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, 36 insertions, 0 deletions

diff --git a/mysql-test/r/xml.result b/mysql-test/r/xml.result
index 0b75b50f754..da2e2e400ad 100644
--- a/mysql-test/r/xml.result
+++ b/mysql-test/r/xml.result
@@ -561,3 +561,39 @@ A B C
 select extractvalue('<A_B>A</A_B>','/A_B');
 extractvalue('<A_B>A</A_B>','/A_B')
 A
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[position()]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[position()]')
+B1 B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=last()]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=last()]')
+B1 B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()]')
+B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()-1]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()-1]')
+B1
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=1]');
+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]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=2]')
+B1 B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=position()]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[last()=position()]')
+B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)]')
+B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)-1]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)-1]')
+B1
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=1]');
+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]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=2]')
+B1 B2
+select extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=position()]');
+extractvalue('<a>A<b>B1</b><b>B2</b></a>','/a/b[count(.)=position()]')
+B2