,3 +244,10 @@ select extractvalue('<a>A</a>','/<a>');
 #
 --error 1105
 select extractvalue('<a><b>b</b><b!>b!</b!></a>','//b!');
+
+#
+# Bug #16315 XML: extractvalue() handles self badly
+#
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant::*');
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/self::*');
+select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant-or-self::*');

sql/item_xmlfunc.cc

@@ -252,6 +252,18 @@ class Item_nodeset_func_axisbyname :public Item_nodeset_func
 };
 
 
+/* Returns self */
+class Item_nodeset_func_selfbyname: public Item_nodeset_func_axisbyname
+{
+public:
+  Item_nodeset_func_selfbyname(Item *a, const char *n_arg, uint l_arg,
+                                String *pxml): 
+    Item_nodeset_func_axisbyname(a, n_arg, l_arg, pxml) {}
+  const char *func_name() const { return "xpath_selfbyname"; }
+  String *val_nodeset(String *nodeset);
+};
+
+
 /* Returns children */
 class Item_nodeset_func_childbyname: public Item_nodeset_func_axisbyname
 {
@@ -572,6 +584,20 @@ String * Item_nodeset_func_union::val_nodeset(String *nodeset)
 }
 
 
+String *Item_nodeset_func_selfbyname::val_nodeset(String *nodeset)
+{
+  prepare(nodeset);
+  for (MY_XPATH_FLT *flt= fltbeg; flt < fltend; flt++)
+  {
+    uint pos= 0;
+    MY_XML_NODE *self= &nodebeg[flt->num];
+    if (validname(self))
+      ((XPathFilter*)nodeset)->append_element(flt->num,pos++);
+  }
+  return nodeset;
+}
+
+
 String *Item_nodeset_func_childbyname::val_nodeset(String *nodeset)
 {
   prepare(nodeset);
@@ -945,6 +971,9 @@ static Item* nametestfunc(MY_XPATH *xpath,
   case MY_XPATH_AXIS_ATTRIBUTE:
     res= new Item_nodeset_func_attributebyname(arg, beg, len, xpath->pxml);
     break;
+  case MY_XPATH_AXIS_SELF:
+    res= new Item_nodeset_func_selfbyname(arg, beg, len, xpath->pxml);
+    break;
   default:
     res= new Item_nodeset_func_childbyname(arg, beg, len, xpath->pxml);
   }