bk commit into 5.1 tree (evgen:1.2671) BUG#32482

[eugene]

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ChangeSet@stripped, 2007-12-07 16:28:44+03:00, evgen@stripped +3 -0
  Bug#32482: Unchecked NULL caused server crash.
  
  The Item_func_set_user_var::register_field_in_read_map() wasn't checking 
  the result_filed to being null. This led to a server crash on queries which
  has ordering by such field and which don't employ temporary table.
  
  The Item_func_set_user_var::register_field_in_read_map() now checks the
  result_field to be not null.

  mysql-test/r/user_var.result@stripped, 2007-12-07 16:25:15+03:00, evgen@stripped +7 -0
    Added a test case for the bug#32482: Unchecked NULL caused server crash.

  mysql-test/t/user_var.test@stripped, 2007-12-07 16:24:57+03:00, evgen@stripped +8 -0
    Added a test case for the bug#32482: Unchecked NULL caused server crash.

  sql/item_func.cc@stripped, 2007-12-07 16:25:26+03:00, evgen@stripped +6 -3
    Bug#32482: Unchecked NULL caused server crash.
    The Item_func_set_user_var::register_field_in_read_map() now checks the
    result_field to be not null.

diff -Nrup a/mysql-test/r/user_var.result b/mysql-test/r/user_var.result
--- a/mysql-test/r/user_var.result	2007-06-04 09:07:19 +04:00
+++ b/mysql-test/r/user_var.result	2007-12-07 16:25:15 +03:00
@@ -353,3 +353,10 @@ select @a:=f4, count(f4) from t1 group b
 2.6	1
 1.6	4
 drop table t1;
+create table t1 (f1 int);
+insert into t1 values (1), (2);
+select @i := f1 as j from t1 order by 1;
+j
+1
+2
+drop table t1;
diff -Nrup a/mysql-test/t/user_var.test b/mysql-test/t/user_var.test
--- a/mysql-test/t/user_var.test	2007-06-03 16:06:53 +04:00
+++ b/mysql-test/t/user_var.test	2007-12-07 16:24:57 +03:00
@@ -237,3 +237,11 @@ select @a:=f2, count(f2) from t1 group b
 select @a:=f3, count(f3) from t1 group by 1 desc;
 select @a:=f4, count(f4) from t1 group by 1 desc;
 drop table t1;
+
+#
+# Bug#32482:  Unchecked NULL caused server crash.  
+#
+create table t1 (f1 int);
+insert into t1 values (1), (2);
+select @i := f1 as j from t1 order by 1;
+drop table t1;
diff -Nrup a/sql/item_func.cc b/sql/item_func.cc
--- a/sql/item_func.cc	2007-12-06 03:46:47 +03:00
+++ b/sql/item_func.cc	2007-12-07 16:25:26 +03:00
@@ -3848,9 +3848,12 @@ Item_func_set_user_var::fix_length_and_d
 
 bool Item_func_set_user_var::register_field_in_read_map(uchar *arg)
 {
-  TABLE *table= (TABLE *) arg;
-  if (result_field->table == table || !table)
-    bitmap_set_bit(result_field->table->read_set, result_field->field_index);
+  if (result_field)
+  {
+    TABLE *table= (TABLE *) arg;
+    if (result_field->table == table || !table)
+      bitmap_set_bit(result_field->table->read_set, result_field->field_index);
+  }
   return 0;
 }