From 961cc887bfae0551682ca3f2db7d92147aafd7e4 Mon Sep 17 00:00:00 2001
From: unknown <ramil/ram@mysql.com/ramil.myoffice.izhnet.ru>
Date: Wed, 21 Nov 2007 16:00:09 +0400
Subject: Fix for bug #32557: order by updatexml causes assertion in filesort

Problem: even if an Item_xml_str_func successor returns NULL, it doesn't have
a corresponding property (maybe_null) set, that leads to a failed assertion.

Fix: set nullability property of Item_xml_str_func.


mysql-test/r/xml.result:
  Fix for bug #32557: order by updatexml causes assertion in filesort
    - test result.
mysql-test/t/xml.test:
  Fix for bug #32557: order by updatexml causes assertion in filesort
    - test case.
sql/item_xmlfunc.h:
  Fix for bug #32557: order by updatexml causes assertion in filesort
    - set Item_xml_str_func::maybe_null.
---
 mysql-test/r/xml.result |  7 +++++++
 mysql-test/t/xml.test   |  8 ++++++++
 sql/item_xmlfunc.h      | 12 ++++++++++--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/xml.result b/mysql-test/r/xml.result
index d98173dbe15..56c884343e3 100644
--- a/mysql-test/r/xml.result
+++ b/mysql-test/r/xml.result
@@ -1022,4 +1022,11 @@ NULL	NULL	NULL
 select updatexml(NULL, NULL, NULL);
 updatexml(NULL, NULL, NULL)
 NULL
+CREATE TABLE t1(a INT NOT NULL);
+INSERT INTO t1 VALUES (0), (0);
+SELECT 1 FROM t1 ORDER BY(UPDATEXML(a, '1', '1'));
+1
+1
+1
+DROP TABLE t1;
 End of 5.1 tests
diff --git a/mysql-test/t/xml.test b/mysql-test/t/xml.test
index 6c7d9af1b63..5ca9c7afd76 100644
--- a/mysql-test/t/xml.test
+++ b/mysql-test/t/xml.test
@@ -543,4 +543,12 @@ select updatexml(NULL, NULL, 1), updatexml(1, NULL, NULL),
        updatexml(NULL, 1, NULL);
 select updatexml(NULL, NULL, NULL);
 
+#
+# Bug #32557: order by updatexml causes assertion in filesort
+#
+CREATE TABLE t1(a INT NOT NULL);
+INSERT INTO t1 VALUES (0), (0);
+SELECT 1 FROM t1 ORDER BY(UPDATEXML(a, '1', '1'));
+DROP TABLE t1;
+
 --echo End of 5.1 tests
diff --git a/sql/item_xmlfunc.h b/sql/item_xmlfunc.h
index 278c98baf7c..dadbb5ccf42 100644
--- a/sql/item_xmlfunc.h
+++ b/sql/item_xmlfunc.h
@@ -28,8 +28,16 @@ protected:
   String tmp_value, pxml;
   Item *nodeset_func;
 public:
-  Item_xml_str_func(Item *a, Item *b): Item_str_func(a,b) {}
-  Item_xml_str_func(Item *a, Item *b, Item *c): Item_str_func(a,b,c) {}
+  Item_xml_str_func(Item *a, Item *b): 
+    Item_str_func(a,b) 
+  {
+    maybe_null= TRUE;
+  }
+  Item_xml_str_func(Item *a, Item *b, Item *c): 
+    Item_str_func(a,b,c) 
+  {
+    maybe_null= TRUE;
+  }
   void fix_length_and_dec();
   String *parse_xml(String *raw_xml, String *parsed_xml_buf);
 };
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