Bug#16316: XML: extractvalue() is case-sensitive with contains()

xml.result, xml.test:
  Adding test case.
item_xmlfunc.cc:
  Fixed that Item_nodeset_func derived classes
  didn't take into account charset of the XML value
  and always worked using "binary" charset.

mysql-test/r/xml.result

@@ -561,3 +561,15 @@ A B C
 select extractvalue('<A_B>A</A_B>','/A_B');
 extractvalue('<A_B>A</A_B>','/A_B')
 A
+select extractvalue('<a>Jack</a>','/a[contains(../a,"J")]');
+extractvalue('<a>Jack</a>','/a[contains(../a,"J")]')
+Jack
+select extractvalue('<a>Jack</a>','/a[contains(../a,"j")]');
+extractvalue('<a>Jack</a>','/a[contains(../a,"j")]')
+Jack
+select extractvalue('<a>Jack</a>','/a[contains(../a,"j")]' collate latin1_bin);
+extractvalue('<a>Jack</a>','/a[contains(../a,"j")]' collate latin1_bin)
+
+select extractvalue('<a>Jack</a>' collate latin1_bin,'/a[contains(../a,"j")]');
+extractvalue('<a>Jack</a>' collate latin1_bin,'/a[contains(../a,"j")]')
+

mysql-test/t/xml.test

@@ -254,3 +254,11 @@ select extractvalue('<a>A<b>B<c>C</c></b></a>','/a/descendant-or-self::*');
 # Bug #16320 XML: extractvalue() won't accept names containing underscores
 #
 select extractvalue('<A_B>A</A_B>','/A_B');
+
+#
+# Bug#16316: XML: extractvalue() is case-sensitive with contains()
+#
+select extractvalue('<a>Jack</a>','/a[contains(../a,"J")]');
+select extractvalue('<a>Jack</a>','/a[contains(../a,"j")]');
+select extractvalue('<a>Jack</a>','/a[contains(../a,"j")]' collate latin1_bin);
+select extractvalue('<a>Jack</a>' collate latin1_bin,'/a[contains(../a,"j")]');

sql/item_xmlfunc.cc

@@ -206,7 +206,11 @@ public:
     return str;
   }
   enum Item_result result_type () const { return STRING_RESULT; }
-  void fix_length_and_dec() { max_length=  MAX_BLOB_WIDTH; }
+  void fix_length_and_dec()
+  {
+    max_length= MAX_BLOB_WIDTH;
+    collation.collation= pxml->charset();
+  }
   const char *func_name() const { return "nodeset"; }
 };
 
@@ -2373,6 +2377,7 @@ void Item_xml_str_func::fix_length_and_dec()
   xpath.cs= collation.collation;
   xpath.debug= 0;
   xpath.pxml= &pxml;
+  pxml.set_charset(collation.collation);
 
   rc= my_xpath_parse(&xpath, xp->ptr(), xp->ptr() + xp->length());