Bug#16318: XML: extractvalue() incorrectly returns last() = 1

xml.result, xml.test:
  Adding test case.
item_xmlfunc.cc:
  - adding "size" member into MY_XPATH_FLT struct,
  to pass parent's context size when iterating
  in a predicate. Previously, temporaty context
  size was calculated instead, which is always 1.
  As a result, things like last() and count() 
  didn't work fine.
  - adding iteration into Item_func_xpath_elementbyindex:
  similar to Item_func_xpath_predicate.
  This is to make things like last() and count()
  work inside square brackets.


sql/item_xmlfunc.cc:
  Bug#16318: XML: extractvalue() incorrectly returns last() = 1
  - adding "size" member into MY_XPATH_FLT struct,
  to pass parent's context size when iterating
  in a predicate. Previously, temporaty context
  size was calculated instead, which is always 1.
  As a result, things like last() and count() 
  didn't work fine.
  - adding iteration into Item_func_xpath_elementbyindex:
  similar to Item_func_xpath_predicate.
  This is to make things like last() and count()
  work inside square brackets.
mysql-test/t/xml.test:
  Adding test case.
mysql-test/r/xml.result:
  Adding test case.

1 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/t/xml.test b/mysql-test/t/xml.test
index 6a91d785d4e..b4272c7cabc 100644
--- a/mysql-test/t/xml.test
+++ b/mysql-test/t/xml.test
@@ -254,3 +254,19 @@ 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#16318: XML: extractvalue() incorrectly returns last() = 1
+#
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[position()]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=last()]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()-1]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=1]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=2]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=position()]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)-1]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=1]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=2]');
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=position()]');